Equipment for the treatment of loads or residues of non-ferrous metals and their alloys include a rotary furnace having a vessel with a sealed door. An electrode is introduced into the rotary furnace and is used to establish a free burning convective electric arc with the load introduced into the furnace or with the furnaces bottom wall. The equipment is assembled over a hinged base which allows elevating or lowering its rotation axis with respect to a horizontal plane.

Rotary furnaces are widely used in non-ferrous metal recycling industries for the melting and recovery of pure metal or alloys, as contained in scraps such as empty beverage cans, unusable utensils, laminated profiles, casts, industry chips, waste from production such as cuttings, and also to recover metal contained in drosses generated by industrial processes involving the melting of said metals.
Typically, rotary furnaces operated to recycle non-ferrous metals have a chamber-like metal shell with rotational symmetry to a lengthwise axis, which is internally lined with one or more layers of appropriate refractory material for operation at temperatures above the melting point of the metal. Said chamber is submitted to rotational movement around its lengthwise axis (rotation axis) for tumbling and revolving the material to be processed loaded within it. The furnace rotation axis may or not be inclined with respect to the horizontal plane. No matter which is the way of supplying the energy required to heat and melt the material, the process is carried out in batches, following a processing cycle basically comprising the following steps:
1. Loading the scrap or dross to be processed into the furnace. In case of furnaces heated with oil or gas burners, a protective salt composition is loaded and melted before this step to form a bath in which the material to be processed will be immersed when scraps are treated, or the salt composition will be simultaneously mixed and heated with dross in case of dross treatment.
2. Heating the load and melting the metal to be recovered. During this operating step the furnace is rotationally moved, fully rotating or just oscillating, to revolve the load within it and therefore promoting a better heat transfer between the energy source, the furnace wall and the load.
3. Revolving the load, which may involve or not the addition of extra energy, by rotationally moving the furnace, fully rotating or just oscillating, to promote the coalescence of dispersed fractions of the molten metal, followed by precipitation to a liquid metal bath that forms under a non-metallic solid residue layer along the process.
4. When the separation stage between metal and the non-metal solid fraction is concluded, the molten metal is tapped to outside the furnace, usually into ingot molds.
5. Emptying the furnace cavity by removing the non-metallic solid residue.
Recycling of non-ferrous metals, mainly aluminum, by using furnaces heated by oil or gas burners has the main disadvantage of requiring the addition of melting salts to the load, so to inhibit the oxidation of recoverable free metal and thus to improve the metal yield of the process. The amount of salts used in this case is, in practice, of the same order of magnitude in mass as the quantity of oxides originally contained in the load. Generally, equimolar mixtures of NaCl and KCl are used (eutectic composition). This composition presents a melting point of 667° C., which is compatible with aluminum processing temperatures, and may have fluoride salts added with the purpose of improving salt wettability. Once melted, these salts promote a metal coverage layer that minimizes metal oxidation.
The need of having salts added to improve the metal recovery yield is a disadvantage for processes using oil or gas burners. Heating and melting of salts produce fumes which, besides being pollutant and harmful agents to human health, are also highly corrosive, causing deterioration of the furnace and other industrial equipment and installations used in the process. Another disadvantage of said processes results from the presence of these salts in the non-metal residue as generated after the metal is recovered, also known as salt cake. Without industrial application, these residues are sent to industrial landfills. Besides being expensive, this practice presents environmental risks, since the salts contained in such residues may be easily leached and thus contaminate soils, ground water, rivers and lakes.
The patents CA 1255914 and U.S. Pat. No. 4,959,100, in name of Alcan International Limited, Canada, present a method and device to treat non-ferrous metal dross, particularly aluminum, by making use of a rotary furnace heated by a high temperature gas flame. Said patents claim a process which does not use molten salts and employs a plasma torch with two electrodes, of contained-arc type (plasma gas heaters). Such plasma torch is supplied with a gas stream which, once heated, is introduced into the furnace to promote the melting of the metal contained in the load fed into it. The patent EP 0400925, also in name of Alcan International Limited, Canada, presents a process essentially using the same device as disclosed by the patents CA 1255914 and U.S. Pat. No. 4,959,100, but adapted to melt scraps contaminated with organic material. This process is characterized by removing said contaminants by previously heating the load with the plasma torch, at a temperature below the melting point of the metal, to volatilize the organic material before the load is heated to a higher temperature in order to promote the melting of the metal.
As explained by the patents CA 1255914 and U.S. Pat. No. 4,959,100, plasma torches which may be used to embody the invention as claimed are like the ones manufactured by the company Plasma Energy Corporation, USA. In an article by Alcan International Limited, written by S. Lavoie and J. Lachance, on the recovery of aluminum from primary dross (Five years of industrial experience with the plasma dross treatment process, presented in the Third International Symposium of Recycling of Metals and Engineered Materials, Alabama, USA, Nov. 12-15, 1995), the use of plasma torches manufactured by Westinghouse, USA, type Mark UR, is also mentioned. Whatever the manufacturer, said type of plasma torch is described as a device which presents the following characteristics: it is used to heat large amounts of gas as introduced there within and, by its use, supplied to the process to heat the furnace walls and the load itself; for the sake of achieving an efficient heat transfer between gas and load, plasma torch of said construction is a device that depends on the use of diatomic gases, like air and pure nitrogen; it requires stabilizing mechanisms to sustain the arc within it; it depends on means to obtain working life times of electrode which are compatible with the processes to which it is intended to; which is usually reached by feeding the gas as a vortex and/or by using external means to the torch itself, such as external magnetic fields; and requires intense cooling of electrodes which, besides presenting risk of explosion in case water leakage occurs into the furnace, also results in loss of efficiency of the electric energy conversion into thermal energy as contained in the heated gases.
Although the use of plasma as a heating source allows the choice of a wide range of the composition of gases to be used in the process, in case of plasma generation by using plasma torches with two contained electrodes which, as described above, are essentially intended to heat large volumes of gas, for economical reasons in industrial applications involving metal recovery using rotary furnaces, atmospheric air (compressed air) or pure nitrogen are used, as shown by the examples included in the patents CA 1255914 and U.S. Pat. No. 4,959,100. Another reason to choose air or nitrogen in this process, in comparison with the use of inert gases, is that, being diatomic gases, they have considerably higher heat capacity. This is an important characteristic, in this case, in order to promote an efficient energy transfer between the gas which is heated while passing through the plasma torch and the load into the furnace.
The use of air as plasma gas, and consequently as the gas forming the furnace atmosphere, results in the main technical limitation of the process object of the patents CA 1255914 and U.S. Pat. No. 4,959,100, especially in the case of aluminum. Aluminum reacts with oxygen and, more moderately, also with the nitrogen present in air, respectively forming aluminum oxide and aluminum nitride. Both reactions are exothermic, being that the reaction between aluminum and oxygen releases the greatest amount of energy, the two reactions compared. Although the energy released by aluminum oxidation contributes to heat the load, as recognized by Lavoie and Lachance in the above referred article, the added economical value to aluminum as recovered metal does not justify the substitution of electric energy by the energy resulting from metal burning or oxidation. In the mentioned article, Lavoie and Lachance inform that, when the furnace is operated with compressed air, free aluminum oxidation generates about 125 kWh per ton of processed dross. Said quantity of energy, as informed in the article, represents 40 to 50% of the total energy required by the process. A similar situation occurs in an example supplied by the patent U.S. Pat. No. 4877448, owned by the company Plasma Energy Corporation, USA. In that example, the use of a plasma torch fed with compressed air results in the oxidation of 4.6% of the recoverable aluminum, generating an additional energy of about 40% of the electric energy as supplied by air heating with the plasma torch. Although the heating method as suggested by the mentioned patents avoids the use of molten salts, one of its disadvantages results from the fact that, for economic industrial use, it depends on the use low cost gases that have high heat capacity, but which unavoidably react with part of the free recoverable aluminum, thus reducing the process metal yield. The use of different gases in different stages of a melting cycle, as also suggested by the patents CA 1255914 and U.S. Pat. No. 4,959,100, makes the furnace operation with this form of heating far more complex. An environmental disadvantage also results from the use of a plasma torch fed with nitrogen, combined with oxygen as present in air or as a pure gas, also recognized by the patents CA 1255914 and U.S. Pat. No. 4,959,100. As previously mentioned, nitrogen reacts with liquid aluminum to form aluminum nitride. Besides causing the loss of recoverable metal, aluminum nitride remains in the solid residues of the process and, while handling or discarding said residue, slowly reacts with water (from air moisture or weathering) to produce ammonia, which is environmentally undesirable.
Patents CA 1255914 and U.S. Pat. No. 4,959,100 also suggest the use of plasma torches of transferred-arc type in their respective processes. However, they do not explain how said arc transference can be made in practice, the technical conditions for said embodiment, nor do they inform the advantages resulting from their use.
Patents CA 2030727 and U.S. Pat. No. 5,245,627, in name of Hydro-Quebec, Canada, claim processes to treat dross containing a metal, bearing in mind its recovery, based on heating the material inside a rotating furnace by a radiating transferred-arc plasma as established between two opposed electrodes, one at each end of the cavity and aligned to the furnace horizontal rotation axis, specifically mentioning the recovery of the metal as contained in primary aluminum dross.
As explained by the patents CA 2030727 and U.S. Pat. No. 5,245,627, both electrodes, preferably manufactured with graphite, may be displaced over the rotation axis of the furnace, both to adjust the length of the electric arc and to compensate for electrode erosion suffered during arc operation. With the purpose of stabilizing the arc at the center of the cavity and along the rotation axis of the furnace, it is suggested the feeding of a gas, still at a low flow rate, through at least one of said electrodes. As also explained in such patents, the main feature of the geometry and way of generating the electric arc between two opposed electrodes is that they promote heating of the furnace walls and the load essentially by means of the radiation issued from the arc, once the furnace is moved around the arc, with a minimum of gas flow, being such a gas fully inert or not to aluminum, but which is introduced into the furnace with the main purpose of stabilizing the radiating arc. Moreover, as explained by the patents CA 2030727 and U.S. Pat. No. 5,245,627, the process is characterized by the radiating arc furnace used to have a rotation axis with which both electrodes are aligned and which remains horizontal when the furnace is in operation.
The use of a radiating electric arc, transferred between two electrodes aligned with the lengthwise or rotation axis of the furnace, positioned over the processed material, as disclosed in the patents CA 2030727 and U.S. Pat. No. 5,245,627, allows to eliminate the disadvantages related to the industrial use under economic conditions of a plasma torch fed with inert gas, as suggested by the patents CA 1255914 and U.S. Pat. No. 4,959,100. In fact, the use of a radiating electric arc allows to use substantially lower flow rates of inert gas, whose purpose is to stabilize the arc within the furnace axis. However, this method has the following disadvantages: risk of breaking the electrodes which, once located along the horizontal rotation axis of the furnace, are prone to shocks with large chunks of material typically found in aluminum dross; the use of two electrodes as suggested does not allow inclination of the furnace lengthwise axis during operation, which would allow to increase the amount of material which can be fed for a given volume of cavity, but which would increase the risk of contact between one of the electrodes with the processed material, and thus would more easily cause electrodes to be broken.
The creation of means to avoid the formation of hot spots in the material being treated is a common condition observed in the processes making use of both a plasma torch and a radiating electric arc. This fact is particularly mentioned by the patents as filed by Alcan International Limited, CA 1255914 and U.S. Pat. No. 4,959,100. Therefore, the following operational procedure in each of the previously revised processes can be observed: in the equipment that makes use of a two electrodes, contained arc type plasma torch, the high temperature flame must be directed to the side walls of the furnace, away from the load; in the equipment that makes use of a radiating electric arc, this arc is established between two electrodes aligned with the lengthwise rotational axis of the furnace which, once horizontally positioned while in operation, is therefore kept away from the load being treated to avoid its contact with the electrodes and the arc itself.
The present invention has the objective of providing a new process and equipment to recover non-ferrous metals, present in the corresponding scraps, as well as in drosses generated by the industrial processes involving the melting of the metal, involving their melting, particularly of aluminum and its alloys, which allows to eliminate the above mentioned disadvantages.
The following are particular advantages of the present invention: to provide a process which does not make use of melting salts; which is thermally more efficient than the currently known processes, both regarding the use of a more effective way to transfer heat to the load to be processed and the use of an amount of electric energy which is closer to the minimum energy required for the process, i.e. limited to the supply of energy to heat the material up to the processing temperature, only added of the excess energy required to compensate inherent energy losses such as through the furnace walls; and to provide a better use of the internal volume of the furnace, with the increase in loading capacity for a given volume of the furnace cavity.
The technique, apt to process metal scraps as well as drosses which are generated when the metal or alloy is kept in liquid state in the various operations involved in its industrialization, containing the metal or alloy to be recovered, is realized by means of the following process operating steps:
1. introducing the load, constituted by a material containing the metal or metal alloy to be recovered, into the rotary furnace;
2. heating of the material up to a temperature above the melting point of the metal or metal alloy to be recovered;
3. moving the material within the furnace, induced by the rotation or simple oscillation movement of the furnace, during and after the heating step, to separate the molten metal from the non-metallic solid residue;
4. removing the molten metal separated from the non-metallic solid residues; and
5. removing the residual non-metallic solid material.
With no use of melting salts, the invention presents the novelty of the load being heated up to a temperature above the melting point of the metal or non-ferrous alloy to be recovered (step 2). The heating step being accomplished by means of a substantially convective heat exchange, which is independent from the supply of external gas to the process for effects other than the sole control, when desired, of the internal atmosphere of the furnace.
Therefore, the furnace used has the following characteristics: it is constituted by a closed vessel having a revolution axis around which it may be turned or simply submitted to oscillating movement; the construction of the furnace presents the possibility of its revolution axis to rest above the horizontal plane or to be inclined above and below that plane; be preferably heated by means of a free burning convective arc, which is self-stabilized and generated by an electric discharge in continuous current and which, due to the adjustment of the tilting angle (α) of the rotation axis of the vessel and the quantity of material fed therein, may be established between one single electrode introduced into the furnace and the load fed therein or the bottom wall of the vessel built of electrically conducting material; preferably, the electrode operates as the cathode in the continuous current electric circuit and is introduced through the furnace door, preferably according to an eccentric or inclined axis with respect to the rotation axis of the furnace, located above it, and which can be displaced alongside its own axis to adjust the length of the arc.
Which respect to the polarity of the electrode and its positioning, other possible arrangements may involve the following: electrode operating as the anode in the continuous current electric circuit; electrode operating in alternate current superimposed to a low power, low flow rate pilot flame; positioning the electrode above or below the lengthwise rotation axis of the furnace.
Using only the gas that determines the internal atmosphere of the furnace, a strong gas circulation is induced by mechanisms that are proper of self-stabilized free burning arcs fed under continuous current. According to the invention, such an arc is established between a cathode in the form of a moving electrode introduced into the furnace and an anode preferably formed by the load itself kept in contact with the bottom of the vessel built of electrically conducting material which, on the other hand, is in permanent contact with a fixed external electrode through the steel framework of the furnace.
In other words, the heating process as used does not require the feeding of any external gas, and may work as such or just with minimum flow rate of gas introduced into the cavity of the furnace with the only and sole purpose of providing a given processing atmosphere, as per convenience. Depending on the quantity of material fed in and the inclination of the lengthwise axis of the furnace, the electrically conductive bottom lining may be exposed to the arc which, under this condition, will act as anode.
The heating by predominantly convective heat transfer, caused by gas circulation within the arc, happens more intensely at the contact region between the arc and the anode which, in the present furnace concept, is preferably constituted by the load. This condition results the formation of load regions which are heated above the average bulk temperature of the load, and which are referred to in the literature as hot spots. According to the construction and operating characteristics of the equipment object of the invention, conditions are created for the heated material in these regions to be continually displaced by the action of rotating movement of the furnace, either fully rotating or simply oscillating the vessel, thus providing temperature homogenization by conduction and convection heat transfer in the bulk of the load.
Although other fabricating materials may be used, according to the invention the electrode is preferably made of graphite. The following advantages are pointed out for using this material: the high strength of graphite under high temperatures; no need of using intense cooling means, as a matter of fact it may not be submitted to any kind of cooling at all; long term working life; graphite electrodes are constructively simple and easy to be replaced.
To improve the dissipation of the energy that concentrates in the arc attachment region in the anode, the preferred assembly of the electrode as introduced in the furnace follows an eccentric axis located above the rotation axis of the furnace. In comparison with the assembly of the electrode as aligned with the rotation axis of the furnace; this arrangement has the advantage of producing a relative movement of the load with respect to the region directly reached by the arc blow.
Being the case that the bottom of the vessel acts as anode, as previously stated this condition will depend on the tilting angle of the rotation axis and the amount of load introduced into the furnace, the eccentric assembly of the electrode over the rotation axis, combined with the continuous movement of the vessel, becomes particularly advantageous since it forces the region of the conducting refractory lining directly in contact with the arc blow to draw a circular path whose center lays over the rotation axis of the vessel in case of full turn, or simply an arc-like path in case of simple oscillation. In this case, the region of the bottom refractory strongly heated by convective heat transfer from the hot gases circulating through the arc may be cyclically cooled when it contacts the load at each cycle. At the beginning of the heating cycle this contact occurs mainly with solid material, and at later heating stages with the liquid metal precipitated to the bottom of the vessel. On the other hand, the load is continuously heated by its contact with the hotter bottom region that passes through the arc attachment.
In any condition, whether the anode function is played by the load or the electrically conducting bottom lining, the load's bulk temperature is controlled so not to surpass a specified processing temperature, according to the control of the power dissipated at the electric arc. Concurrent to the fast dissipation of the high energy transferred to the region into direct contact with the arc are both the convective heat transfer in the bulk of the load enhanced by the rotating movement of the vessel, and the high thermal conductivity characteristic of metals.
The physical principles of formation of self-stabilized free burning arcs are reviewed by S. E. Stenkvist and B. Bowman in High-Power, Graphite-Cathode DC Arc Plasma—Properties and Practical Applications for Steelmaking and Ferroalloys Processing in Plasma Technology in Metallurgical Processing, Iron and Steel Society, Inc., 1987, Chapter 8B, pages 103 to 109.
Particularly, the invention takes advantage of the electromagnetic pumping effect caused by the arc contraction which occurs at the interface between the fully developed arc and the cathode material, especially when the tip of the electrode is made sharp as, for example, when it is constructed with a conical geometry.
Concerning the treatment of scraps, a particularly preferred sequence of process operating steps involves keeping a molten metal heel over which one or more loads are effected. Therefore, depending on the apparent density and other characteristics of the material to be processed, step (1) may be repeated after step (3) one or more times, until the amount of load fed in a molten metal tapping cycle reaches a pre-determined value. In the same way, a fraction of the total liquid metal separated from the non-metallic solid residue in a tapping cycle may be kept within the furnace so to more easily promote the heating and melting of metal contained in new loads of material to be processed.
Although clean, previously prepared scraps, substantially lacking organic matter are preferably processed, particularly when dealing with contaminated scraps the repetition of the operating steps as above explained is preferably made onto overheated liquid metal. By moving the vessel to revolve the load, and not establishing the electric arc while the recently introduced load is heated, promotes the cleaning of the load by volatilizing the organics. Once the evolution of fumes ends, the arc is established and load temperature then raised to a specific value above the melting point of the metal or alloy being recovered.
In any loading condition, heating is controlled by knowing the amount of material fed, might it be the case the previous amount of material let into the furnace, monitoring of the power dissipated in the arc by recording the voltage and current of the arc, and monitoring of the temperature by means of thermocouples installed in the rotating vessel, preferably using a data acquisition system coupled to a microcomputer.
With the objective of providing a substantially inert processing atmosphere with respect to the metal to be recovered, particularly during the steps of melting and separation of the metal from non-metallic solid residues, a gas which does not react with the metal, preferably argon gas, may be introduced into the furnace chamber, through an axial hole produced at the center line of the electrode or at any other position of said chamber. In the same way, depending on the processed material, the processing step, and the desired processing effect, other gases may be introduced into the furnace chamber such as nitrogen, hydrogen, methane, carbon monoxide, carbon dioxide, oxygen, air or a mixture of these.
Despite the high temperatures of the gas blown by the arc, either towards the load or the bottom wall of the furnace; the average temperature of the process, which in case of aluminum scraps and dross may situates between 700° C. and 1000° C., is controlled by moderating the power dissipated in the arc, independently controlled by adjusting the current and voltage of the arc as a function of the process temperature, which preferably is continuously measured at the side wall of the furnace.
Once means to control the process atmosphere are provided—for example inhibiting atmospheric air to enter the processing chamber by appropriately sealing the vessel door, or producing a slightly positive internal pressure by feeding an inert gas such as argon in the furnace chamber—, and this atmosphere substantially lacks gases able to react with the metal—such as nitrogen and oxygen in case of aluminum, or volatile substances which may evolve while heating the load—, the establishment of an arc with the load is not a matter of major concern as in the description of other processes. On the contrary, according to the invention this resource constitutes an efficient mechanism through which, by simply controlling the intensity of the electric current as imposed to the arc by a power supply, great amounts of heat may be quickly and efficiently transferred directly to the load. As previously explained, both in case of loads with high free metal content, such as scrap, and loads with a considerable quantity of oxides, such as dross, the dissipation of the energy received by the material temporarily placed at the arc attachment region is carried out by continuously rotating or oscillating the vessel.
The invention allows to eliminate problems which are identified both in the processes using the energy released by burning fossil fuels and using plasma gas heaters or radiant electric arc as a way to heat the furnace and load on the purpose of metal recycling.
Concerning the processes in which rotary furnaces are heated by gas or oil burners, the present invention provides a less pollutant process to recover and recycle metals, since the proposed heating source allows the strict control of the process atmosphere and therefore dispenses with the use of melting salts.
Concerning the process that applies a plasma gas heater, the invention provides a process to recover and recycle non-ferrous metals using a rotary furnace that presents the following advantages: (a) considerable reduction in the volume of gas used in the process; (b) the use of lower volumes of gas directly results in the reduction of gaseous effluents which must be treated before being exhausted to the atmosphere; (c) the better control of the atmosphere as provided by the effective use of inert gases, such as argon—or not feeding gases at all—results in lower rates of metal losses by undesirable reactions, such as the reaction between aluminum and nitrogen forming aluminum nitride when using the latter as a plasma gas and, in the same way, by oxidation when using atmospheric air.
Concerning the higher metal yield which may be obtained, it is evident the advantage of using the convective arc as proposed in the present invention when compared with the use of plasma gas heater as the heating method. The heating of the load by convective arc may be quickly and effectively carried out only by using electric energy, without making use of the energy released by burning part of the recoverable metal, as it occurs when the plasma gas heater is operated with air.
Concerning the process in which the remelting furnace is heated with a radiating arc established between two electrodes placed above the rotation axis of the furnace, the invention presents the following advantages: (a) it provides a process to recover and recycle metals using rotary furnaces which is based on a more efficient heat transfer mechanism, since the convective arc principle as used allows to directly transfer heat from the arc to the load; (b) the formation of the convective electric arc using one single electrode positioned above the material to be processed allows to operate the furnace with its rotation axis inclined, with the loading door positioned above the horizontal line, which substantially reduces the risk of breaking the electrode as may be caused otherwise by its occasional contact with the processed material; (c) for a given volume of cavity, the tilting of the furnace rotation axis during operation, positioning the electrode well above the processed material, allows to increase the loading capacity, therefore allowing to increase the production rate without the need of a bigger and therefore more expensive equipment.
The heating of rotary furnaces with fossil fuel burners or plasma gas heater is mainly based on convective heat exchange which, to be effectively carried out, depends on a minimum residence time of the hot gases into the furnace. In practice, this means that a considerable fraction of the volume of the furnace cavity should be kept void, thus limiting the loading capacity the cavity. In case of using an electric arc transferred between two electrodes located at the axis of the furnace and above the load, such as in the case of the process introduced by the patents CA 2030727 and U.S. Pat. No. 5,245,627—whose predominant heat exchange mechanism is arc radiation—, since for operational reasons the furnace must be kept with its lengthwise axis fixed in the horizontal direction while heating and revolving the load into it, an even smaller fraction of the volume of the furnace cavity can be made available to be loaded with material.
In the case of the equipment object of the invention, since the heat transfer is predominantly due to convection and may, in practice, be carried out without introducing any gas into the furnace, there are not limitations either concerning free cavity volume to allow minimum residence times or avoiding the inclination of the rotation axis to prevent breaking of electrodes. Therefore, the invention results in loading capacities which may be substantially higher than previous processes. Mainly concerning materials of high content of free metal; such as in the case of most scraps which are previously prepared, the better occupation of the furnace chamber allows higher production rates over other available heating methods, for a same volume of the furnace chamber.
Despite the partial loss of the revolving effect of the load resulting from further tilting of the lengthwise axis of the furnace above the horizontal direction, the following observations contribute to a better and differentiated performance of the present invention with respect to rotary furnace heating technologies proposed so far: the reduced importance of the effect of revolving as the content of free metal present in the load increases; the fact that the heat transfer occurs directly to the load as the slope of the lengthwise axis of the furnace increases; higher rate of heat transfer, controlled by adjusting the intensity of the arc current, contributing to the quicker formation of a large volume of liquid metal which facilitates both the consolidation of the metal bath as a whole and the quicker and more effective heat transfer within the bulk of the load by liquid phase conduction and convection.

Process and equipment for the treatment of loads or residues of non-ferrous metals and their alloys

Fundacao de Amparo a Pesquisa do Estado do Sao Paulo-Fapesp

Instituto de Pesquisa Technologicas do Est. S. Paulo S/A-IPT


Acetone and phenol are reacted in the presence of an acid-type ion exchange resin. The reaction mixture obtained from the reaction is subjected to a reduced-pressure distillation to recover bisphenol A as a fraction discharged from the bottom of a distillation column. Before the reaction, the acid-type ion exchange resin is washed with phenol to produce a phenol solution. The phenol solution is distilled together with a fraction obtained from the top of a distillation column. The bisphenol A produced in the process exhibits a stable hue.

1. Field of the Invention
The present invention relates to a process for producing bisphenol A exhibiting a stable hue. The thus produced bisphenol A is useful as raw materials of polycarbonate resins, epoxy resins, polyarylate resins or the like.
2. Background Arts
As well known in the arts, bisphenol A [2,2-bis(4-hydroxyphenyl) propane] is an important compound useful as raw material of engineering plastics such as polycarbonate resins and polyarylate resins, or epoxy resins. Recently, the demand for the above compound tends to be more and more increased. In particular, when used as raw material of polycarbonate resins, the bisphenol A has been required to exhibit a stable hue without undesired coloration even when it is treated at an elevated temperature.
It is also known that the bisphenol A is produced by condensing phenol with acetone in the presence of an acid-type ion exchange resin as a catalyst. In this case, the acid-type ion exchange resin is usually swelled with water and packed in a reactor. After packing, the ion exchange resin is washed with water to remove acid substances therefrom, and then washed with phenol prior to its use in the reaction. Conventionally, the phenol used for the washing has been usually mixed with a reaction mixture discharged from outlet of the reactor in order to recover and purify the phenol. For this reason, the thus produced bisphenol A inevitably contains acid substances, resulting in deteriorated hue thereof.
The present invention has been made in view of the above problems. An object of the present invention is to provide a process for producing bisphenol A exhibiting a stable hue without undesired coloration even when treated at an elevated temperature.
As the result of extensive studies, the present inventors have found that the above object is achieved by removing acid substances from a phenol solution obtained after washing the acid-type ion exchange resin. The present invention has been accomplished based on this finding.
Thus, the present invention provides a process for producing bisphenol A by reacting acetone with phenol in the presence of an acid-type ion exchange resin as a catalyst and then subjecting the reaction mixture to a reduced-pressure distillation to recover the bisphenol A from a fraction discharged from a bottom of distillation column, comprising:
washing said acid-type ion exchange resin filled in a reactor with phenol before using the ion exchange resin in the reaction; and
distilling a phenol solution obtained after the washing together with a fraction obtained from a top of the distillation column for recovery of phenol.
The present invention will be described in detail below.
First, the respective steps of the process for the production of bisphenol A is described.
Step (1): Reaction Step
Bisphenol A is produced by reacting acetone with an excess amount of phenol in the presence of an acid-type ion exchange resin as catalyst and, if required, alkylmercaptan as co-catalyst. As the suitable acid-type ion exchange resin as catalyst, there may be generally used sulfonic acid-type cation exchange resins. Examples of such sulfonic acid-type cation exchange resins include sulfonated styrene divinyl benzene copolymers, sulfonated cross-linked styrene polymers, phenol formaldehyde-sulfonic acid resins, benzene formaldehyde-sulfonic acid resins or the like. These sulfonic acid-type cation exchange resins may be used alone or in the form of a mixture of any two or more thereof.
The suitable alkylmercaptan used as co-catalyst are such mercaptans having a C1-C10 alkyl group. Examples of the alkylmercaptans include methylmercaptan, ethylmercaptan, propylmercaptan, octylmercaptan, cyclohexylmercaptan or the like. Among these alkylmercaptans, ethylmercaptan is especially preferred. Meanwhile, these alkylmercaptans may be used alone or in the form of a mixture of any two or more thereof.
The above reaction may be desirably conducted by a fixed-bed continuous or batch method, though not limited thereto. When the reaction is conducted by fixed-bed continuous method, the liquid hourly space velocity (LHSV) used therein is usually in the range of 0.2 to 30 Hrxe2x88x921, preferably 0.5 to 6 Hrxe2x88x921.
As to the other reaction conditions, the reaction temperature is 60 to 100xc2x0 C.; the molar ratio of phenol to acetone is 6 to 13; and the molar ratio of acetone to mercaptan is 13 to 25.
The resultant reaction mixture contains, in addition to bisphenol A, unreacted phenol, unreacted acetone, catalysts, by-produced water, alkylmercaptan, and other by-products such as organic sulfur compounds and colored substances.
Step (2): Recovery of By-Produced Water and Unreacted Raw Materials
Then, the reaction mixture obtained in the step (1) is distilled under reduced pressure to remove unreacted acetone, by-produced water, alkylmercaptan, a part of unreacted phenol and the like from a top of distillation column and obtain a liquid mixture containing bisphenol A, phenol, etc., from the bottom thereof. The reduced-pressure distillation may be conducted at a temperature of 70 to 180xc2x0 C. under a pressure of 6.7 to 80.0 kPa. Upon such a distillation, the unreacted phenol is subjected to azeotropy, and removed out of the reaction system from the top of the distillation column.
Step (3): Concentration of Bisphenol A
The bottoms obtained by removing the above substances from the reaction mixture, is then distilled under reduced pressure to remove unreacted phenol therefrom and concentrate bisphenol A contained therein. The thus obtained concentrated residual solution is used as a raw material of the subsequent crystallization step. The concentration conditions are not particularly restricted, but the concentration process may be usually conducted at a temperature of 100 to 170xc2x0 C. under a pressure of 5.3 to 66.7 kPa. When the temperature is less than 100xc2x0 C., it is necessary to keep the reaction system under high vacuum condition. On the contrary, when the temperature is more than 170xc2x0 C., an additional heat-removal step is required upon conducting the subsequent crystallization step. The concentration of bisphenol A contained in the concentrated residual solution is in the range of 20 to 50% by weight, preferably 20 to 40% by weight. When the concentration of bisphenol A contained in the concentrated residual solution is less than 20% by weight, the recovery percentage of bisphenol A becomes lowered. On the contrary, when the concentration of bisphenol A in the residual solution is more than 50% by weight, it is difficult to transport a slurry obtained after the crystallization step.
Step (4): Crystallization
The concentrated residual solution obtained in the step (3) is cooled to a temperature of 40 to 70xc2x0 C. to crystallize an adduct of bisphenol A and phenol (hereinafter referred to merely as xe2x80x9cphenol adductxe2x80x9d), thereby obtaining a slurry. The cooling is conducted due to heat removal caused by evaporating water added to external heat exchanger and crystallizer. Next, the slurry-like concentrated residual solution is subjected to filtration, centrifugal separation, etc., and separated into the phenol adduct and a crystallization mother liquor containing by-products. The thus obtained crystallization mother liquor may be directly or partially recycled to the reactor, or recovered in the form of phenol and isopropenyl phenol by subjecting whole or part thereof to alkali decomposition. Alternatively, a part or whole of the crystallization mother liquor may be isomerized and recycled as raw material to the crystallization step (refer to Japanese Patent Laid-open No. 6-321834).
Step (5): Heat-Melting of Phenol Adduct
The 1:1 adduct of bisphenol A and phenol obtained in the step (4) in the form of crystals, is heat-melted at a temperature of 100 to 160xc2x0 C. to obtain a liquid mixture.
Step (6): Recovery of Bisphenol A
The liquid mixture obtained in the step (5) is distilled under reduced pressure to remove phenol and recover bisphenol A therefrom. The reduced-pressure distillation is conducted at a temperature of 150 to 190xc2x0 C. under a pressure of 1.3 to 13.3 kPa. In addition, the removal of residual phenol may be conducted by known methods such as steam-stripping.
Step (7): Granulation of Bispherol A
The molten bisphenol A obtained in the step (6) is formed into droplets using a granulating apparatus such as spray dryer, and cooled and solidified to obtain an aimed product. The droplets are produced by spraying, spreading or the like method, and cooled with nitrogen, air or the like.
In the present invention, the acid-type ion exchange resin filled in the reactor is washed with phenol before used in the reaction, and a phenol solution obtained after the washing (hereinafter referred to merely as a xe2x80x9cwashing phenol solutionxe2x80x9d) is distilled together with a fraction (containing acetone, by-produced water, phenol and alkylmercaptan) obtained from a top of the reduced-pressure distillation column used in the above step (2) to recover phenol therefrom and recycle the recovered phenol. In the distillation, only one distillation column may be used to separate the mixture into respective components by varying the distillation conditions. Alternatively, several distillation columns may be used to separate the mixture into respective components. The washing phenol solution and the fraction obtained from the top of the above reduced-pressure distillation column may be continuously or intermittently mixed together. In any case of the continuous and intermittent mixing methods, the distillation may be conducted in such a manner that the ratio of phenol contained in the washing phenol solution to that recovered from the fraction obtained from the top of the reduced-pressure distillation column is within the range of 1:0.01 to 1:2.
The thus recovered phenol contains no acid substances and is therefore reusable as the raw material.
Meanwhile, the washing phenol solution may be temporarily stored before use.
Next, the process of the present invention will be described in more detail below. However, these examples are only illustrative and not intended to limit the present invention thereto.


An article and method for stabilizing a rock chip. The article in one embodiment of the invention includes a laminar rock chip substantially surrounded by and imbedded within a plug having a solid material, the plug forming a top planar surface and a bottom planar surface substantially parallel with the top planar surface, the laminar rock chip forming a contact surface portion exposed at the top planar surface of the plug, a laminar plane of the laminar rock chip being substantially perpendicular with the top planar surface.

In preparing for the stimulation of production of oil and gas wells, e.g., hydraulic fracturing, observing and testing core samples provide operators with useful geologic information regarding the formation through which the well bore is formed. An operator at the well site may collect the core samples and either perform field tests or send the samples to an off-site location for analysis. When analyzing the samples, different properties of the rock may be determined, including the hardness of the rock. In order to test the hardness of a rock, typically a technician will place the rock sample in a hardness tester and apply an indenter to the surface of the rock sample parallel to the laminar plane of the rock sample to determine the hardness of the rock sample. Typical rocks found in production stimulation include sandstone, limestone, shale, dolomite, and the like.

Article and method for stabilizing a rock chip


A vehicle includes one or more microphones that are each configured to selectively provide sound signals from one or more seating positions in the vehicle. A controller is programmed to receive an input indicative of a request to enter a group conversation mode upon initiation of a call, and, responsive to receiving the input, enable the microphones to selectively provide sound signals from all of the seating positions.

Modern vehicles are expected to provide voice capability for a variety of functions. For example, mobile telecommunications and handsfree vehicle functions require voice inputs to operate. Vehicles typically include a communication system that is optimized for the driver. Such systems provide limited performance for other passengers as the voice interface is optimized for the driver position. Voice signals from other seating positions are attenuated and cannot be heard clearly through the communication link.


Photonic integrated circuit (PIC) chips with backside vertical optical coupler and packaging into an optical transmitter/receiver. A grating-based backside vertical optical coupler functions to couple light to/from a plane in the PIC chip defined by thin film layers through a bulk thickness of the PIC chip substrate to emit/collect via a backside surface of the PIC chip where it is to be coupled by an off-chip component, such as an optical fiber. Embodiments of a grating-based backside vertical optical coupler include a grating coupler with a grating formed in a topside surface of the thin film A reflector is disposed over the grating coupler to reflect light emitted from the grating coupler through the substrate to emit from the backside of the PIC chip or to reflect light collected from the backside of the PIC chip through the substrate and to the grating coupler.

Monolithically integrated photonic circuits are useful as optical data links in applications such as, but not limited to, optical communications, high performance computing and data centers. For mobile computing platforms too, a PIC is a useful means of I/O to rapidly update or sync a mobile device with a host device and/or cloud service where a wireless link has insufficient bandwidth. Such optical links utilize an optical I/O interface that includes an optical transmitter and an optical receiver. One challenge with the optical I/O interface is coupling light between monolithically integrated photonic circuits, which are fabricated on a micrometer scale, and separately packaged components (e.g., optical fiber, etc.) which are assembled on the millimeter scale. A PIC may utilize vertical or edge-based optical I/O coupling techniques. The edge coupling technologies have a substantial drawback in that device testing requires an edge to be provided, typically by singulating the substrate upon which the PIC was fabricated into individual PIC chips. The vertical coupling technologies, while advantageously amenable to "wafer-level" PIC testing, typically have lower coupling efficiency than do the edge technologies. For example, a surface coupled PIC may have an emission efficiency in the range of about 50%.
Another limitation with vertical coupling techniques is that the presence of optical I/O on a top side of the PIC is generally incompatible with advanced flip-chip or controlled collapse (C4) packaging techniques in which the top side of an IC is affixed to a package substrate (e.g., by bumps and solder balls). For such flip-chip techniques, it is difficult to provide a package substrate that doesn't occlude the vertical optical coupling.
As such, a vertical coupling technique that offers improved coupling efficiency and is amendable to flip-chip packaging would be highly advantageous in the provision of PICs, such as optical transmitters.

Efficient backside-emitting/collecting grating coupler


A catheter hub assembly. The catheter hub assembly includes a catheter hub body, a septum and a septum retainer, the catheter hub body having a distal end, a proximal and an internal wall defining an internal fluid passageway therebetween, the internal wall defining a transitional step within the internal fluid passageway, the septum positioned within the internal fluid passageway such that a distal end of the septum abuts up against the transitional step, the septum retainer at least partially receivable within the internal fluid passageway and having an outer wall shaped and sized to interlock with the inner wall of the catheter hub body, the outer wall including one or more lateral ribs configured to inhibit rotation of the septum retainer relative to the catheter hub body.

Intravenous (IV) therapy is a versatile technique used for the administration of medical fluids to and withdrawal of bodily fluids from patients. IV therapy has been used for various purposes such as the maintenance of fluid and electrolyte balance, the transfusion of blood, the administration of nutritional supplements, chemotherapy, and the administration of drugs and medications. These fluids, collectively referred to herein as medicaments, may be administered intravenously by injection through a hypodermic needle, or intermittently or continuously by infusion using a needle or catheter. A common intravenous access device utilized by clinicians is the peripheral IV catheter.
A peripheral IV catheter is made of soft, flexible plastic or silicone, generally between fourteen to twenty-four gauge in size. In the conventional venipuncture procedure, a catheter is inserted into a vein in the patient's hand, foot, or the inner aspect of the arm or any vein in the body that will accept an IV catheter. In order to place the IV catheter into a patient's vein, a sharp introducer needle is used to puncture the skin, tissue, and vein wall to provide a path for placement of the catheter into the vein.
Referring to FIGS. 1A-B, a conventional IV needle assembly 50 configured for insertion of an "over the needle" catheter 52 is depicted. Catheter 52 generally includes a catheter tube 54 having a distal end 56 for insertion into a biological site, a proximal end 58 and a flexible wall defining a lumen extending therebetween. Frequently, the proximal end 58 of the catheter tube 54 is operably coupled to a catheter hub 60. Catheter 52 can be operably coupleable to the needle assembly 50, in part by positioning the catheter 52 coaxially over a needle 62 of the needle assembly 50. The catheter 52 thus rides with the needle 62 through the skin, tissue and vein wall and into the patient's vein. Once the catheter tube 54 has been entered into the patient's vein, the catheter 52 can be advanced further into the vein as desired and the needle 62 can be withdrawn from the catheter 52. The catheter 52 can then be secured into place on the patient and connected to an IV fluid supply. In some instances, catheter 52 can include an extension tube 64 having a clamp 66 and a Luer lock connector 68 for connection to an IV fluid supply. Such catheters are often referred to as closed system catheters, as typically they include a septum that seals the needle path after the needle 62 has been withdrawn from the catheter 52, thereby preventing blood or bodily fluid from the patient from escaping from the catheter to the ambient environment.


A handle assembly mountable on a valve is disclosed. The assembly includes a head having a receptacle engageable with a rotatable shaft on the valve and a grip projecting outwardly from the head to facilitate turning of the head for actuating the valve. An arcuate slot is positioned in the head, the slot having a curvature matched to the arcuate motion of the handle when used to turn the valve shaft. A limit post is attached to the valve and projects through the slot. A jam nut is mounted on the post adjacent to the head. When tightened against the head the jam nut fixes the position of the head relatively to the valve. A bolt is positioned within the slot and retained by a nut. The bolt is movable along the slot to a predetermined position where it can be temporarily fixed by tightening the nut. The bolt acts as a memory stop when it engages the limit post as the head is turned.

Devices such as valves for fluid control are often actuated and adjusted manually in industrial installations in the course of operation of various industrial processes such as petroleum refining, paper manufacture, mining, chemical production and waste water treatment plants to cite but a few examples. Manual adjustment of valves allows the industrial processes controlled by the fluid flow through the valves to be optimized for various factors such as product yield, throughput, reaction rate, as well as other parameters associated with the economics and efficiency of the processes.
It is desirable to incorporate refinements into the valve design that will allow for convenient setting of the valves to known positions providing fluid flow rates determined either theoretically or during operation of the industrial processes that produce the desired yield, reaction rate, throughput or other process parameters. Infinite variability of the setting is advantageous for precise tuning of system parameters.
Additional desirable refinements to valves also include the ability to lock the valve in the closed or open positions. Locking the valve in the closed position will help prevent mishaps during system maintenance, when portions of the system may be disassembled for replacement or repair. Locking the valve in the open position will help ensure that fluid flow is not halted inadvertently during operation. It is also advantageous to have the valve be tamper resistant to prevent unauthorized opening of the valve and thereby prevent theft of the product flowing through the system. The aforementioned refinements for devices such as valves may be effected using handle assemblies as described and claimed below.


The invention relates to OCT-3 polypeptides, nucleic acid molecules encoding OCT-3, and uses thereof. OCT-3 is a protein that is expressed in the plasma membrane of biological cells, across which it regulates the transport of organic molecules.

In the course of performing their normal physiological functions, many types of cells, including bacterial cells and those in specialized mammalian tissues such as the liver and kidney, transport a variety of organic molecules across their cell membranes. For example, cells in the proximal tubule of the kidney transport glucose, amino acids, and uric acid across their membranes, and work to eliminate various drugs and toxic substances from the body. All of these molecules are transported across the cell membranes by specialized cellular transporters.
Recently, genes encoding several putative transporters have been identified. These molecules include OCT-1 (organic cation transporter; Grundemann et al., Nature 372:549-552, 1994), OCT-2 (Okuda et al., Biochem. Biophys. Res. Comm. 224:500-507, 1996), NLT (novel liver-specific transporter; Simonson et al., J. Cell Sci. 107:1067-1072, 1994), and NKT (novel kidney-specific transporter; Lopez-Nieto et al., J. Biol. Chem. 272:6471-6478, 1997). While the sequences of these transporters are not highly conserved (at the amino acid level, OCT-1 and NLT are only 30% and 35% identical to NKT, respectively), they do exhibit similar transmembrane (TM) domain hydropathy profiles.
The invention described herein relates to the discovery and characterization of oct-3, a gene encoding a protein that transports molecules across the plasma membranes of biological cells. OCT-3 is highly expressed in the neuronal cells of the brain, including, e.g., cells in the cortex and in the hypothalamus. Accordingly, altering the expression or activity of OCT-3 (e.g., with small molecules, antisense molecules, or neutralizing antibodies) can alter the concentration of molecules (such as neurotransmitters) that are present within the cell or in the extracellular spaces around the cell (i.e., on either side of the plasma membrane). Altering the concentrations of these molecules in patients afflicted with certain conditions, including neurodegenerative diseases, behavioral disorders, eating or sleep disorders, and pain responses (e.g., elicited during various forms of tissue injury or in association with musculoskeletal disorders), can provide relief from the symptoms associated with these conditions.
More specifically, the invention features an isolated nucleic acid molecule (i.e., a nucleic acid molecule that is separated from the 5xe2x80x2 and 3xe2x80x2 coding sequences with which it is immediately contiguous in the naturally occurring genome of an organism) that encodes an OCT-3 polypeptide. As used herein, an OCT-3 polypeptide is a polypeptide that: (1) is expressed in the plasma membrane of a biological cell (e.g., a cell in the kidney, liver, or brain), (2) contains transmembrane (TM) domains, and (3) when functioning normally, transports organic molecules across the plasma membrane. Preferably, the OCT-3 polypeptide has at least 6 transmembrane domains (e.g., 6, 8, or 10 TM domains), and more preferably, has at least 12 TM domains. The OCT-3 polypeptide can be a mammalian polypeptide, i.e., a polypeptide normally expressed by the cells of a mammal, such as a human. In the event the OCT-3 polypeptide is human, it can have the sequence shown in 2 or SEQ ID NO:4, or it can be encoded by nucleic acid molecules having the sequence shown in SEQ ID NO:1 or SEQ ID NO:3. However, the invention is not limited to nucleic acid molecules and polypeptides that are identical to those SEQ ID NOs. For example, the invention includes nucleic acid molecules which encode splice variants, allelic variants or mutant forms of OCT-3 as well as the proteins encoded by such nucleic acid molecules. Also within the invention are nucleic acid molecules that hybridize under stringent conditions to a nucleic acid molecule having the sequence of SEQ ID NOs:1, 3, or 5. As described further below, molecules that are substantially identical to SEQ ID NOs:1-6 are also encompassed.
The term xe2x80x9csubstantially purexe2x80x9d as used herein in reference to a given compound (e.g., an OCT-3 polypeptide) means that the compound is substantially free from other compounds, such as those in cellular material, viral material, or culture medium, with which the compound may have been associated (e.g., in the course of production by recombinant DNA techniques or before purification from a natural biological source). When chemically synthesized, a compound of the invention is substantially pure when it is substantially free from the chemical compounds used in the process of its synthesis. Polypeptides or other compounds of interest are substantially free from other compounds when they are within preparations that are at least 60% by weight (dry weight) the compound of interest. Preferably, the preparation is at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight the compound of interest. Purity can be measured by any appropriate standard method, for example, by column chromatography, polyacrylamide gel electrophoresis, or HPLC analysis.
Where a particular polypeptide or nucleic acid molecule is said to have a specific percent identity to a reference polypeptide or nucleic acid molecule of a defined length, the percent identity is relative to the reference polypeptide or nucleic acid molecule. Thus, a peptide that is 50% identical to a reference polypeptide that is 100 amino acids long can be a 50 amino acid polypeptide that is completely identical to a 50 amino acid long portion of the reference polypeptide. It might also be a 100 amino acid long polypeptide which is 50% identical to the reference polypeptide over its entire length. Of course, many other polypeptides will meet the same criteria. The same rule applies for nucleic acid molecules.
For polypeptides, the length of the reference polypeptide sequence will generally be at least 16 amino acids, preferably at least 20 amino acids, more preferably at least 25 amino acids, and most preferably 35 amino acids, 50 amino acids, or 100 amino acids. For nucleic acids, the length of the reference nucleic acid sequence will generally be at least 50 nucleotides, preferably at least 60 nucleotides, more preferably at least 75 nucleotides, and most preferably at least 100 nucleotides (e.g., 150, 200, 250, or 300 nucleotides).
In the case of polypeptide sequences that are less than 100% identical to a reference sequence, the non-identical positions are preferably, but not necessarily, conservative substitutions for the reference sequence. Conservative substitutions typically include substitutions within the following groups: glycine and alanine; valine, isoleucine, and leucine; aspartic acid and glutamic acid; asparagine and glutamine; serine and threonine; lysine and arginine; and phenylalanine and tyrosine.
Sequence identity can be measured using sequence analysis software (e.g., the Sequence Analysis Software Package of the Genetics Computer Group, University of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wis. 53705), with the default parameters as specified therein.
The invention also features a host cell that includes an isolated nucleic acid molecule encoding OCT-3 (either alone or in conjunction with a heterologous polypeptide, such as a detectable marker), or a nucleic acid vector that contains a sequence encoding OCT-3 (again, with or without a heterologous polypeptide). The vector can be an expression vector, and can include a regulatory element.
An antibody that specifically binds an OCT-3 polypeptide is also within the scope of the present invention and is useful, for example, to detect OCT-3 in a biological sample, or to alter the activity of OCT-3. For example, OCT-3 can be detected in a biological sample by contacting the sample with an antibody that specifically binds OCT-3 under conditions that allow the formation of an OCT-3-antibody complex and detecting the complex, if present, as an indication of the presence of OCT-3 in the sample. The use of an antibody in a treatment regime, where it can alter the activity of OCT-3, is discussed further below.
An antibody of the invention can be a monoclonal, polyclonal, or engineered antibody that specifically binds OCT-3 (as described more fully below). An antibody that xe2x80x9cspecifically bindsxe2x80x9d to a particular antigen, for example, an OCT-3 polypeptide of the invention, will not substantially recognize or bind to other molecules in a sample, such as a biological sample, that includes OCT-3.
Given that an object of the present invention is to alter the expression or activity of OCT-3 in vivo, a pharmaceutical composition containing, for example, an isolated nucleic acid molecule encoding OCT-3 (or a fragment thereof), a nucleic acid molecule that is antisense to OCT-3 (i.e., that has a sequence that is the reverse and complement of a portion of the coding strand of an OCT-3 gene), an OCT-3 polypeptide, or an antibody, small molecule, or other compound that specifically binds an OCT-3 polypeptide is also a feature of the invention.
The discovery and characterization of oct-3 and the polypeptide it encodes makes it possible to determine whether a given disorder is associated with aberrent expression of oct-3 (meaning expression at the level of gene transcription or mRNA translation) or activity of OCT-3. For example, one can diagnose a patient as having a disorder associated with aberrant expression of oct-3 by measuring oct-3 expression in a biological sample obtained from the patient. An increase or decrease in oct-3 expression in the biological sample, compared with oct-3 expression in a control sample (e.g., a sample of the same tissue collected from one or more healthy individuals) indicates that the patient has a disorder associated with aberrant expression of oct-3. Similarly, one can diagnose a patient as having a disorder associated with aberrant activity of OCT-3 by measuring OCT-3 activity in a biological sample obtained from the patient. An increase or decrease in OCT-3 activity in the biological sample as compared with OCT-3 activity in a control sample, indicates that the patient has a disorder associated with aberrant activity of OCT-3. The techniques required to measure gene expression or polypeptide activity are well known to those of ordinary skill in the art.
In addition to diagnostic methods, such as those described above, the present invention encompasses methods and compositions for typing and evaluating the prognosis, appropriate treatment, and treatment effectiveness of disorders associated with inappropriate expression of oct-3 or inappropriate activity of OCT-3. For example, the nucleic acid molecules of the invention can be used as probes to classify cells in terms of their level of oct-3 expression, or as primers for diagnostic PCR analysis in which mutations, allelic variations, and regulatory defects in the oct-3 gene can be detected. Similarly, those of ordinary skill in the art can use routine techniques to identify inappropriate activity of OCT-3, which can be observed in a variety of forms. For example, inappropriate activity can take the form of an alteration in the rate with which an OCT-3 transporter moves molecules across the plasma membrane, or a difference in the type of molecule that is transported. Diagnostic kits for the practice of such methods are also provided.
The invention further encompasses transgenic animals that express an oct-3 gene and recombinant xe2x80x9cknock-outxe2x80x9d animals that fail to express an oct-3 gene. These animals can serve as new and useful models of disorders in which oct-3 is misexpressed.
The invention also features antagonists and agonists of OCT-3 that can inhibit or stimulate, respectively, one or more of the biological activities of OCT-3. Suitable antagonists can include small molecules (i.e., organic or inorganic compounds with a molecular weight less than about 10,000 grams per mole), large molecules (i.e., molecules with a molecular weight greater than about 10,000 grams per mole), antibodies that specifically bind and xe2x80x9cneutralizexe2x80x9d OCT-3 (as described below), and nucleic acid molecules that interfere with transcription or translation of OCT-3 (e.g., antisense nucleic acid molecules and ribozymes). Agonists of OCT-3 also include small and large molecules, and antibodies other than neutralizing antibodies.
The invention also features molecules that can increase or decrease the expression of oct-3 (e.g., by altering transcription or translation). Small molecules (as defined above), large molecules (as defined above), and nucleic acid molecules (e.g., antisense and ribozyme molecules) can be used to inhibit the expression of an oct-3 gene. Other types of nucleic acid molecules (e.g., molecules that bind to oct-3 transcriptional regulatory sequences) can be used to increase the expression of an oct-3 gene.
Compounds that modulate the expression of oct-3 in a cell can be identified by comparing the level of expression of oct-3 in the presence of a selected compound with the level of expression of oct-3 in the absence of that compound. A difference in the level of oct-3 expression indicates that the selected compound modulates the expression of oct-3 in the cell. A comparable test for compounds that modulate the activity of OCT-3 can be carried out by comparing the level of OCT-3 activity in the presence and absence of the compound.
Patients who have a neurological disorder mediated by abnormal OCT-3 activity can be treated by administration of a compound that alters the expression of the oct-3 gene or the activity of the OCT-3 protein. When the objective is to decrease expression or activity, the compound administered can be an oct-3 antisense oligonucleotide, an antibody, such as a neutralizing antibody, or an antagonist that specifically binds oct-3 or OCT-3, respectively.
A wide variety of OCT-3 mediated neurological disorders are amenable to treatment according to the methods set forth herein. For example, the neurological disorder can be a neurodegenerative disease, such as Parkinson""s Disease, Huntington""s Disease, or Alzheimer""s Disease. Alternatively, the neurological disorder can be characterized by abnormal behavior or mood disorders. For example, the patient may suffer from depression, anxiety, or schizophrenia. A patient who has a sleep disorder or a weight disorder, such as a patient who is obese or who is suffering from a wasting disorder (as often occurs in the event of AIDS) can also be treated by administration of a compound that alters the expression of oct-3 or the activity of OCT-3. The neurological disorder can be pain, e.g., pain response elicited during various forms of tissue injury, e.g., inflammation, infection, and ischemia, usually referred to as hyperalgesia (described in, for example, Fields, H. L. (1987) Pain, New York:McGraw-Hill), pain associated with musculoskeletal disorders, e.g., joint pain; tooth pain; headaches; and pain associated with surgery, rheumatoid arthritis, viral infection, allergic reaction, asthma, chronic pain, chronic pancreatitis, somatoform disorders, fibromyalgia syndrome; and neuropathic pain, allodynia, and hyperesthesia. A detailed description of these methods of treatment is set forth below.
The preferred methods and materials are described below in examples which are meant to illustrate, not limit, the invention. Skilled artisans will recognize methods and materials that are similar or equivalent to those described herein, and that can be used in the practice or testing of the present invention.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In addition, the materials, methods, and examples are illustrative only and are not intended to be limiting.
Other features and advantages of the invention will be apparent from the detailed description and from the claims.

Methods of using transporter-like molecules to treat pain and pain-related disorders


A gasket for a manifold seal for a fuel cell system includes a first layer of fibrous ceramic material having a first compressibility, a second layer of fibrous ceramic material having a second compressibility and a third layer of fibrous ceramic material having third compressibility. The third layer of fibrous ceramic material is positioned between and engaged with the first layer of fibrous ceramic material and the second layer of fibrous ceramic material. The third compressibility is less than the first compressibility and less than the second compressibility.

A fuel cell is a device which uses an electrochemical reaction to convert chemical energy stored in a fuel such as hydrogen or methane into electrical energy. In general, fuel cells include an anode to catalytically react with the fuel and a cathode in fluid communication with an oxidant such as air.
Fuel cells are typically arranged in a stacked relationship. A fuel cell stack includes many individual cells positioned between a fixed end plate and a free end plate. One fuel cell stack configuration includes an externally manifolded stack, wherein the fuel cell stack is left open on its sides and a fluid such as a fuel or oxidant is delivered by way of manifolds sealed to peripheral portions of respective sides of the fuel cell stack. The manifolds thus provide sealed passages for delivering the fuel and the oxidant gases to the fuel cells and directing the flow of such gases in the stack, thereby preventing those gases from leaking either to the environment or to the other manifolds. Such manifolds are typically used in Molten Carbonate Fuel Cells (MCFC) which operate at approximately 650° C. During operation of MCFCs, the fuel cells can move relative to the end plates.
Conventional fuel cells typically include an anode and a cathode separated by an electrolyte contained in an electrolyte matrix. The anode, the cathode, the electrolyte and the electrolyte matrix are disposed between a first collector and a second collector, with the first collector adjacent to the anode and the second collector adjacent to the cathode. Fuel flows to the anode via the first collector and an oxidant flows to the cathode via the second collector. The fuel cell oxidizes the fuel in an electrochemical reaction which releases a flow of electrons between the anode and cathode, thereby converting chemical energy into electrical energy.
The fuel cells described above can be stacked in series with separator plates disposed between adjacent fuel cells and end plates (e.g., a fixed end plate and a free end plate) disposed on opposing ends of the fuel cell stack. Fuel cells are stacked to increase the electrical energy they produce. Fuel cell stacks have a negative side with a negative end cell and a positive side with a positive end cell.
Ceramic materials such as sheets and fabrics comprised of ceria (CeO2), zirconia (ZrO2) and alumina (Al2O3) have been used in high temperature sealing and refractory applications. In particular, such ceramic materials have been used to manufacture conventional gaskets for wet and/or dry sealing of various high temperature fluids. However, such conventional gaskets are pliable and tend to sag when handled or otherwise manipulated during an assembly process. In addition, conventional gaskets have relatively low compressive strength. For example, conventional gaskets can irreversibly crush and achieve a strain of almost 0.9 in/in, when subject to a relatively low compressive load, thereby degrading the gaskets' sealing performance.
Gaskets made from ceramic materials have also been used in various fuel cell applications. A problem sometimes experienced by liquid phase fuel cells such as MCFCs is electrolyte migration which is characterized by the loss of the electrolyte from the positive end cell and the gain of electrolyte by the negative end cell. Electrolyte migration is caused by an electric voltage gradient along the length of the stack and generated by the cells in the MCFC stack. Loss of the electrolyte from the positive end cells can cause gas pockets in the electrolyte matrix of the positive end cell. This results in an irreversible increase in internal electrical resistance causing a significant voltage drop across the positive end cell and therefore decreasing the useful life of the MCFC stack. Migration of the electrolyte towards the negative end cell can also cause the negative end cell to become flooded with electrolyte, thereby reducing MCFC stack performance and life.
Electrolyte migration can occur because the electrolyte is a molten liquid when the MCFC is at its operating temperature, for example, as discussed in U.S. Pat. Nos. 8,088,697 and 7,294,427. Thus during operation, when the electrolyte is liquid, the electrolyte can flow along an outer surface of the MCFC stack. In particular, the electrolyte can flow in and/or under a gasket disposed between the outer surface and a manifold used to channel fluid such as fuel and air to the fuel cell. Problems with conventional ceramic gaskets (e.g., felts of zirconia, alumina and ceria) used for liquid phase fuel cells include: absorbing high amounts of electrolyte, acting as a conduit for electrolyte movement and having low strength. The low strength of these materials makes them difficult to handle and install in fuel cells. Ceramic gaskets such as those consisting of ZYF100 zirconia felt manufactured and as received from by Zircar Zirconia, Inc. of Florida, N.Y. have been used as a material for MCFC gaskets. However, such gaskets typically cause performance problems associated with electrolyte migration and have poor mechanical properties (e.g., low compressive strength and significant sag).
Attempts have also been made to identify ceramic gasket materials with reduced electrolyte absorption to reduce electrolyte migration in MCFCs. However, the conventional zirconia and alumina gasket materials have high electrolyte absorption and undesirable migration rates. Furthermore, alumina is shown to be unstable and reacts with molten alkali carbonate electrolyte to form wettable LiAlO2.

Gasket for fuel cell system manifold seal


A pet ramp having a frame with flexible material mounted on the frame. The ramp is intended to be inclined against and supported at its top end by a bed. A first anchoring means, in the form of a flap of material extending from the frame, is provided for securing the frame to the bed, while a second anchoring means, in the form of high friction cups on the ends of the frame engaging the floor, secures the bottom end of the frame against slippage. The flap slips between a mattress and a box spring of the bed and is securely held there, so the frame will not move.

Household pets, such as dogs, can often be creatures of habit. They may have their favorite toy, but especially can have their favorite place to sleep. Unfortunately, this place may not always be where the owner would like it. If the owner wishes to train the pet to a particular place, they can put a soft cushion there and hope, or keep the pet there each night, until he learns to go by himself. Regardless of the method, however, the training must start when the pet is as young as possible. Once fully grown, new tricks become hard to teach.
Some pet owners wish to have their pets sleep in the same bed with them, for reasons including warmth, companionship or security. It therefore becomes important for these owners to train their pets early in life to sleep in the bed. If not, the pet may stay in the bed for a time, but will at some point in the night return to the favorite spot he has become accustomed to favor.
The problem arises when a young pet, such as a puppy, must be trained to climb onto a bed that is too high and physically impossible to climb. Once the dog has grown, he will be able to jump onto the bed with no difficulty, but beginning the training then would be too late. Additionally, smaller breeds of dogs may never achieve the necessary size and older, disabled or injured pets may find it impossible to jump onto the bed. It is thus necessary to provide a means for allowing the pet to climb onto the bed.
A common device for allowing animals to reach different heights are ramps. This type of ramp has usually taken the form shown in U.S. Pat. No. 3,618,568, wherein a pet house is disclosed having a ramp as an entrance means. The ramp is a hinged plank of solid material, such as wood, and includes added steps or slats to provide traction for the pet as he climbs the ramp.
It is possible to provide such a ramp for a bed, although impractical. The ramp would be quite heavy, making it a nuisance to install or store. Without any attachment means to the bed, the ramp's own weight would cause it to slide and fall. The size of the ramp, even though it is possible to fold it, as in U.S. Pat. No. 3,618,568, makes it cumbersome to store when the owner would not want it seen.
Thus, it is an object of the invention to provide a device that allows a pet to easily ascend onto a bed.
It is another object of the invention to provide a device that is securely attached to the bed.
It is a further object of the invention to provide a device that is easily and inexpensively manufactured, easily assembled, collapsible and portable.


An anchoring device for use within a vascular structure includes a head having a first surface and a second surface meeting at a common plane, and an anchor including a shaft having a longitudinal axis, a first end connected at a junction to the first surface of the head, and a free end. A harbor space is bounded by the shaft of the anchor, the first surface of the head, a first theoretical plane perpendicular to the longitudinal axis at a spaced distance from the junction and a second theoretical plane tangential to the head at a point in the common plane. The harbor space has an are sufficient to receive a portion of a stented device therein.

Heart valve disease may either be congenital or develop over a period of time and often materializes without notice. Where possible, patients are monitored and instructed to make lifestyle changes. However, where the function of the valve becomes significantly impaired, the only option may be heart valve replacement or repair.
There are two general types of heart valve replacement procedures. The first type is surgical replacement where the patient is placed on a heart and lung machine to undergo open heart surgery. The heart is stopped so that the diseased valve may be surgically removed and replaced by a prosthetic valve sutured into the same general location. This type of procedure is often the first consideration because of its long-term efficacy. However, open heart surgery is highly invasive and includes many attendant risks with the potential to be very severe or life threatening. Aside from the physical trauma of invading one of the most crucial areas of the human body, the risks are compounded by the heart and lung machine, which, among other things, can damage red blood cells leading to neurological deficiencies.
Due to these attendant risks, surgical valve replacement may not be a viable option, particularly for the elderly and frail. Additionally, individuals who receive surgical replacements earlier in life may need to have a follow-up replacement, which would likely be performed at an age where open heart surgery may be too risky. Thus, transcatheter valve implantation may be the best approach as the other type of heart valve replacement procedure. Transcatheter valve implantation is generally achieved by guiding a catheter, which retains an expandable prosthetic valve, through a patient's cardiovascular system to the diseased valve. The prosthetic valve is deployed such that the diseased valve is pushed out of the way so that the prosthetic valve can take over. Expandable prosthetic valves are primarily comprised of porcine or bovine tissue that is sewn to a stent that includes struts forming individually expandable cells. The stent may be made from a memory metal material, such as Nitinol, which gives it a natural bias toward an expanded state in order to hold the prosthetic valve in place.
Transcatheter valve implantation is currently indicated only for patients with severe stenosis. The primary reason for this limitation is valve migration. While the natural bias of the stent helps exert significant radial force against the surrounding soft tissue, this radial force typically is not enough to counteract the force of the flow of blood and gyrations from the beating heart. Thus, transcatheter valve implantation is indicated only for severe cases of stenosis so that the stent has a stable anchoring structure, such as calcium build-up, along the soft tissue of the native heart valve.
Consequently, there is a large segment of individuals who suffer from a valvular disease that requires valve replacement but who may not qualify for surgical replacement or transcatheter valve implantation. Therefore, there is a need for technology that would provide a stable anchoring platform for a transcatheter valve prosthesis in order to address the problem of migration so that a wider array of individuals may be effectively treated.

Anchoring studs for transcatheter valve implantation

St. Jude Medical, Cardiology Division, Inc.


Disclosed are compositions and methods for modulating oxidative and/or endoplasmic reticulum (OER) stress. More particularly, the present invention discloses compositions and methods that target OER stress inhibitors to pancreatic cells for treating diseases associated with oxidative and/or OER stress, including metabolic disorders such as diabetes.

Diabetes has rapidly developed into a major global epidemic. In 2011 it was announced that 336 million people worldwide suffer from type 2 diabetes, and this number is expected to grow to around 552 million by 2030. Currently, the disease is responsible for approximately 4.6 million deaths each year (Diabetes Atlas published by the International Diabetes Federation). Such a high number of instances is creating an unsustainable financial burden to healthcare systems, with treatment circulating over USD$465 billion dollars in 2011, which is a significant 11% of total healthcare expenditure in adults.
Despite current therapies, around 40% of individuals with type 2 diabetes develop a requirement for exogenous insulin administration over time, suggesting that these insulin secretory abnormalities progress after the onset of the disease. Accordingly, there is an obvious and clear need to develop more effective therapies for the treatment of type 2 diabetes, that improve the quality and/or quantity of insulin production, to address this gap in the current treatments.
Pancreatic β-Cell Insulin Secretion
Glucose-induced insulin secretion by pancreatic β-cells is generally schematized by a 'consensus model' that involves the following sequence of events: acceleration of glucose metabolism; closure of ATP-sensitive potassium channels (KATP channels) in the plasma membrane; depolarization, influx of Ca2+ through voltage-dependent calcium channels and a rise in cytosolic-free Ca2+ concentration that induces exocytosis of insulin-containing granules (Henguin et al., 2009).
Insulin resistance describes the state where insulin produces an inadequate biological effect, causing decreased insulin-induced muscle and adipose glucose uptake and increased hepatic glucose production. Subjects suffering from type 2 diabetes have some depletion of β-cells and exhibit increased β-cell apoptosis (Butler et al., 2002). However, the extent of β-cell depletion is controversial and trials of bariatric surgery and intense caloric restriction demonstrate that recovery of insulin production is possible in type II diabetics.
Sulfonylurea drugs have been a popular strategy for the development of novel treatments for type 2 diabetes over the last 60 years. This class of drug works by binding directly to the KATP channel, and thus inducing the secretion of insulin from the β-cells.
Endoplasmic Reticulum (ER) Stress
The ER is a major protein-folding compartment in a eukaryotic cell and is second only to the cytosol, and is the site of synthesis for all secretory and cell surface proteins. Protein folding in the ER is more complex than protein folding in the cytosol because proteins are post-translationally modified. Folding in the ER must couple protein-synthesis pathways operating outside of the compartment with ER-assisted folding (ERAF) pathways in the lumen. Expression of a mutant version of a protein, or even some-wild-type proteins, viral infection, energy or nutrient depletion, extreme environmental conditions, or stimuli that elicit excessive calcium release from the ER lumen compromise protein-folding reactions in the ER, causing unfolded protein to accumulate and initiate a cascade of signals that are transmitted to the cytoplasm and nucleus. When the protein-folding demand on the ER exceeds the folding capacity of the ER a condition termed "ER stress" results (Malhotra et al., 2007). ER stress can also result from other conditions, namely when a protein that is translated in the cytosol is misfolded and induces the recruitment of the folding machinery, leading to a deficit of folding assistance in the ER.
The overproduction of secretory proteins has been demonstrated to generate ER stress and it is well known that pancreatic islet β-cells sustain a high rate of insulin production and secretion. ER stress occurs when protein-misfolding increases beyond threshold levels, releasing a suite of signaling and transcriptional events known collectively as the unfolded protein response (UPR). The ultimate goal of the UPR is to restore ER protein biosynthesis, but paradoxically one initial step is a suppression of translation of the secretory proteins, such as insulin in the β-cell, to relieve ER load. Accordingly, the physical response mechanism, whilst protecting the secretory cell, can have adverse physiological effects. For example, in β-cells this would be a reduction in insulin production and, hence, hyperglycemia. Both β-cell ER stress and insulin misfolding have been reported in both type 2 diabetes and autoimmune type 1 diabetes.
β-cells are long-lived cells that require a highly developed ER in order to produce extremely large amounts of insulin over a long period of time. This insulin generation requires a complex series of molecular biosynthetic events that are initiated in the ER. Pre-pro-insulin, the precursor of mature insulin, is cotranslationally translocated in the ER lumen, where the signal sequence is cleaved and proinsulin is generated. Machinery enzymes in the ER catalyze the formation of three disulfide bonds, to help form its native shape, before being trafficked to the Golgi apparatus and secretory granules. Finally, in the downstream Golgi it is further processed by endoproteases and the C-peptide is removed, generating the final product, mature insulin.
Potential contributors to β-cell ER stress in type 2 diabetes include increased insulin biosynthesis, lipotoxicity due to saturated long chain free fatty acids (FFA) such as palmitate (a side effect of obesity), increased reactive oxygen species (ROS) production in the ER due to increased disulfide bond formation and by mitochondria due to high glucose, and progressive accumulation of amyloid deposits (Cnop et al., 2012, Cunha et al., 2008).
The precise molecular mechanisms governing how insulin resistance interrelates to β-cell dysfunction are currently not well understood, with many obese individuals being highly insulin resistant without developing β-cell dysfunction and diabetes. However, insulin resistance adds to the demand for increased insulin biosynthesis in β-cells. Furthermore, the inappropriate secretion of the proinsulin precursor by β-cells, which increases as diabetes progresses, is thought to contribute to increased insulin resistance. Loss of cyclicity of insulin release from the pancreas also occurs in diabetes and contributes to increasing insulin resistance. Oxidative stress, ER stress, amyloid deposition in the pancreas, as well as both lipotoxicity and glucotoxicity are believed to play a role in progressive β-cell dysfunction, and are all caused by over-nutrition.
IL-22 Treatment
Huang et al. (U.S. 2010/0015086) have shown that injection of recombinant IL-22 (rIL-22) can reduce total serum glucose, triglyceride and insulin levels as well as body weight in obese mice. They have also shown that systemic administration of rIL-22 can improve glucose tolerance and insulin sensitivity in normal mice. Based on these observations, Huang et al. propose that rIL-22 would be useful for treating metabolic disorders including obesity, diabetes, hyperlipidemia, hyperglycemia and hyperinsulinemia. However, Huang et al. do not disclose any mechanism of action to explain how rIL-22 achieves these effects.
The present inventors observe, however, that no clinical trials have been published that support the use of systemic administration of rIL-22 for treating metabolic disorders in humans since publication of Huang et al. and that this may be due to possible off-target effects of rIL-22. For example, chronic high concentrations of IL-22, and low concentrations of the counteracting IL-22 binding protein (Dumoutier et al., 2001), have been shown to contribute to hyperplasia and tumor development in the intestine in animal models (Huber et al., 2012; Kirchberger et al., 2013; Yu et al., 2013; Jiang et al., 2013). IL-22 has also been reported to induce hepatocyte proliferation and overexpression of IL-22 in the liver has been shown to increase the rate of carcinogen-induced liver cancers (Park et al., 2011). It has also been reported that IL-22 is associated with human hepatocarcinomas, and that carcinogen-induced liver cancers are reduced in IL-22 knockout mice (Jiang et al., 2011). IL-22-producing CD8 T cells have been found associated with transplant-associated skin cancers and possibly contribute to squamous cell carcinoma growth or development in this setting (Zhang et al., 2013). As shown herein, the present inventors have also discovered that systemic administration of rIL-22 has the potential to exacerbate viral infections in humans.

Modulation of cellular stress using a B-cell oxidative and/or endoplasmic reticulum stress inhibitor and a targeting agent


A method of manufacturing a semiconductor structure includes receiving a substrate and an interlayer dielectric (ILD) over the substrate; bonding the substrate and the ILD over a carrier substrate; forming a recessed portion extended through the substrate and the ILD; disposing a conductive material into the recessed portion; and removing the carrier substrate, wherein the conductive material is in contact with the ILD and is separated from the substrate.

Electronic equipment using semiconductor devices are essential for many modern applications. Semiconductor image sensors are commonly involved in electronic equipment for sensing light. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) are widely used in various applications, such as digital camera and mobile phone cameras. The CMOS image sensor typically includes an array of picture elements (pixels). Each pixel includes a photo-diode, a transistor or a capacitor. An electrical energy is induced in the photo-diode upon exposure to the light. Each pixel generates electrons proportional to an amount of light falling on the pixel. The electrons are converted into a voltage signal in the pixel and further transformed into digital signal.
The CMOS image sensors are classified as front side illuminated (FSI) image sensors and back side illuminated (BSI) image sensors, depending on the light path difference. The BSI image sensors are gaining in popularity. The pixels in the BSI image sensor generate electrical signals in response to incident light. Magnitudes of the electrical signals depend on the intensity of the incident light received by the respective pixels. The light is incident on a back side of a substrate of the BSI image sensor and hits the photo-diode directly, without obstruction from dielectric layers and interconnect layers formed on a front side of the substrate. Such a direct incidence makes the BSI image sensor more sensitive to the light.
However, as technologies evolve, the image sensor is becoming increasingly smaller in size while having greater functionality and greater amounts of integrated circuitry. The manufacturing of the BSI image sensor involves many complicated steps and operations. Since more different components with different materials are involved, complexity of the manufacturing and integration operations of the BSI image sensor is increased. An increase in a complexity of manufacturing of the BSI image sensor may cause deficiencies such as poor quantum efficiency (QE), strip line defect, dark current, low full well capacity (FWC), high yield loss etc. The BSI image sensor is produced in an undesired configuration, which would further exacerbate materials wastage and increase the manufacturing cost.
Therefore, there is a continuous need to improve a structure and a manufacturing method for of the BSI image sensor device in order to improve the performance of the BSI image sensor device as well as reduce cost and time on processing the BSI image sensor.

Semiconductor structure and manufacturing method thereof

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.