温度对浸矿微生物活性及铜浸出率的影响

研究了从紫金山铜矿生物堆浸矿堆中分离出来的浸矿菌群在不同温度下的氧化活性和对紫金山硫化铜矿石的浸出规律,并利用变性梯度凝胶电泳法研究了15℃和30℃的菌群组成情况.结果表明:所分离的细菌的最佳生长温度为30℃,浸出10d,铜浸出率为87.62%,在最佳生长温度以外铜浸出率都会降低;15℃和30℃的优势菌分别为Leptospirillum fer-riphilum和Acidithiobacillus thiooxidans,两个温度下均有同一种劣势菌Acidithiobacillus caldus;优势菌种随温度的变化是与菌种的性质相关的.     

中度嗜热混合菌在搅拌槽中浸出黄铜矿及其群落动态

为了优化浸出工艺,研究浸矿体系中主要微生物种群的结构和动态变化,在槽式搅拌反应器中于45℃用中度嗜热混合菌(Acidithiobacillus caldus,Leptospirillum ferriphilum,Sulfobacillus acidophilus,Sulfobacillus thermosulfidooxidans等)浸出黄铜矿精矿,考察浸出液的pH,电极电位Eh及金属离子浓度并应用PCR-RFLP(限制性酶切片段长度多态性)方法研究细菌群落变化,浸出时间为30d。研究结果表明:Cu的浸出率为26.2%,反应器内菌种多样性不丰富,只有At.caldus和L.ferriphilum2种;群落动态变化明显,在浸出开始阶段At.caldus是优势种群,其丰度为96%,随着浸出的进行,L.ferriphilum逐渐增多,在浸出后期代替At.caldus成为优势种群,其丰度为69%。     

某铀矿细菌菌群柱浸过程中的硫强化作用及其机理分析

评估了由Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans和Leptospirillum ferriphilum组成的混合菌群在柱式反应器中浸出某复杂铀矿的硫强化作用及其可行性。在77 d细菌柱浸过程中,硫强化(8 g/kg)后,铀的浸出率达到了约83.61%,与对照组相比,增加了10%。利用扫描电镜和X射线荧光光谱仪对矿渣进行了表征,结果表明硫强化后的矿渣表面有细菌侵蚀的痕迹且孔隙度增大。细菌群落分析表明,硫强化后浸出液中的优势种群从Leptospirillum ferriphilum转变为Acidithiobacillus ferrooxidans,且Leptospirillum ferriphilum在下层矿石表面占比从强化前的4.3%增加到了40.74%,和Acidithiobacillus thiooxidans保持了较好的平衡。此外,动力学分析表明,铀矿细菌柱浸动力学模型更遵循了通过中间产物层控制的内部扩散模式,且硫强化能够增强铀的浸出动力学。最后,建立了一个与细菌群落和化学反应相关联的硫强化生物浸铀的机制模型。     

浸矿微生物共培养体系在氟胁迫下的基因调控机理探索

为了探明混合浸矿微生物的耐氟性能及其基因调控机理,应用功能基因芯片(FGA-Ⅱ)研究了5株浸矿细菌(Acidithiobacillus ferrooxidans ATCC 23270,Leptospirillum ferriphilum YSK,Sulfobacillus thermosulfidooxidans ST,Acidithiobacills thiooxidans A01,Acidithiobacills caldus S1)所构成的共培养体系在4.8 mmol/L氟胁迫下的基因表达谱.结果表明,该共培养体系中与氟胁迫相关的基因主要涉及到硫代谢、细胞膜、电子传递、解毒、碳固定、氮代谢等多个方面功能的代谢途径,而且各个途径在短时间(60 min)氟胁迫倾向于高效表达,而长时间(120 min)氟胁迫各个途径更倾向于低效表达.芯片图谱分析表明,氟胁迫下共培养体系中起主导调节作用的是其中的优势种群,但是劣势种群在氟胁迫时很大程度上辅助了优势种群的生长及其氧化活性的保持.     

组合浸矿细菌菌群的氧化特性及其群落结构分析

为了探究组合浸矿细菌菌群的氧化特性及其群落结构,构建4株浸矿细菌(Acidithiobacillus ferrooxidans ATCC 23270,Leptospirillum ferriphilum YSK,Acidithiobacills thiooxidans A01,Acidithiobacills caldus S1)的组合浸矿菌群.实验结果表明:此组合浸矿细菌菌群中的菌体具有较高的生物活性,表现出良好的的铁、硫氧化能力.并采用实时荧光定量PCR技术对菌群的群落结构进行了分析.结果表明:此体系中A.ferrooxidans ATCC 23270、A.thiooxidans A01是优势种群;L.ferriphilum YSK和A.caldus S1是劣势种群.     

采用氧化焙烧-酸浸法从高碳石煤中提钒试验研究

针对广西某难浸高碳石煤,比较相同焙烧和酸浸条件下静态焙烧矿和流态化焙烧矿钒的浸出率,优化流态化焙烧矿的酸浸条件。研究结果表明:流态化焙烧矿酸浸钒的浸出率比静态焙烧矿酸浸钒的浸出率平均高24%,所以,在相同焙烧温度、时间下流态化焙烧较静态焙烧更利于钒的浸出;在液固质量比为0.8:1.0,二氧化锰添加量为3%和氢氟酸添加量为2%的条件下,得最佳酸浸条件,即酸矿质量比为0.4:1.0,浸出温度为150℃,浸出时间为6 h,在此最佳酸浸条件下,钒浸出率可达88.26%。     

含砷低品位硫化铜矿生物柱浸实验

介绍了含砷低品位硫化铜矿柱浸实验研究方法、装置和结果.实验在八根有机玻璃柱浸系统中进行,考察了细菌种类、矿石粒度、供氧条件及浸出周期等参数对浸出率的影响.结果表明,在-12mm粒度下,采用Z08090-O菌株浸出,浸出167d,铜浸出率为80.75%.对含大量黄铁矿且耗酸脉石少的矿石,酸的累积降低了采用普通驯化浸矿菌的铜浸出率,但采用激光诱变获得的耐低pH值浸矿菌,能够保持高效的铜浸出率.     

高温浸矿菌sulfolobus的生长及浸矿性能

系统地研究了耐高温菌sulfolobus的生长特性.sulfolobus在65℃以上能良好地生长,并对亚铁和元素硫均具有较好的氧化作用;在75℃时,sulfolobus氧化Fe2 和元素硫的活性最强,细菌的生长曲线和细菌氧化Fe2 和元素硫的趋势一致.给出了细菌生长过程溶液SO2-4和pH的变化趋势;以黄铜矿精矿为培养基对sulfolobus进行了适应性培养,并在75℃下进行了黄铜矿摇瓶浸出研究.结果显示:适应性驯化后的sulfolobus在黄铜矿精矿上生长与浸矿性能良好;当矿浆质量分数在10%以下,浸出150h,Cu浸出率可达90%以上;而矿浆质量分数在15%以上时,浸出350h,浸出率仅80%.同时还研究了浸出体系溶液氧化还原电位Eh和pH随时间的变化规律.     

产氨细菌浸出碱性氧化铜矿

采用产氨菌种Providencia JAT-1,对云南某矿高碱性氧化铜矿进行氨浸体系下的摇瓶浸出试验.结果显示温度、矿浆液固质量比、助浸剂种类、助浸剂浓度以及细菌初始接种浓度对铜浸出率具有显著影响.在温度为30℃、矿浆液固质量比7:1、助浸剂硫酸铵浓度0.024 mol·L-1以及细菌初始接种浓度20%的条件下,产氨细菌浸出碱性氧化铜矿144 h后铜浸出率可达42.35%.通过对浸渣铜物相分析发现矿石中次生硫化铜浸出率最高.     

五种典型浸矿微生物的耐氟性状对比研究

在微生物冶金体系中,浸矿环境的压力很可能超出了浸矿菌种的耐受能力,提高浸矿菌种的耐受性是一个极具挑战性的难题.氟化物对微生物的生长具有很强的抑制或杀死作用.在本文所研究的五种浸矿细菌中,A.ferrooxidans的氟耐受性是最好的,其次是A.thiooxidans,再次是L.ferriphilum与A.caldus,最差的是S.thermosulfidooxidans.由此看出,中度嗜热浸矿菌比常温浸矿菌更容易被氟离子抑制.     

Bioleaching of chalcopyrite and bornite by moderately thermophilic bacteria: an emphasis on their interactions

Interactions between chalcopyrite and bornite during bioleaching by moderately thermophilic bacteria were investigated mainly by X-ray diffraction, scanning electron microscopy, and electrochemical measurements performed in conjunction with bioleaching experiments. The results showed that a synergistic effect existed between chalcopyrite and bornite during bioleaching by both Acidithiobacillus caldus and Leptospirillum ferriphilum and that extremely high copper extraction could be achieved when chalcopyrite and bornite coexisted in a bioleaching system. Bornite dissolved preferentially because of its lower corrosion potential, and its dissolution was accelerated by the galvanic current during the initial stage of bioleaching. The galvanic current and optimum redox potential of 390-480 m V vs. Ag/Ag Cl promoted the reduction of chalcopyrite to chalcocite(Cu2S), thus accelerating its dissolution.     

Bioleaching of chalcopyrite and bornite by moderately thermophilic bacteria：an emphasis on their interactions

Interactions between chalcopyrite and bornite during bioleaching by moderately thermophilic bacteria were investigated mainly by X-ray diffraction, scanning electron microscopy, and electrochemical measurements performed in conjunction with bioleaching experiments. The results showed that a synergistic effect existed between chalcopyrite and bornite during bioleaching by bothAcidithiobacillus caldus and Leptospirillum ferriphilum and that extremely high copper extraction could be achieved when chalcopyrite and bornite coexisted in a bioleaching system. Bornite dissolved preferentially because of its lower corrosion potential, and its dissolution was accelerated by the gal-vanic current during the initial stage of bioleaching. The galvanic current and optimum redox potential of 390?480 mV vs. Ag/AgCl pro-moted the reduction of chalcopyrite to chalcocite (Cu2S), thus accelerating its dissolution.     

Linking leach chemistry and microbiology of low-grade copper ore bioleaching at different temperatures

The effects of temperature on chalcocite/pyrite oxidation and the microbial population in the bioleaching columns of a low-grade chalcocite ore were investigated in this study. Raffinate from the industrial bioleaching heap was used as an irrigation solution for columns operated at 20, 30, 45, and 60℃. The dissolution of copper and iron were investigated during the bioleaching processes, and the microbial community was revealed by using a high-throughput sequencing method. The genera of Ferroplasma, Acidithiobacillus, Leptospirillum, Acidiplasma, and Sulfobacillus dominated the microbial community, and the column at a higher temperature favored the growth of moderate thermophiles. Even though microbial abundance and activity were highest at 30℃, the column at a higher temperature achieved a much higher Cu leaching efficiency and recovery, which suggested that the promotion of chemical oxidation by elevated temperature dominated the dissolution of Cu. The highest pyrite oxidation percentage was detected at 45℃. Higher temperature resulted in precipitation of jarosite in columns, especially at 60℃. The results gave implications to the optimization of heap bioleaching of secondary copper sulfide in both enhanced chalcocite leaching and acid/iron balance, from the perspective of leaching temperature and affected microbial community and activity.     

螺旋状专性化能自养铁氧化细菌ML-04菌株的分子鉴定

对1株螺旋状专性化能自养铁氧化细菌ML-04的16S rDNA基因PCR扩增产物进行了序列分析，并以16Sr DNA序列同源性为基础构建系统发育树，结果表明，ML-04菌株与氧化亚铁钩端螺旋菌(Leptospirillum ferrooxidans)具有较大的差异性，而与嗜铁钩端螺旋菌(Leptospirillum ferriphilum)的相似度达99．7％以上，属于同一类群．     

某铀矿石微生物浸出性能及影响因素研究

为评估微生物浸出某铀矿石的应用前景,设计正交实验,在不同初始pH值、接种量、浸出时间和固液比条件下,分别开展了嗜铁钩端螺旋菌、嗜酸氧化亚铁硫杆菌和嗜酸喜温硫杆菌浸出某铀矿石的研究。三株微生物对某铀矿石的最高浸出率均高于97%。浸出过程中,微生物浸出体系的pH值均呈下降趋势,Eh值均呈上升趋势。初始pH值、接种量、浸出时间和固液比四个因素对三株微生物的浸出均有影响,但对不同微生物浸铀的影响存在区别。影响嗜铁钩端螺旋菌浸出的主要因素是接种量,而嗜酸氧化亚铁硫杆菌和嗜酸喜温硫杆菌的浸出主要受初始pH值的影响。     

Triton X-100对氧化亚铁硫杆菌氧化活性及浸出黄铜矿的影响

为提高黄铜矿的微生物浸出效果,研究了非离子表面活性剂Triton X-100对氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)氧化Fe2+和S0的活性以及浸出黄铜矿的影响,并采用XRD对浸出后的产物进行了表征.结果表明,Triton X-100对氧化亚铁硫杆菌氧化Fe2+有一定的抑制作用,而对氧化S0则显现出促进作用;Triton X-100可显著改善黄铜矿的微生物浸出效果,当其质量浓度为30 mg·L-1时,黄铜矿中铜的浸出率提高了52.15%.Triton X-100的加入提高了氧化亚铁硫杆菌对黄铜矿浸出过程中间产物硫的生物利用性和消解作用,从而提高了浸出体系中细菌浓度和Fe3+浓度,进而促进了黄铜矿的溶解.     

柠檬酸强化黄铜尾矿的生物浸矿

通过摇瓶试验研究混合硫杆菌浸出黄铜矿尾矿砂,并初步探讨不同矿浆质量浓度和柠檬酸质量浓度对浸提实验的影响。研究结果表明,添加柠檬酸在一定质量浓度范围内对黄铜矿尾矿砂的硫杆菌浸提有促进作用。在整个浸提实验中,浸矿效率最高达到44.8%,溶液中柠檬酸质量浓度和矿浆质量浓度都会直接影响细菌的氧化活性和浸矿效果。