A considerable amount of gold is recovered from cyanide-containing solutions, both in primary and secondary gold-producing industries. In the jewelry industry, the gold-containing waste cyanide is generated when the final shiny finish on jewelry is reached by reacting it with a solution mixture of sodium cyanide and hydrogen peroxide (commonly called bombing) or by electroplating the gold from cyanide solution. In the electronics industry, a large volume of waste gold cyanide solution is generated after plating the electronic parts components with gold. In the mining industry, the gold is dissolved in cyanide solution and then recovered from it by various processes. In primary aluminum production, cyanide is produced as a by-product during electrolysis of molten salt. In the secondary precious metals industry, considerable amounts of cyanide waste solution are generated when the gold from plated parts is dissolved from the surface (commonly called stripping) and then gold is recovered. Over the years, all these different industries have developed various processes to solve their problems. Some of the processes are chlorination, hydrolysis, ozonation, etc. This paper is a review of cyanide destruction with special emphasis on gold recovery from waste solutions

Author: Dr. Rajesh Mishra