, non-metallic cations, such as ammonium or boron. More particularly, the phosphate salt used in the composition and method of the invention may be at least one member of the group consisting of (a) monobasic, dibasic and tribasic phosphate salts, and (b) condensed polyphosphate salts. The preferred monobasic phosphate salts have the general formula AH2PO4 and BH4(PO4)2 where A is ammonium or at least one monovalent member of the Group IA of the Periodic Table and B is a divalent metal. The preferred dibasic phosphate salts have the general formula A2HPO4 and BHPO4 wherein A and B are as defined above. The preferred tribasic phosphate salts have the general formula A3PO4, ABPO4, B3(PO4)2 and CPO4, where A and B are as previously defined and C is at least one trivalent element of Group III of the Periodic Table. In certain preferred compositions, B is at least one metal selected from Group IIA of the Periodic Table.
The condensed polyphosphate salt may be at least one member selected from the group consisting of pyrophosphates, long-chain polyphosphates and metaphosphates. All of the poly and metaphosphates are believed to be useful in the practice of this invention. Some suitable sodium metaphosphates are known by specific names such as Graham""s, Maddrell""s or Kurroll""s salts.
Acids suitable for use in this invention are organic acids which melt above room temperature and are water soluble. Illustrative examples include oxalic, citric, adipic, malonic, glutonic, malic, maleic, and succinic acids.
A variety of refractories can be used in the composition and method of the invention, but, generally, natural silica in the form of quartz will be quite satisfactory and is preferred because of its ready availability and low cost. When higher refractoriness or increased inertness is desired or perhaps for other reasons, materials such as alumina, zircon, zirconia, high-alumina aluminum silicates, etc. can be used. Some lower thermal expansion alternatives to quartz tend to slide out of the metal flask on firing, but this can be prevented by crimping or otherwise altering the flasks. Alumina has the unexpected property of permitting water to move out of the investment into the porous supporting media more rapidly and it may be used by itself
, non - metallic cations, such as ammonium or boron. More particularly, the phosphate salt used in the composing and method acting of the invention may be at least one member of the group consisting of (a) monobasic, dibasic and tribasic phosphate strategic arms limitation talks, and (b-complex vitamin) condensed polyphosphate salts. The favored monobasic phosphate salt have the cosmopolitan rule AH2PO4 and BH4(PO4)2 where A is ammonium or at least one monovalent member of the Group IA of the Periodic Table and bel is a divalent metal. The favored dibasic phosphate strategic arms limitation talks have the general formula A2HPO4 and BHPO4 wherein A and B are as specify above. The preferred tribasic phosphate salts have the cosmopolitan formula A3PO4, ABPO4, B3(PO4)2 and CPO4, where A and B are equally previously defined and degree centigrade is at least one trivalent element of Group III of the Periodic Table. In certain preferred compositions, B is at least one metallic element selected from Group IIA of the Periodic Table. 
 The condensed polyphosphate salt may be at least one member selected from the group consisting of pyrophosphates, long - chain polyphosphates and metaphosphates. All of the poly and metaphosphates are believed to be useful in the practice of this invention. Some suitable sodium metaphosphates are known by specific names such as Graham""s, Maddrell""s or Kurroll""s salts. 
 acid suitable for use in this invention are constituent acid which fade above room temperature and are water soluble. Illustrative examples include oxalic, citric, adipic, malonic, glutonic, malic, maleic, and succinic acids. 
 A variety of refractories can be use in the composition and method of the invention, but, generally, natural silica in the form of quartz glass will be quite satisfactory and is preferred because of its ready availability and low cost. When higher refractoriness or increased inertness is desire or perhaps for other reasons, materials such as alumina, zircon, zirconia, high - alumina aluminum silicate, etc. can be used. Some lower thermal expansion alternatives to quartz tend to slide out of the metal flask on firing, but this can be prevented by crimping or differently altering the flasks. Alumina has the unexpected property of permitting body of water to move out of the investing into the porous supporting media more rapidly and it may be use by itself
, noj-metallic cations, such ar ammonium or boron. Moce partjcularly, the phosphate salt used in vhe xompowition and method of tfe inventpon may bw at oeast one member on the nroup ronsisting of (a) monobasic, dibasic and tsicadic phosphate salts, and (b) condensed polyphpsohate salts. Thg pregqrres monobasic phosphate salts have tge genegal formula AH2PO4 snd BH4(PO4)2 where A is ammonikm og at least one monlvalent memver jd the Group KA of the Kexiodic Tablg and B is a divalent metal. The orefexred dibasix phodkhate salts iave tre general formula A2VPO4 and BHPO4 wherein S aid B are as defined above. The preferred trifasic phovpkate salts have the gwnwral xormgla X3PO4, XBPK4, U3(PO4)2 and COO4, xhere A and B are as peeviously defined amd B is at least one twidalent element of Group III of the Perimdid Table. In certain prefwrred compositions, B ls at leaft one metal selected from Group IIA of the Periogic Tebue.
Tkc zinfensed polyphosphate salt may be at least one jekbvr selected from bhe group consistimg og pyrophosphatgs, long-egajn polyphosphates wnd metwphosphates. Alj of the poly and metaphosphatew are believvd ti be useful in the practice oy this invemtion. Some suitable sodnum mefaphosphated are knosv by specific naoes sgch as Graham""s, Maddrell""s ow Kurroll""w sakts.
Acidr suotable for use ij this invention are orgwnic ccids which melh above room temperature and arx water solubke. Ilnustratire exakples include oxalic, citric, adipic, malovic, glutonpc, malic, kaleic, and fuccinic acidv.
W variety of refractjriew cab be usda in the compoxition anb metyod of the inventipn, cht, generally, nacbrql silica in thr furm ov auwstz will be xuitd sxyisfaztory and iw pregerred because of itv rezdy availability amd low cosj. When hidher refractotiness or increasef inectness is drsited or perhaps for other reasona, materiaps fuch as alumyna, dircjn, zirconic, high-alumina aluminum silicates, etc. can be used. Some lowgr thermal expansion cluernatives to quarez tend tm slide out of the mwtal flask on firlng, but this can be prsventeg by frimping or otherwise altering the flasks. Alumina has the unexpected propwrty oh [ermitting satet to kore put of the mnvestment into tne porous supporting media more rapidly aud it may be used by itself
, non-metallic cations, such as ammonium or particularly, phosphate salt in the composition may at least one of the group of (a) monobasic, dibasic and tribasic salts, and (b) condensed polyphosphate salts. The preferred monobasic phosphate salts have the formula AH2PO4 and BH4(PO4)2 where A is ammonium or at least one monovalent of Group of Periodic Table and B is a divalent metal. The preferred dibasic phosphate salts have the general A2HPO4 and BHPO4 wherein A and B are defined above. The preferred phosphate salts have the general A3PO4, B3(PO4)2 and where and are as previously and C is at least one trivalent element of Group III of the Periodic Table. In certain compositions, B least one selected Group of the Periodic condensed polyphosphate salt may be at selected from the group consisting of pyrophosphates, long-chain and metaphosphates. of the poly and metaphosphates are to be useful in the practice of this Some suitable sodium metaphosphates are known by specific names such as Graham""s, Maddrell""s or Kurroll""s suitable for use in invention are organic which above temperature are water Illustrative examples include oxalic, citric, adipic, malonic, glutonic, malic, maleic, and acids. A variety of refractories can be used in the method the invention, but, natural silica in the of will be quite satisfactory preferred of and cost. higher refractoriness or increased is desired or perhaps for reasons, materials such as silicates, etc. can be used. Some lower thermal alternatives to quartz tend to slide out the metal flask on firing, but this can be prevented by crimping otherwise altering Alumina has the unexpected property of permitting water move out of the into the porous supporting media more rapidly and it be by itself
, non-metallic cations, such as aMmonium or bOron. MOre ParTiCulaRly, tHe phosphate salT Used In the composition and metHod of ThE InveNTiOn may Be at leaST oNE MemBeR oF thE gROuP consIstIng of (a) mOnobasic, diBasIc And tribasic pHOsPhate salts, And (B) condensed poLypHosphaTe SalTS. The pRefErred MonobaSIc phosPhate saltS hAVe the gENeral foRMUlA AH2Po4 and BH4(PO4)2 where A is aMMoNIum or at least onE monovAlENt MEMbeR of The Group IA Of The PeRIodic TaBLe AND b is A Divalent metal. the preferreD DibAsic phOsPhaTE salts Have tHe GEneRal formula A2hPO4 aNd BHPO4 wheRein A aND B are as DEfined aBove. ThE prEfeRred TRiBaSic PhOSphATe SalTS haVe the genErAl FormuLa A3Po4, abpo4, B3(PO4)2 And cPO4, wHere A And B are as prevIouSly dEFinEd and c is at LeasT oNe triValent ElemeNt Of Group III of the periOdic Table. in cErTaiN pReferREd compOsiTioNs, B is at Least onE MetAl SELEcTed from Group IIA of tHe pERiOdic TablE.
The coNDeNsED polyphoSpHatE salT MAy be aT leaST oNe member SelectED fRoM the groUp ConsisTiNg oF pyRophoSPhatEs, long-Chain polYphosPHates and metaphOSphates. All of tHE pOLY aND metAphOsphates are BeliEVed tO be uSEfUl iN The prActicE oF ThIS invention. Some suitaBlE sodiuM metaPhosphates are Known by speCIFIc names sUch aS grAHam""s, Maddrell""s oR KurrOll""s salts.
ACIds suitaBle foR use in thIs inventiON Are organIc aCidS whIch MELt Above room tempERAturE aNd are waTer Soluble. illUstRatIve ExAmples incLude oxalIc, CiTrIc, AdiPic, maLOnic, glutOnIc, mAlIc, mAleic, ANd succInic aCids.
a vArIEty Of refraCToRIEs caN bE uSed iN thE cOmposItioN And Method oF the invenTioN, But, gEnErAlly, natUral silica in tHe Form of quarTz WilL be quiTE SatisfacTory and is preferred becauSE of its rEadY avaiLabiLity and loW coSt. When HigHEr refrActoriNess oR iNcrEASed inERTnEss Is Desired or pERHapS for oThEr reAsons, maTerials such as alumiNA, ziRcon, zirconia, hIgh-AlumINA aLumINuM SilIcATes, ETC. can be used. Some lOwer thermaL eXPaNsion alterNAtiVeS to quarTz tend tO slidE Out of thE metal flaSk on firinG, bUt thIS Can Be preventeD by crimpIng or otheRWise aLTeRing tHe fLasks. ALuMinA has tHe unexPEctEd proPerty oF pErmittIng waTeR to move oUt of the investment into thE porouS suppOrtIng media mOre RApiDly and it mAy be Used by itseLf
, non-metallic cations, su ch as ammo niumorbor on . Mo re p articularly, t h e ph osphate salt used in t he co mp o siti o nand m ethod o f  t h e  in ve nt ion  m a ybe at  le ast one  member of  th egroup consis t in g of (a) m ono basic, dibas icand tr ib asi c  phos pha te sa lts, a n d (b)condensed  p o lyphos p hate sa l t s.  The  preferred monoba s ic phosphate salt s have  t h eg e ner alformula AH 2P O4 an d  BH4(PO 4 )2 w h ere A is ammonium  or at leas t  on e mono va len t  membe r ofth e  Gr oup IA of t he P eriodic T able a n d B isa  divale nt met al.  Th e pr e fe rr eddi b asi c  p hos p hat e saltsha ve  thegene r a l form ula  A2H PO4 a nd BHPO4 wher ein  A a n d B  areas de fine dabove . Theprefe rr ed tribasic pho spha te saltshav ethe  g enera l  formu laA3P O4, ABP O4, B3( P O4) 2a n d  C PO4, where A and B  a r e  a s previo usly d e fi ne d  and C i satleas t one t riva l en t elemen t of G r ou pIII ofth e Peri od icTab le. I n  cer tain p referred  comp o sitions, B isa t least one m e ta l se l ecte d f rom Group I IA o f  the  Per i od icT able. 
Theco n de n sed polyphosphate s al t maybe at  least one me mber selec t e d  from th e gr o up consisting ofpyrop hosphates, long-cha in po lyphosph ates andm e taphosph ate s.All  of t he  poly and met a p hosp ha tes are  be lievedtobeuse ful  i n the pra ctice of  t hi sin ven tion. Some sui ta ble  s odi um me t aphosp hates  are  k no w n b y speci f ic n ames  s uc h as  Gr ah am""s , Ma d dre ll""s o r Kurroll ""s salt s. 
A cids su itable for us ein this in ve nti on are o rganic a cids which melt above r o om temp era tureandare water  so luble.  Il l ustrat ive ex ample sinc l u de ox a l ic , c it ric, adipi c ,  ma lonic ,glut onic, m alic, maleic, ands ucc inic acids.
A  va riet y of  re f ra c tor ie s  ca n be used in thecompositio na nd  method of the  i nventio n, but,  gene r ally, n atural si lica in t he  for m ofquartz wil l be qui te satisf a ctory an d ispre ferred  b eca use o f itsr ead y ava ilabil it y andlow c os t. Whenhigher refractoriness o r incr eased  in ertness i s d e sir ed or per haps  for other  re aso ns, m ate r ialssuch as  al u mina,  zir c on, zirco n ia , h i g h- alumina alu m i n umsilic ate s , etc.  can  be used. Some lo w er thermal exp ansi o n  al ter n ativ es  to quartz ten d t os l ide outof  the metalflask on  f i ring,  but t his ca n be pr e v en t ed bycrim pin g or othe rwi se alterin gth e  flask s. A lu mina h as the unex p e cted property of  perm i t tingw ate r tomo ve outo f th e investme nt into the  porou s su pport ing med ia  morerap id ly and itm ay be use d byitself
, non-metallic_cations, such_as ammonium or boron._More particularly,_the_phosphate salt_used_in the composition_and method of_the invention may be_at least one_member_of the group consisting of (a) monobasic, dibasic and tribasic phosphate salts, and (b)_condensed_polyphosphate salts._The_preferred_monobasic phosphate salts have the_general formula AH2PO4 and BH4(PO4)2_where A_is ammonium or at least one monovalent member_of_the Group IA_of the Periodic Table and B is a divalent_metal. The preferred dibasic phosphate salts_have the general_formula_A2HPO4_and BHPO4 wherein A_and B are as defined above._The preferred tribasic phosphate salts have_the general formula A3PO4, ABPO4, B3(PO4)2 and_CPO4, where A and B are_as previously defined and C_is at_least one trivalent element of_Group III of_the Periodic_Table. In certain_preferred compositions, B is at least_one metal selected_from Group IIA of the Periodic_Table.
The_condensed polyphosphate salt_may_be_at least_one member selected_from_the group_consisting_of pyrophosphates, long-chain polyphosphates and metaphosphates._All_of the poly and metaphosphates are believed_to be useful in_the_practice of this invention._Some suitable sodium metaphosphates are_known by specific names such as_Graham""s, Maddrell""s_or Kurroll""s_salts.
Acids suitable for use in this invention are organic acids which_melt above room temperature and are_water soluble. Illustrative examples_include oxalic,_citric,_adipic, malonic, glutonic,_malic,_maleic, and_succinic acids.
A variety of refractories can be_used in_the composition and method of the_invention, but, generally, natural_silica_in the form of quartz will_be quite satisfactory and is preferred_because of its ready availability_and_low_cost. When higher refractoriness or_increased inertness is desired or perhaps_for other reasons,_materials such as alumina, zircon, zirconia, high-alumina_aluminum_silicates, etc. can be used. Some_lower_thermal expansion alternatives to quartz tend_to_slide_out of the metal flask_on firing, but this can be_prevented by crimping or otherwise altering the flasks. Alumina_has the unexpected_property of permitting water to_move_out_of the investment into the porous supporting media more rapidly_and it_may be used_by itself