For the purpose of recovering sodium hyroxide and zinc from waste water from low cyanide zinc plating baths, an electrolytic technique was investigated using cation exchange membrane as diaphragm. Granulated graphite anode used exhibited exellent durability and high efficiency for decomposing cyanide. Continuous operation tests showed that the recovering rates of sodium and zinc ions were 10.2mg/min and 1.4mg/min at diaphragm c. d. of 2A/dm2 (the area of the diaphragm on one side was 0.44dm2). Zinc was found to accumulate in the graphite anode as zinc hydroxide and zincate. The amount of zinc recovered was almost 90%.
Low Cyanide Zinc PlatingBaths by Electrolytic Methode.Waste water from low cyanide zinc plating baths was electrolyzed in an industrial scale to recover alkali and zinc and to decompose cyanide.Granulated graphite anodes and cation exchange membranes as diaphragms were used in constructing our electrolytic cell. The rate of recovery of plating solution was about 4.8l/h at a total current of 300A (diaphragm c.d.: 2A/dm2). The percentage for the recovery of alkali and zinc was found to be 104 and 92.7%, respectively, and 85.7% of cyanide was decomposed. Almost all zinc was accumulated on the graphite anode as zinc hydroxide and sodium zincate.Ind. Inst. for Precision Machinery, Nagano pref.(9959, Okaya-shi, Nagano 394)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.