银电解废液旋流电积试验

Experimental study on cyclonic electrowinning of silver electrolysis waste liquor

本文采用旋流电积试验设备对银电解废液进行电积试验,研究了废液A(银离子浓度为15.42 g/L)和废液B(银离子浓度为47.42 g/L)2种典型的银离子浓度废液的电积情况,结果表明:废液A以500 A/m^(2)电积40 min,250 A/m^(2)电积20 min,可产出符合IC-Ag99.99标准化学品质的银粉,合格银粉的直收率达到79.2%;废液B以750 A/m^(2)电积90 min,500 A/m^(2)电积40 min,250 A/m^(2)电积40 min,可产出符合IC-Ag99.99标准化学品质的银粉,合格银粉的直收率达到72.7%,银电解废液电积过程中杂质铜、钯主要随着银的逐渐贫化后开始大量析出;随着电积过程铜、钯等杂质不断析出,实现了电解液脱杂的目的,电积后液可返回银电解系统继续使用,同步实现了银电解过程的废水零外排,克服了在银电解废液中硝酸根处理难度大的问题。

The electrowinning experiment of silver electrolytic waste liquor was carried out by using cyclone electrowinning equipment,the electrowinning conditions of two kinds of typical silver ion concentration waste liquid A(silver ion concentration 15.42 g/L)and B(silver ion concentration 47.42 g/L)were studied.The results showed that the silver powder of IC⁃Ag 99.99 standard could be produced by using 500 A/m^(2) for 40 min and 250 A/m^(2) for 20 min in waste liquid A,the direct yield of qualified silver powder reached 79.2%;the silver powder of IC⁃Ag 99.99 standard could be produced by using 750 A/m^(2) for 90 min,500 A/m^(2) for 40 min and 250 A/m^(2) for 40 min in waste liquid B,the direct yield of qualified silver powder reached 72.7%,the impurity copper and palladium in the process of electrowinning of silver electrolytic waste liquor began to precipitate largely with the decrease of silver;with the electrowinning process copper,palladium and other silver electrolyte needed to be purified impurities continue to produce,the aim of impurity removal of electrolyte was realized,the electrowinning liquid could return to the silver electrolysis system to continue to use,the zero discharge of waste liquid in silver electrolysis process was realized simultaneously,the method overcame the problem that nitrate was difficult to be treated in silver electrolysis waste liquor.