METHOD OF EXTRACTING SILVER FROM SPENT PHOTOGRAPHIC SOLUTIONS, WASHING AND SEWAGE WATERS Russian patent published in 2001 - IPC

FIELD: hydrometallurgy of noble metals; applicable in extraction of silver from spent solutions and washing waters formed in processing of light-sensitive silver-containing materials including colored ones, and from other silver-containing solutions. SUBSTANCE: method includes sorption of silver from spent photographic solutions and sewage waters, separation of sorbent saturated with silver from solution, drying, firing of saturated sorbent and smelting of metal silver from concentrate. Sorbent is used in the form of bis-(dimethylthiocarbamyl) disulfide. Sorption of silver is effected under static conditions with consumption of 1.5-1.6 g of sorbent per gram of silver contained in solution. Sorption of silver under dynamic conditions is carried out with use of the same sorbent applied to porous carrier with developed surface, for instance, activated carbon with particles sizing within 0.1-1.5 mm. Use of bis-(dimethylthiocarbamyl) disulfide sorbent makes it possible to extract silver in wide range of its concentrations and pH of medium of fixing solutions of black-white and colored photographic films and from other washing and sewage waters. Claimed method is relatively simple and applicable in production in wide range. EFFECT: higher efficiency of method due to high sorption capacity of sorbent and reduced time of sorption process. 3 cl, 8 dwg