排序方式: 共有81条查询结果,搜索用时 171 毫秒
41.
Baoping Xin Di Zhang Xian Zhang Yunting Xia Feng Wu Shi Chen Li Li 《Bioresource technology》2009,100(24):6163-6169
The bioleaching mechanism of Co and Li from spent lithium-ion batteries by mixed culture of sulfur-oxidizing and iron-oxidizing bacteria was investigated. It was found that the highest release of Li occurred at the lowest pH of 1.54 with elemental sulfur as an energy source, the lowest occurred at the highest pH of 1.69 with FeS2. In contrast, the highest release of Co occurred at higher pH and varied ORP with S + FeS2, the lowest occurred at almost unchanged ORP with S. It is suggested that acid dissolution is the main mechanism for Li bioleaching independent of energy matters types, however, apart from acid dissolution, Fe2+ catalyzed reduction takes part in the bioleaching process as well. Co2+ was released by acid dissolution after insoluble Co3+ was reduced into soluble Co2+ by Fe2+ in both FeS2 and FeS2 + S systems. The proposed bioleaching mechanism mentioned above was confirmed by the further results obtained from the experiments of bioprocess-stimulated chemical leaching and from the changes in structure and component of bioleaching residues characterized by XPS, SEM and EDX. 相似文献
42.
43.
目的:微生物湿法冶金技术是一种有效回收难处理常规选矿方法难以处理的复杂矿中金属的方法,本研究旨在利用该工艺处理国内某低品位(0.67%)难选铜矿,提高铜的回收率。方法:首先,从某矿山富集得到中温富集物,其次,对该矿石进行生物浸出,同时优化浸出过程工艺参数。结果:所富集得到的中温富集物最适生长温度为30℃,最适pH值为1.9。在摇瓶中浸出难选铜矿时,最佳摇床转速为180 r/min,最优充气强度为360 mL/min,10天内难选铜矿中铜的浸出率可以达到92%。结论:该中温富集物具有较好地浸出难选铜矿的能力。 相似文献
44.
Zhu W Xia JL Yang Y Nie ZY Zheng L Ma CY Zhang RY Peng AA Tang L Qiu GZ 《Bioresource technology》2011,102(4):3877-3882
The sulfur oxidation activities of four pure thermophilic archaea Acidianus brierleyi (JCM 8954), Metallosphaera sedula (YN 23), Acidianus manzaensis (YN 25) and Sulfolobus metallicus (YN 24) and their mixture in bioleaching chalcopyrite were compared. Meanwhile, the relevant surface sulfur speciation of chalcopyrite leached with the mixed thermophilic archaea was investigated. The results showed that the mixed culture, with contributing significantly to the raising of leaching rate and accelerating the formation of leaching products, may have a higher sulfur oxidation activity than the pure cultures, and jarosite was the main passivation component hindering the dissolution of chalcopyrite, while elemental sulfur seemed to have no influence on the dissolution of chalcopyrite. In addition, the present results supported the former speculation, i.e., covellite might be converted from chalcocite during the leaching experiments, and the elemental sulfur may partially be the derivation of covellite and chalcocite. 相似文献
45.
Sequence-specific bacterial growth inhibition by peptide nucleic acid targeted to the mRNA binding site of 16S rRNA 总被引:1,自引:0,他引:1
Masashi Hatamoto Kazufumi Nakai Akiyoshi Ohashi Hiroyuki Imachi 《Applied microbiology and biotechnology》2009,81(6):1161-1168
To compare oxidative dissolution rates of chalcopyrite by different consortia of moderately thermophilic acidophiles, various
defined mixed cultures of three bacteria Acidithiobacillus caldus s2, Leptospirillum ferriphilum YSK, and Sulfobacillus sp. LN and one archaeon Ferroplasma thermophilum L1 were studied in batch shake flask cultures incubated at 45 °C. Chalcopyrite dissolution was determined by measuring variations
of soluble copper, ferric iron, and pH. Microbial population dynamics involved in bioleaching process were monitored using
real-time quantitative polymerase chain reaction (PCR) technology. The complex consortia containing both chemoautotrophic
(L. ferriphilum and At. caldus) and chemomixotrophic (Sulfobacillus LN and F. thermophilum) moderate thermophiles were found to be the most efficient in all of those tested. Mutualistic interactions between physiologically
distinct moderately thermophilic acidophiles, involving transformations of iron and sulfur and transfer of organic compound,
were considered to play a critical role in promoting chalcopyrite dissolution. The real-time PCR assay was reliable to analyze
population dynamics of moderate thermophiles in bioleaching systems, and the analysis results were consistent with physiological
characteristics of these strains. 相似文献
46.
Lexian Xia Songlin Dai Chu Yin Yuehua Hu Jianshe Liu Guanzhou Qiu 《Journal of industrial microbiology & biotechnology》2009,36(6):845-851
Two sphalerite samples with different iron/sulphur (Fe/S) ratios, Shuikousan ore (Fe/S 0.2) and Dachang ore (Fe/S 0.52), were
processed using three microbial species, Leptospirillum ferriphilum, Acidithiobacillus ferrooxidans and Acidithiobacillus caldus. Following 20 days of bioleaching in shake flask cultures, a higher zinc (Zn) extraction (96%) was achieved with Shuikousan
ore than with Dachange ore (72%). The extraction efficiency increased when elemental S was added to Dachang ore to attain
the same Fe/S ratio as that for Shuikousan ore. Following the addition of S, the redox potential, pH and total dissolved Fe
for Dachang ore demonstrated similar behaviors to those of Shuikousan ore. Acidithiobacillus caldus and L. ferriphilum became the dominant species during the bioleaching of sphalerite with a high Fe/S ratio. In contrast, the dominant species
were A. ferrooxidans and A. caldus during the bioleaching of sphalerite with a low Fe/S ratio. These results show that the Fe/S ratio has a significant influence
on the bioleaching behavior of sphalerite and the composition of the microbial community. 相似文献
47.
E. L. J. Watkin S. E. Keeling F. A. Perrot D. W. Shiers M.-L. Palmer H. R. Watling 《Journal of industrial microbiology & biotechnology》2009,36(3):461-465
Selective enrichments enabled the recovery of moderately thermophilic isolates with copper bioleaching ability from a spent
copper sulfide heap. Phylogenetic and physiological characterization revealed that the isolates were closely related to Sulfobacillus thermosulfidooxidans, Acidithiobacillus caldus and Acidimicrobium ferrooxidans. While isolates exhibited similar physiological characteristics to their corresponding type strains, in general they displayed
similar or greater tolerance of high copper, zinc, nickel and cobalt concentrations. Considerable variation was found between
species and between several strains related to S. thermosulfidooxidans. It is concluded that adaptation to metals present in the bioleaching heap from which they were isolated contributed to but
did not entirely explain high metals tolerances. Higher metals tolerance did not confer stronger bioleaching performance,
suggesting that a physical, mineralogical or chemical process is rate limiting for a specific ore or concentrate. 相似文献
48.
James R. Yates John H. Lobos David S. Holmes 《Journal of industrial microbiology & biotechnology》1986,1(2):129-135
Summary Microorganisms are currently used for the recovery of copper from mining dumps of low-grade ore. One of the most important microorganisms involved in copper-solubilization isThiobacillus ferrooxidans, although many other microbial genera are also thought to be implicated. A mining dump poses some special problems for the industrial microbiologist because it represents a non-sterile and heterogeneous substrate. Consequently, to enhance our knowledge of the role of microorganisms in metal recovery we must identify the indigenous microorganisms and understand their respective contributions to the process. In addition, when a superior strain of microorganism is developed in the laboratory, by genetic engineering or by other means, we must have a method to evaluate the maintenance of such a strain in the mining dump. In this paper, we describe DNA homology studies, using dot blot and Southern blot analysis of hybridizations of both whole genomic DNA and cloned DNA sequences, to identify and enumerate several bioleaching microorganisms. We demonstrate that it is possible to identify different species of microorganisms and, in one case, to discriminate between different strains of a single species. It is also possible to identify and quantitate certain species in a mixed culture. DNA hybridization analysis has several advantages over the more conventional bacteriological methods of identification, especially in a complex bioleaching situation. 相似文献
49.
《Enzyme and microbial technology》1998,23(7-8):427-431
Ferrous iron oxidation by Thiobacillus ferrooxidans was studied in shake flasks and a bubble column under different aeration conditions. The maximum biooxidation rate constant was affected by oxygen transfer only at low aeration intensities. At oxygen transfer rates higher than 0.03 mmol O2 l−1 min−1, the maximum biooxidation rate constant was about 0.050 h−1 in both shake flasks of different size and the bubble column. The oxygen transfer rate could be used as a basis for scaling up bioreactors for ferrous iron biooxidation by T. ferrooxidans. 相似文献
50.
The loss of part of the lipopolysaccharides (LPS) of the outer membrane of T. ferrooxidans negatively influenced the attachment of the bacteria to minerals and the bioleaching process. LPS previously extracted from T. ferrooxidans and which had come into contact with pyrite inhibited the attachment of cells to minerals and also negatively affected the bioleaching. These results suggest that LPS play an important role in the attachment of the microorganisms and therefore, its presence or absence could affect the bioleaching process. 相似文献