Migration of arsenic(III) during bacterial oxidation of arsenopyrite in chalcopyrite concentrate by Thiobacillus ferrooxidans

1992 ◽  
Vol 38 (3) ◽  
pp. 429-431 ◽  
Author(s):  
Martin Mandl ◽  
Pavlína Matulová ◽  
Hana Dočekalová
1978 ◽  
Vol 24 (7) ◽  
pp. 888-891 ◽  
Author(s):  
Arpad E. Torma

The bacterial oxidation of a naturally occurring gallium-bearing chalcopyrite concentrate and a pure synthetic gallium (III) sulfide has been investigated at pH 1.8 and 35 °C, using an active culture of Thiobacillus ferrooxidans. This oxidation process may proceed by direct or by indirect bacterial action. The highest dissolved gallium and copper concentrations were about 2.2 and 40.2 g/ℓ respectively. The order of the specific rate of oxygen uptake by T. ferrooxidans is approximately CuFeS2[Formula: see text] gallium-bearing CuFeS2 > FeS2 > CuS > Cu2S > Ga2S3.


1995 ◽  
Vol 17 (2) ◽  
pp. 229-232 ◽  
Author(s):  
Takami Kai} ◽  
Makoto Nishi ◽  
Takeshige Takahashi

1992 ◽  
Vol 108 (2) ◽  
pp. 129-133
Author(s):  
Naoki HIROYOSHI ◽  
Masami TSUNEKAWA ◽  
Tsuyoshi HIRAJIMA ◽  
Takakatsu TAKAMORI

1990 ◽  
Vol 106 (4) ◽  
pp. 173-179
Author(s):  
Takakatsu TAKAMORI ◽  
Keiko SASAKI ◽  
Masami TSUNEKAWA ◽  
Tsuyoshi HIRAJIMA

1999 ◽  
Vol 65 (12) ◽  
pp. 5285-5292 ◽  
Author(s):  
T. A. Fowler ◽  
F. K. Crundwell

ABSTRACT This paper reports the results of leaching experiments conducted with and without Thiobacillus ferrooxidans at the same conditions in solution. The extent of leaching of ZnS with bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, while no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T. ferrooxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.


Author(s):  
Ravindra Pogaku ◽  
Bharathi Kodali

Nickel bioleaching from copper flotation concentrate assumes greater significance because of its value and not many studies are carried out in these lines. Hence, nickel leaching was attempted and several process parameters of bacterial oxidation for copper flotation concentrate were examined for optimization. The parameters considered for shake flask leaching experiments were temperature, pulp density, particle size, agitation, residence time and inoculum size. The effect of variable proportions of each parameter on nickel leachability was studied. Optimum values of pulp density (10%) and agitation (140 rpm) played an important role in controlling the mass transfer resistance during leaching process. Increase in temperature from 27oC to 30oC has accelerated the bacterial oxidation process while initial concentration of inoculum (1-10%) has not shown considerable variation in nickel leachability. A particle size of ±60#size was found to be essential for bacterial attack. Maintenance of optimum conditions of leaching has yielded considerable nickel recovery (55%) compared to low recovery under unoptimal conditions.


Author(s):  
V.K. Berry

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.


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