公开(公告)号：US4445935A

公开(公告)日：1984-05-01

申请号：US449312

申请日：1982-12-13

申请人： Franz A. Posey ,  Aloysius A. Palko

发明人： Franz A. Posey ,  Aloysius A. Palko

IPC分类号： G03C5/38 ,  C02F1/62 ,  C22B7/00 ,  C22B11/00 ,  G03C11/24 ,  C22B11/06

CPC分类号： C22B7/008 ,  C22B11/04 ,  Y02P10/234

摘要： The method of the present invention is directed to the recovery of silver from spent photographic fixer solutions and for providing an effluent essentially silver-free that is suitable for discharge into commercial sewage systems. The present method involves the steps of introducing the spent photographic fixer solution into an alkaline hypochlorite solution. The oxidizing conditions of the alkaline hypochlorite solution are maintained during the addition of the fixer solution so that the silver ion complexing agents of thiosulfate and sulfite ions are effectively destroyed. Hydrazine monohydrate is then added to the oxidizing solution to form a reducing solution to effect the formation of a precipitate of silver which can be readily removed by filtration or decanting. Experimental tests indicate that greater than 99.99% of the original silver in the spent photographic fixer can be efficiently removed by practicing the present method. Also, the chemical and biological oxygen demand of the remaining effluent is significantly reduced so as to permit the discharge thereof into sewage systems at levels in compliance with federal and state environmental standards.

摘要翻译： 本发明的方法涉及从废照相定影剂溶液中回收银并提供基本上不含银的流出物，其适于排放到商业污水系统中。 本方法包括将用过的照相定影剂溶液引入碱性次氯酸盐溶液的步骤。 碱性次氯酸盐溶液的氧化条件在添加定影剂溶液期间保持，使得硫代硫酸盐和亚硫酸根离子的银离子络合剂被有效地破坏。 然后将一水合肼加入到氧化溶液中以形成还原溶液以形成银沉淀物，其可以通过过滤或倾析而容易地除去。 实验测试表明，通过实施本方法可以有效地除去废照相定影剂中原始银的99.99％以上。 此外，剩余废水的化学和生物需氧量显着降低，以便允许以符合联邦和州环境标准的水平排放到污水系统中。