Implementation of a Comprehensive Flotation and Bioleaching Processes to Recover Copper from Low-Grade Ore Sample

Recovering copper from low-grade copper sulfide ore in an environmentally friendly way is a challenge. In this article, a comprehensive process to produce copper concentrate by enriching a low-grade sample from Meyduk copper mine with average grades of 0.07%Cu and 4.75%Fe was studied. The main operations of the process include milling, flotation, and bioleaching. The required sample was prepared from mine tailings. After preparing the sample, the sample characteristics were determined through various XRF, multi-element and chemical, X-ray diffraction and FTIR analyses, and then different flotation and bioleaching experiments were performed. In the flotation tests, effective parameters, including pH, type of collector, amount of collector, amount of depressant and amount of frother agent, were investigated. The flotation results showed that by grinding the sample to < 75 microns, increasing the pH to about 11.5 and using sodium silicate at a rate of 1000 g/ton, C4132 collector at a rate of 30 g/ton and MIBC frother agent in the amount of 30 g/ton, a concentrate with a weight percentage of 11.6, total copper grade of 0.54% and recovery of 89.8% was obtained. In the cleaner stage, with a concentrated cleaner stage with 10.3 wt.%, the copper grade was 0.77% and the recovery was 79.52%. The iron grade in the cleaner concentrate was determined to be 12.45%, and due to the high amount of pyrite in the cleaner concentrate, by bioleaching and mesophilic bacteria type, after 50 days there was a solid percentage of 10% without the addition of sulfur and bivalent iron. About 96.5% of the copper contained in the solution was recovered. The iron concentrate in the final solution was 86.5 g/L, and the copper concentrate was 0.82 g/L.