METHOD FOR REFINING SILVER AND METHOD FOR RECOVERING SILVER FROM PHOTOGRAPHIC MATERIAL, PHOTOGRAPHIC PROCESSING SOLUTION OR PHOTOGRAPHIC EMULSION

摘要

PURPOSE:To efficiently recover metal silver from a compsn. contg. silver or silver compd. and a relatively large amt. of impurities such as specified metals by heating the compsn. at a specified temp. in the presence of an inorg. oxidizing agent when silver is refined from the compsn. CONSTITUTION:A compsn. contg. silver or silver compd. and further contg. Zn, Ti, Sn, Al, In, Mg, Ba, Si, Mo, Sb, Nb, Ta, Bi, Pd, Cd and Pb in the form of metals or compds. as impurities by =0.1mol% of the amt. of silver is heated to =400 deg.C in the presence of an inorg. oxidizing agent.. When silver is recovered from a photographic material, a photographic processing soln. or a photographic emulsion, sludge rich in silver or silver compd. is collected and smelted at =400 deg.C in the presence of an inorg. oxidizing agent such as an alkali metallic nitrate. By the action of the inorg. oxidizing agent, silver becomes the state of metal and each of other metals as impurities becomes the state of oxide, therefore silver can easily be separated from the other metals.