Well-controlled column bioleaching of a low-grade copper ore by a novel equipment

For the low-grade copper sulfide ores with 0.99% of copper, of which 41.5% was primary copper sulfide, and 54.5% was secondary copper sulfide, well-controlled column bioleaching on a novel equipment was carried out to investigate the optimal conditions of pre-leaching, particle sizes of ores, temperature, spray intensity and strain consortium. Results show that copper extraction of 91.11% can be obtained after 90 d with the optimal pH value of pre-leaching of 0.8; the pH values of pre-leaching significantly affect the final copper extractions. Copper extractions of 93.11%, 91.04% and 80.45% can be obtained for the bioleaching of ores with particles size of 5–8 mm, 5–15 mm and 5–20 mm, respectively. Copper extractions are 83.77% and 91.02% for bioleaching under the conditions of room temperature and 35 oC. Copper extractions are 77.25%, 85.45% and 91.12% for the bioleaching when flow rate of spray was 5 L/(h·m2), 10 L/(h·m2) and 15 L/(h·m2), respectively. Additionally, the strain consortium C3 is the best among the four strain consortia in bioleaching. By considering the energy consumption, the optimal conditions of bioleaching in this work are determined as pH of pre-leaching of 0.8, particles size of 5–15 mm, temperature of 35 °C, spray intensity of 15 L/(h·m2), and strain consortium C3.