Bioleaching of copper from smelter dust in a series of airlift bioreactors

摘要

Bioleaching of copper from the flue dust of the Sarcheshmeh copper smelter has been investigated. A series of continuous tests were carried out in two-stages of airlift bioreactors inoculated with the acidophilic, iron and sulfur oxidizing bacteria, initially derived from acid mine drainage. The effects of different parameters such as pulp density, retention time and temperature on the mesophile bioleach performance of the copper sulfide rich dust were evaluated after pre-leaching with dilute acid. Pulp densities of 2 percent and 4 percent gave the same oxidation-reduction potential in both reactors. However, increasing the average pulp density to 7 percent generated an unstable oxidation-reduction potential in the first bioreactor at 34 deg C. Overall copper extractions calculated for 2 percent , 4 percent and 7 percent pulp densities were 90 percent , 89 percent and 86 percent with mean retention times of 2.7,4 and 5 days, respectively. The process is net acid consuming and has the potential for further development and feasibility studies.