Pi. Harvey et Fk. Crundwell, THE EFFECT OF AS(III) ON THE GROWTH OF THIOBACILLUS-FERROOXIDANS IN AN ELECTROLYTIC CELL UNDER CONTROLLED REDOX POTENTIALS, Minerals engineering, 9(10), 1996, pp. 1059-1068
Citations number
21
Categorie Soggetti
Engineering, Chemical","Mining & Mineral Processing",Mineralogy
Thiobacillus ferrooxidans oxidises ferrous ions in solution during the
bacterial leaching process. In batch experiments that are usually per
formed to determine the kinetics of the bacterial oxidation of ferrous
ions, the concentrations of both the ferrous and ferric ions change a
s a result of the bacterial activity. This change in concentration mak
es it difficult to interpret the data from these experiments, particul
arly if the concentrations vary through reaction regimes where differe
nt mechanisms govern the bacterial activity. In this study the concent
rations of ferrous and ferric ions are maintained at their initial val
ues by controlling the redox potential of the solution in which the re
action occurs. The redox potential is controlled by reducing the ferri
c ions produced by the bacteria. In order to achieve this, the bacteri
a are grown in the cathode compartment of an electrolysis cell. The cu
rrent to the cell is varied by the controller, depending on whether mo
re or less reduction of ferric ions is required. The current required
to reduce the ferric ions in order to maintain the redox potential at
a constant value is a measure of the bacterial activity and the rate o
f bacterial growth. The effect of ferrous, ferric and arsenite concent
rations on the rate of bacterial growth are presented. It is shown tha
t growth rate is strongly dependent on the concentration of both the f
erric and the arsenite ions in solution. Copyright (C) 1996 Elsevier S
cience Ltd.