Hydrometallurgical process for the recovery of silver as silver halide or silver pseudohalide from waste photographic paper and film and other sensitized materials

摘要

The invention provides a process for the recovery of transition and post-transition metals the halides and pseudohalides of which are hyperlinearly soluble in excess halide or pseudohalide, and especially of silver as halide or pseudohalide from waste photographic paper, photographic film, and other sensitized materials. The process comprises washing the material, removing wash, bringing the silver present to a form solubilizable in concentrated halide or pseudohalide solution, by oxidation if necessary, dissolving the silver salt or salts by means of a concentrated reagent solution of the halide or pseudohalide of an alkali or alkaline-earth metal, or ammonium, separating said complex solution from solid matter, washing the solid in turn with a dilute solution of the halide or pseudohalide and then with water, treating said separated complex solution with said dilute halide or pseudohalide wash and water- wash combined to form a precipitate and separating the precipitate of said silver halide or pseudohalide, reconcentrating dilute reagent, separating unwanted, accumulated salts from reagent and purifying silver salt.