BACTERIAL LEACHING OF ZINC FROM FLOTATION TAILINGS

Abstract

Bacterial leaching of zinc from flotation tailings of the Zawar Mines Plant, Udaipur, India was investigated in the laboratory using Thiobacillus ferrooxidans in batch experiments. With pH maintained in the range of 3 to 4, zinc extraction was 70-78% in 24-28 days at 5% pulp density. Zinc extraction due to bacterial leaching was about 60% as much as with combined chemical and bacterial leaching. Settled raw sewage appeared to be a good source of nutrients (nitrogen and phosphorous) for bacterial leaching and a 2:1 sewage-tap water mixture at pH 4 produced 65% zinc extraction in 28 days.