Hydrometallurgical Recovery of Copper Tailing Waste by Bioleaching at Hindustan Copper Limited, India

The conventional methods of refining cannot be implemented for recovery of copper from tailing waste collected from Hindustan Copper Limited, Khetri, India as it contains low copper and higher iron along with other metals present. Hence bioleaching was tested as an alternative approach for the recovery of copper from the waste. The study investigated the feasibility of using a bioleaching process for the treatment of copper tailing waste. The XRD and ED-XRF analysis confirmed that the waste contained 0.13% w/w copper, which is present in different forms including chalcopyrite (CuFeS2). Shake flask studies optimized with tailing concentration, optimum temperature, and pH showed 94.03 % w/w recovery of copper at 2 % w/v waste concentration after 40 days of exposure at pH 2.0. The study was extended to a pilot-scale glass column filled with raw copper tailing mixed with Acidithiobacillus ferrooxidans at a flow rate of 3 L h-1. A recovery of 54.71% w/w of copper was obtained by this setup. The mix-proportion clay bricks were cast with the tailing waste after bioleaching. The bricks showed better compressive strength as compared to normal bricks. A pilot scale heap leaching study with 5 kg of tailing waste mixed with Acidithiobacillus ferrooxidans showed a 64.28% w/w copper tailing in 40 days.