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Relationship and effect of redox potential, jarosites and extracellular polymeric substances in bioleaching chalcopyrite by acidithiobacillus ferrooxidans YU Run-lan1, 2, ZHONG Dai-li1, 2, MIAO... as mole ratio of Fe(III) to Fe(II) in the solutions containing synthetic extracellular polymeric substances (EPS). When the solution potential is lower than 650 mV (vs SHE), the inhibition of jarosites......
EPS environment for bacterial living is at about pH 1.8; the iron precipitates and jarosites formed by a lot of biologically oxidized Fe3+ cover the simulated EPS easily and form an impermeable deposit acting as a limited barrier of ion transport that attenuates the aggressiveness of the bioleaching attack. The EPS layer blocked by iron precipitates or jarosites is responsible for the chalcopyrite......
thiooxidans can prevent jarosites accumulating on the substrate and allow further copper to dissolute through the action of ferric ion. The selection of the suitable pH in a leaching solution would......
mol/L Cu2+ ions. It was inferred that the EPS with jarosites on the surface of chalcopyrite gradually acted as a weak diffusion barrier for Cu2+, Fe3+ ions transference during bioleaching chalcopyrite...], such as elemental sulphur, polysulphides and jarosites, cover the mineral surface to form a tight passivation layer which inhibits the bio-extraction of copper from chalcopyrite [1,2]. There is also......
, RACHAEL-ANNE W. A Raman spectroscopic study of selected natural jarosites[J]. Sectrochimica Acta Part A, 2006, 63(1): 1-8. [2] SMITH A M L, HUDSON-EDWARDS K A. Dissolution of jarosite [KFe3(SO4)2(OH)6... on synthetic alkali-hydronium jarosites. I: Synthesis of jarosite and natrojarosite[J]. Mineralogia Polonicam 1970, 1(1): 47–57. [10] RIPMEESTER J A, RATCLIFFE C I, DUTRIZAC J E, et al. Hydronium......
the jarosites generated during the growth of Acidithiobacillus ferrooxidans was also determined. Actively growing cultures of Thiomonas spp. and Bacillus spp. were inoculated into their respective media... oxidation of the more toxic form of arsenic, namely, arsenite to arsenate using Thiomonas spp. and Bacillus spp. 2) The role of jarosites produced by A. ferrooxidans and Leptospirillum ferrooxidans......
(4)-(5) during the initial period of bioleaching, then, the dissolution of chalcopyrite by bacteria produces sulfuric acid, iron deposits and jarosites, consequently, resulting in the gradual drop... include CuFeS2, jarosites, sulfur and FeOOH, etc, and the amount of residues such as jarosites and FeOOH of bacteria solution is higher than that of bacteria and EPS solution. This indicates that EPS......
bacterial cultures, especially in bioleaching process [10]. The jarosites are ammoniojarosites with the formula MFe3(SO4)2(OH)6, where M=K+, Na+, NH4+, Ag+, or H3O+. The formation of jarosite precipitation... and Acidithioobacillus ferrooxidan, the medium is 9K which contains a high concentration of NH4+ ions [9], and the jarosites produced are ammoniojarosites with formula NH4Fe3(SO4)2(OH)6. Abundant iron ions......
, Ag, Cd and Cu; 3) Fe and As will not be dissolved due to the near neutral pH value of the solution. FROST et al [2] studied the thermal decomposition of jarosites of potassium, sodium and lead... of jarosites of potassium, sodium and lead [J]. Journal of Thermal Analysis and Calorimetry, 2005, 82(1): 115-118. [3] S, FRIEDRICH B. Kinetics and mechanism of thermal zinc-ferrite phase decomposition......
to the formation and precipitation of iron and silver jarosites, particularly at low pulp densities. Considering the increase of recent environmental accidents at various gold recovery processes around......