method for removing cyanide from an aqueous stream, process for treating a cyanide-containing stream, process for treating an aqueous stream containing valuable metals and integrated process for leaching an aqueous stream containing valuable metals.

摘要

This invention relates to a method of removing cyanide in the form of free cyanide (cyanide ions i.e. CN) and weak acid dissociable cyanide (WAD) from an aqueous stream. WAD is cyanide complexed with metals such as Cu. The method finds particular application in removing cyanide from a tail stream from a carbon in leach (CIL) mining operation. The method of the invention is carried out by contacting an aqueous stream containing cyanide with carbon, under conditions wherein the Eh (oxygen reduction potential (ORP) measured in mV) of the aqueous stream is O or above. Advantageously the pH of the solution is buffered to from 7-9.