Column Bioleaching of Low-Grade Chalcopyritic Ore Using Moderate Thermophile Bacteria

Abstract

Bacterially assisted heap leaching is an economical technology for treating low grade copper sulphides. In the present research, bioleaching of low grade chalcopyrite ore (1% chalcopyrite, and 3% pyrite) have been investigated using moderate thermophilic bacteria. The ore sample has low solubility in acid solution (about 5%). Experiments were carried out using column reactors and the effect of particle size (−12.7, −19.07 and −25.04 mm) and external addition of carbon dioxide to the induced air (10% v/v) have been investigated. Results have shown that the copper recovery increased with reducing particle size, and carbon dioxide addition improved bacterial activity and copper dissolution. In the optimum condition, i.e., particles finer than 12.07 mm and 10% (v/v) carbon dioxide addition, 69.68% of copper were extracted.

Keywords:

• bioleaching
• low grade ore
• copper
• moderate thermophile
• bacteria
• column reactor

ACKNOWLEDGMENT

This work was supported by the National Iranian Copper Industry Company (NICICO)