Bioleaching of chalcocite by mixed microorganisms subjected to mutation

Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO₂⁻, diethyl sulfate (DES), UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms (treated with 1% DES for 60 min) with the best performance on chalcocite-leaching, increases the content of Cu²⁺ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu²⁺ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units (OTUs) in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application. Foundation item: Project(50321402) supported by the National Natural Science Foundation of China; Project(2004CB619201) supported by the Major State Basic Research and Development Program of China     

两株不同铁氧化细菌合成的沉淀差异性分析

通过ICP-AES、SEM、XRD和FTIR等方法，对不同铁氧化细菌在不同温度条件下所合成的赭黄色高铁沉淀进行了分析。结果表明：无论是嗜铁钩端螺旋菌DY菌株（Leptospirillum ferriphium），还是嗜酸氧化亚铁硫杆菌GF菌株（Acidithiobacillus ferrooxidans）合成的沉淀都是黄钾铁矾和黄铵铁矾的混合物；其中，GF合成的沉淀混合物中黄钾铁矾的含量比DY合成的黄钾铁矾约高出5．53％；而DY合成的沉淀中，黄铵铁矾的含量比GF合成的沉淀中的黄铵铁矾的含量约高出15．24％。     

某高结合率土质氧化铜矿石强化浸出试验研究

对云南某黏土质氧化铜矿进行了浸出试验研究,试验结合不同粒级矿石的可浸性能差异,对矿石进行分级强化浸出。+0.074mm添加强化浸出剂ED-1搅拌浸出,-0.074mm加温80℃搅拌浸出。通过搅拌浸出条件试验,确定最佳浸出参数,最佳条件下铜综合浸出率81.93%,吨铜综合酸耗13.86t,铜浸出率较现有常温浸出工艺有了大幅提升。     

Growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 grown on different substrates

The growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 isolated from an acid hot spring in Tengchong,Yunnan Province,China were investigated cultured on different substrates including soluble substrate ferrous sulfate and nonsoluble solid substrates S~0,pyrite and chalcopyrite.The growth characteristics of the cells in each substrate were characterized with the changes in cell number,pH,E_h,and concentrations of Fe~(2+)or SO_4~(2-),or ratios of[Fe~(2+)]to[Fe~...     

Mutagenic breeding of silver-resistant Acidithiobacillusferrooxidans and exploration of resistant mechanism

The silver-resistant Acidithiobacillus ferrooxidans were isolated from 22 acid mine drainage （AMD） samples collected from Dexing Copper Mine and Chengmen Mountain Mine, Jiangxi Province, China. Isolate DX16 is obtained from the sample taken from Dexing Copper Mine and still carries out ferrous ion oxidation when incubated in 9K medium containing silver nitrate （240 mg/L）. While isolate HI, a less resistant strain taken from Yin Mountain Mine, has a tolerate level of only 60 mg/L. Based on 16S ribosomal DNA sequencing, both bacterial 16SrDNA sequences are 100% similar to Acidithiobacillus ferrooxidans ATCC 23270. Through ultraviolet irradiation induced mutations, isolate mDX16 that is obtained from DX16 carries out ferrous ion oxidation when incubated in 9K medium containing higher concentration of silver nitrate （250 mg/L）. When silver-resistant gene （SilC） analysis is carried out on the two isolates, it is seen that this gene was absent in both.     

Influence of external circulation on sludge characteristics during start-up of internal circulation reactor

1INTRODUCTION Internalcirculation(IC)reactor,oneofthemosteffectiveanaerobicbioreactors,hasbeen widelyusedtotreatvariousindustrialeffluentsbe causeofitshighloadingrate,considerablefeasibil ity,robustresistancetooutsideaccidentsandrela tivelylowinvestmentcost,comparedtothetradi tionalupflowanaerobicsludgeblanket(UASB)re actor[110].However,ICreactoralsoappearstobesimilartootheranaerobicapparatusinatime con sumingandunstablestart upphase[1013].Thisis becauseduringtheinitialstageofstart upt…     

喜温嗜酸硫杆菌YN12菌株的鉴定及其镉抗性能

自云南酸性热泉水样中分离出一株中度嗜热硫氧化菌YN12.对其形态特征和生理生化特性以及16S rDNA序列分析结果证明,该菌株归属于喜温嗜酸硫杆菌(Acidithiobacillus caldus).重金属抗性实验表明,YN12菌株对3CdSO4-8H2O具有超强抗性,其最高初始Cd2 耐受浓度达4.8 g/L.在此基础上,不断提升3CdSO4-8H2O浓度,其最终Cd2 耐受浓度可达31.5 g /L(相当于3CdSO4-8H2O 210 g/L).在该最终Cd2 耐受浓度下,经过连续3代的适应性生长,YN12菌株的生长速度和硫氧化活性均能得到较好的恢复.     

Growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 grown on different substrates

The growth and surface properties of new thermoacidophilic Archaea strain Acidianus manzaensis YN-25 isolated from an acid hot spring in Tengchong, Yunnan Province, China were investigated cultured on different substrates including soluble substrate ferrous sulfate and nonsoluble solid substrates S^0, pyrite and chalcopyrite. The growth characteristics of the cells in each substrate were characterized with the changes in cell number, pH, Eh, and concentrations of Fe^2＋ or SO4^2- , or ratios of [Fe^2＋] to [Fe^3＋], and the surface properties were characterized and analyzed in terms of Zeta-potential, hydrophobicity, and surface FT-IR spectra of the cells. The results show that the cells grown on solid substrates have higher value of isoelectric points. They are more hydrophobic and express more surface proteins than ferrous sulfate grown cells.     

EX21OOe励磁系统故障诊断与预警优化

励磁系统的运行与发电机及电力系统稳定性息息相关。EX2100e系统是目前GE公司燃气轮机的主 流励磁 系统,该系统 、输出信息少,与国产励磁系统差异较大,不利于运行维护人员及时发现 并处理故障。针对这种 ,对该系统的保护、故障报警进行了分析梳理,并实施了故障 化方案, 提升了系统 靠性。     

铁离子对土状铜矿中铜浸出影响研究

考察Fe3+浓度、Fe3+/Fe2+对土状铜矿中铜浸出率的影响,分析了酸浸过程中铁离子提高铜浸出率的机理。结果表明,在矿浆浓度30%、酸浓度36.8g/L、12.0g/L硫酸铁溶液浸出土状矿48h后,铜浸出率为62.4%,与无铁时铜浸出率相比提高了10个百分点。其中有92.6%游离氧化铜、70.3%结合氧化铜、35.6%次生硫化铜和11.8%原生硫化铜被浸出,除原生硫化铜外,均比无铁时有明显提高。并且随着Fe2+/Fe3+的降低,铜浸出率逐渐增加。增加Fe3+浓度提高了溶液电位,从而提高铜浸出率。