Influence of CO2 supplementation on bioleaching kinetics in stirred tank reactor (STR)

Anne-Gwenaëlle Guezennec (1) , Catherine Joulian (1) , Jérome Jacob (1) , Françoise Bodénan (1) , Patrick d'Hugues (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

In bioleaching processes using autotrophic bacteria, CO2 is the carbon source for the growth of the microorganisms and its availability is dependent on gas mass transfer in the bioreactor. In this study the demand in CO2 was investigated during bioleaching of several sulfidic materials (pyritic tailings, Cu concentrate, coal waste) in STR using the " BRGM-KCC " bacterial consortium. The results show (i) that Fe oxidation (and thus microbial activity) is delayed when air is injected without CO2-supplementation, and (ii) that CO2-supplementation improves leaching kinetics. The study proposes also a methodology to determine G/L transfer components and to asses CO2 limitations in the system. It shows that the microorganisms are not only sensitive to the transfer rate of CO2 from the gas to the liquid phase, but also to the availability of CO2 in solution.

Keywords: carbon dioxide; Key-words: bioleaching; CO2-supplementation; mass transfer; sulphide

Domains: Engineering Sciences [physics]; Chemical and Process Engineering

Anne-Gwenaëlle Guezennec, Catherine Joulian, Jérome Jacob, Françoise Bodénan, Patrick d'Hugues. Influence of CO2 supplementation on bioleaching kinetics in stirred tank reactor (STR). Biohydrometallurgy '18, Jun 2018, Windhoek, Namibia. ⟨hal-01784525⟩