Bioleaching of refractory gold concentrates at high pulp densities in a nonconventional rotating-drum reactor

Herrera, M. N. ; Escobar, B. ; González, C. ; Parra, N. ; Vargas, T.
Organization: Society for Mining, Metallurgy & Exploration
Pages: 5
Publication Date: Jan 1, 1999
The bioleaching of mineral sulfide pulps in a bench-scale rotating-drum reactor was studied. The reactor contained horizontal paddles on the inner wall for lifting the mineral pulp. The performance of the reactor was tested by bioleaching a refractory pyritic gold concentrate in the presence of pure Thiobacillus ferrooxidans (ATCC 19859). The concentrate was efficiently bioleached at a 50% pulp density with the drum operating at from 0.5 to 1.0 rpm. Attempts at bioleaching the concentrate at the same pulp density used in a conventional stirred reactor showed severe inhibition of bacterial activity. The results demonstrated that the drum reactor allows the process to operate at much higher pulp densities than conventional stirred-tank reactors. This results in improved bacterial activity because of better attrition control of the mineral particles.
Full Article Download:
(336 kb)