Arsenic in the Copper Mining Industry

摘要

The aim of the present paper is to review the current technologies for arsenic removal in the copper metallurgical industry, and to show the progress made with some promising emerging strategies, involving the pre-treatment of copper-arsenic concentrates by selective flotation or by alkaline leaching with Na2S-NaOH solutions. The advantages of alkaline leaching are the selective dissolution of arsenic and antimony, the high extraction yield, and the practically nil loss of copper, which remains in the clean copper concentrate as a CuS residue. Alkaline "cured"-a procedure similar to "acid-cured" in conventional leaching improves arsenic extraction and reagent consumption,making this an interesting technology for the treatment of high As-Sb concentrates.In light of recent advances on the selective flotation of enargite and tennantite, the importance of redox conditions to control the flotation/depression of enargite-tennantite from copper sulfides has been well established. However, problems of selectivity must still be solved. Additionally, the limitation imposed in some cases by the need to recover the molybdenum by-product must be considered.The application of selective flotation to obtain a high-arsenic or "dirty" concentrate and its subsequent treatment by the alkaline leaching process is suggested.