two-stage technology for bacterial and chemical leaching of copper-zinc raw materials by Fe³⁺ ions with their subsequent regeneration by chemolithotrophic bacteria

A two-stage technology for bacterial and chemical leaching of nonferrous metals in a specifically designed laboratory unit has been proposed. At the first stage of leaching, ferric iron formed during the second stage of oxidation of Fe²⁺ ions by mesophilic chemolithotrophic microorganisms was used. The optimal parameters of the first stage of the process (flow rate, temperature, and the process duration) were 2 l/h, 75°C, and 24 h, respectively. The results of testing of the two-stage technology for leaching copper-zinc raw materials indicated that the depth of zinc and copper leaching can be increased from 70 to 93% and from 40 to 58.8%, respectively, and the process duration can be reduced from 120 to 24 h as compared to the commonly used one-stage technology.