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Study on Bioleaching of Chalcopyrite by Acidithiobacillus Ferrooxidans

Author: KangWenLiang
Tutor: YangHaiZuo
School: Jiangnan University
Course: Fermentation Engineering
Keywords: Bioleaching Acidophilic Thiobacillus ferrooxidans Fed-batch culture Chalcopyrite Microbial growth and metabolic Sulfide oxidation Jarosite class Sulfur - oxidizing bacteria
CLC: TF18
Type: Master's thesis
Year: 2010
Downloads: 82
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Abstract


With the large-scale development of mineral resources and ease of processing ore is dwindling, the requirements for the efficient use of low-grade ore more urgent. Bioleaching technology is the Biotechnology and smelting works cross-linking is an important method to solve the above-mentioned lack of resources, in line with the requirements of modern society, resources and environment, is a promising green metallurgy technology. Acidophilic Thiobacillus ferrooxidans (Acidithiobacillus ferrooxidans, the referred A.ferrooxidans) object, the experimental strain identification of molecular biology and study the efficient cultivation; leaching of chalcopyrite and with this strain, different leaching conditions under the leaching system differences, and identified the key factors to improve the leaching rate of chalcopyrite; finally screened from the mining site of a sulfur-oxidizing bacteria resistant to low pH, in order to carry out mixed bacteria leaching of chalcopyrite research. Extract the experimental strains cumt-1 16S rDNA sequence and the identification of molecular biology. Determine strains cumt-1 and type strain A. for strain GF by ATCC23270 kinship homology 100%. By feeding high-culture acidophilic Thiobacillus ferrooxidans. Acidophilic Thiobacillus ferrooxidans culture conditions in shake flasks, optimization, and to determine the feeding strategy is to maintain the culture medium concentration of Fe2 for 4g/L-8 g / L; then in 9K medium and sulphide medium fed-batch culture experiments strains in a substantial increase in the conversion rate and the intensity of production under the premise of not lower than the growth rate, efficient training. In 9K medium batch culture the 39h when bacteria concentrations up to 4 × 108cells/mL, and the conversion rate compared to batch culture increased by 32%, the intensity of production increased by 128%; sulfide ore medium batch culture 39h when bacteria concentration up to 6.25 × 108 cells / mL, and the conversion rate and the intensity of production increased by 80% and 259% respectively compared to batch culture. Detailed study of chalcopyrite leaching departure from microbial growth and metabolism, and the key factors that determine the effects of chalcopyrite leaching. Bioleaching and chemical leaching by comparing to determine the role of the chalcopyrite leaching microbially mediated leaching. Univariate analysis was performed to determine the 10% inoculum size allows leaching highest bacteria concentration of the oxidation of sulfide times leaving leaching rate highest for 17% of the amount of inoculation. Experimental strains used and after acclimatization for chalcopyrite leaching can leaching rate of 25%, after further be removed when inoculated into the jarosite type substances, the leaching rate is higher, at 30%. Analysis of the leaching process to determine the bacterial metabolism and the leaching system, the bacteria concentrated and jarosite substances in mineral coverage is a key factor to affect chalcopyrite leaching. Screen and identify a bioleaching microorganisms. From Fujian Zijin Mountain gold and copper industrialized yard leaching solution filter out a sulfur-oxidizing bacteria resistant to low pH ZJJN phylogenetic tree of 16S rDNA gene sequence comparison and system analysis to determine to Acidithiobacillus sp. And found that in the case of a pH of less than 1.0 there is still a certain amount of sulfur-oxidizing activity, is expected to be used for leaching of chalcopyrite.

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CLC: > Industrial Technology > Metallurgical Industry > Metallurgical Technology > Microbial metallurgical
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