Precious metals can be recovered from three main sources: solutions and electrochemical wastes; smeltable materials and slags; printed circuits and electronic scrap . Owing to their value rigorous recovery procedures are usually adopted in factories which manipulate, machine and fabricate these materials. Floor sweepings, water from hand washing and polishing cloths are all potential sources of secondary precious metals as well as the richer sources which include anode slimes from electrolytic plants, old medals and coins, brazing alloys and solders, jewellery and dental wastes and platinum catalytic reagents which are used in the chemical and petrochemical industry. In general, solid wastes follow a pyrometallurgical recovery route and liquids a hydrometrallurgical or electrometallurgical route with a final electrorefining process usually being adopted. However, intermediate products from one route may be passed into the other . There are three main process losses: slag, liquid or ‘trade waste’, and gaseous emissions which, because of their value and legislative requirements, must be kept to a minimum.
Precious metals can be recovered from three main sources: solutions and electrochemical wastes; smeltable materials and slags; printed circuits and electronic scrap . Owing to their value rigorous recovery procedures are usually adopted in factories which manipulate, machine and fabricate these materials. Floor sweepings, water from hand washing and polishing cloths are all potential sources of secondary precious metals as well as the richer sources which include anode slimes from electrolytic plants, old medals and coins, brazing alloys and solders, jewellery and dental wastes and platinum catalytic reagents which are used in the chemical and petrochemical industry. In general, solid wastes follow a pyrometallurgical recovery route and liquids a hydrometrallurgical or electrometallurgical route with a final electrorefining process usually being adopted. However, intermediate products from one route may be passed into the other . There are three main process losses: slag, liquid or ‘trade waste’, and gaseous emissions which, because of their value and legislative requirements, must be kept to a minimum.
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