Bioleaching of Arsenic-Bearing Copper Ores

Abstract

Abstract:World copper (Cu) production has been strongly affected by arsenic (As) content, because As-rich Cu concentrates are not desirable in the metal foundries. When As-rich Cu concentrates are processed by smelting they release As as volatile compounds into the atmosphere and inside furnaces, generating serious risks to human health. In recent years, exports of Cu concentrates are being penalized for the increasingly high As content of the ores, causing economies that depend on the Cu market to be seriously harmed by this impurity. In the last few decades, biohydrometallurgy has begun to replace the traditional Cu sulfide processing, however bioleaching processes for As-bearing Cu ores which contain enargite are still in the development stage. Researchers have not yet made successful progress in enargite bioleaching using typical mesophilic and thermophilic bacteria that oxidize sulfide. New approaches based on direct oxidative/reductive dissolution of As from enargite could result in significant contributions to Cu biohydrometallurgy. Thus, As-rich Cu concentrates could be pre-treated by bioleaching, replacing current technologies like roasting, pressure leaching and alkaline leaching by selective biological arsenite oxidation or arsenate reduction. In this article, we review the As problem in Cu mining, conventional technologies, the biohydrometallurgy approach, and As bioleaching as a treatment alternative.

Behavior of As/AsxSy in Neutral and Oxidizing Atmospheres at High Temperatures—An Overview

“…Prior to pyrometallurgical processes, the ore processing with increasing arsenic contents establishes new restrictions, as the concentrate to be produced must maintain the same low levels of contamination in order to avoid penalties imposed by the market [3][4][5].…”

Bio Hydrometallurgical Technology, Application and Process Enhancement

“…Aspergillus Niger and Penicillium Simplicissimum are both used to leach sulfide minerals like copper with mobilization rate of 65% and aluminum, nickel, lead and zinc by more than 95% mobilization rate. Thiobacillus and Leptospirillum are characterized by the oxidation of sulphide minerals in acidic environment and temperature values less than 35°C, with regard to area of application these two are mostly used in dump and tank leaching of metal from sulphide based mixed ores [20,21]. The other group of genus Sulphobacillus used under the same areas of application but relatively higher temperature up to 60°C, the temperature reaches up to 90°C in case of genera Sulpholobus and Acidianus, Organotrophic microorganisms like yeast, fungi and algae which destruct sulphide mineral and aluminum silicate, facilitate bio sorption of metals that solubilize gold, these microorganism uses carbonate and silicate ore for the extraction of metals and selective gold extraction from ore floatation and metal solution.…”

Hydrometallurgical Recovery of Copper Tailing Waste by Bioleaching at Hindustan Copper Limited, India

“…In the last three decades, bioleaching has emerged as a frontier technology for mineral ore processing in general and low metal-containing ores in particular [6]. The strategy has been applied for the extraction of nickel, zinc, gold, uranium, copper, and many other metals from low-grade ores or tailings [7,8].…”