recycling industry is challenged by the dispersed location of recycling centers, and the cost associated with transporting recycled metals from remote locations. Variations in the market price of recycled aluminum also affect the profitability of recycling sites. Aluminum Extracting aluminum from airplanes is difficult because aircraft compounds typically contain relatively high amounts of mixed metal alloys and new aircraft generally need aluminum with lower levels of impurities. Additionally, the variety of aluminum alloys that have good performance and can be produced directly from recycled aluminum is limited. Another limitation for recycling aluminum for aircraft is a lack of automation in the recycling process. Safely dealing with hazardous materials when recycling aircraft poses further operational challenges. Hazardous materials are more likely to be found in old aircraft which may contain substances such as asbestos, hexavalent chromium (found in paint primer) and halon 1301 (found in fire extinguishers). The presence of lithium with aluminum, found in some aircraft alloys, is dangerous as it can explode when the scrap aluminum is remelted. Composite materials The primary challenges for recycling composite materials are high cost, weaknesses in the physical properties of recycled composites, and the lack of demand for recycled composites. Carbon fiber is a composite material that is currently not widely recycled. With the current processes in place, it is difficult to sort through composite materials before recycling can occur. This is especially the case with metal that is intertwined in composite pieces. The carbon fiber that is recycled is generally not turned into subsequent carbon fiber products, instead being used for applications such as cheap filler material. See also Aircraft boneyard Airliner Aluminium recycling References External links Recycling industry