抄録
Heavy electrodeposition of silver from highly concentrated cyanide baths was studied in terms of bath composition, cathodic polarization curves and the range of appropriate current densities. The structure of silver cyanide complex in the bath was also studied. It was found that highly concentrated potassium hydroxide effected a remarkable improvement in the characteristics of cyanide baths for heavy electrodeposition of silver. The range of appropriate potassium carbonate concentration was increased by the addition of potassium hydroxide into the baths. Cathodic polarization was increased by increases in the concentration of potassium carbonate, but was changed little by the addition of potassium hydroxide. The structure of silver cyanide complex was estimated to be Ag(CN)32-. The following conditions for heavy electrodeposition of silver in cyanide solutions can be recommended: AgCN: 120-134g/L, KCN: 176-195g/L, KOH: 20-40g/L, K2CO3: 140-170g/L and current densities of 1-3A/dm2.
