Chemical and Biological Cyanide Destruction and Selenium Removal from Precious Metals Tailings Pond Water.
Lien-RH; Dinsdale-BE; Gardner-KR; Altringer-PB
Paper in Epd Congress '90 Minerals Metals & Materials Society 1990 :323-339
The U.S. Bureau of Mines is investigating chemical and biological decontamination of complex wastewaters such as tailings pond water containing 280 ppm cn and 5 ppm se as well as significant concentrations of arsenic, copper, iron, silver, and zinc. The most effective chemical procedure involves cyanide oxidation using hydrogen peroxide or sodium hypochlorite followed by selenium reduction using ferrous hydroxide. The effluent contains less than or equal to 1 ppm cn and 20 ppb se; concentrations of other major contaminants meet Environmental Protection Agency drinking water standards. Preliminary research indicates that biological cyanide oxidation is possible even in highly alkaline solutions (ph 10.5) Containing high cyanide concentrations; indigenous bacteria destroyed 85 pct of the cyanide. Exploratory research shows that other bacteria removed up to 79 pct of the selenium from chemically oxidized, low-cyanide water. These promising results may lead to a final processing scheme that involves a combination of chemical and biological techniques.
Paper in Epd Congress '90. Minerals, Metals & Materials Society, 1990, PP. 323-339