鄂西某高磷鲕状赤铁矿磁化焙烧及浸出除磷试验

针对鄂西某高磷鲕状赤铁矿(铁品位43.50%),在实验室条件下采用磁化焙烧—磁选工艺获取铁精矿,并对该铁精矿进行酸浸、生物浸出除磷试验。研究结果表明,在焙烧温度850℃,焙烧时间25min,还原剂用量为矿石质量的5%,磨矿时间4min,磁场强度120kA/m条件下,得到铁精矿铁品位为54.92%,铁回收率为86.78%,P含量为0.83%;酸浸试验中矿浆浓度2%,分别用0.1mol/L的H2SO4,HNO3,HCl,草酸(C2H2O4),柠檬酸(C6H8O7)除磷,其中H2SO4除磷提铁效果最佳,铁精矿品位为57.98%,回收率为96.47%,除磷率为95.30%;生物浸出试验中矿浆浓度2%,用嗜酸氧化亚铁硫杆菌(At.f菌)对铁精矿作用后,磷含量为0.23%,用黑曲霉菌滤液对铁精矿作用后,磷含量为0.20%。     

氧化亚铁硫杆菌浸出废弃线路板中金属铜的研究

利用从硫化矿山分离得到氧化亚铁硫杆菌GZY-1菌株,进行了废弃线路板粉末中金属铜的浸出实验,并对浸出机理进行了分析,同时对浸出体系的pH值、氧化还原电位和细菌数量的变化进行了研究.结果表明:细菌具有将Fe2+不间断地氧化成为Fe3+的生物学特性;在浸出温度30℃及pH值1.32、液固比10∶1、搅拌速率500 r/mi...     

中温嗜酸硫杆菌浸出低品位硫化铜矿

研究了中温嗜酸硫杆菌的生长条件, 对黄铜矿进行了细菌浸出试验研究。研究表明, 中温嗜酸硫杆菌最适宜的生长条件为: pH值为2, 温度为30±1 ℃, 此条件下细菌浓度为2.24×10⁷个/mL。接种量、矿浆浓度对黄铜矿中铜的浸出率有显著的影响, 随着接种量的增加, 铜的浸出率提高。在相同浸出时间内, 矿浆浓度5%左右时, 黄铜矿中铜的浸出率最高。低品位硫化铜矿柱浸试验结果表明: 细菌浸出75 d, 铜的浸出率为45%。     

硫杆菌的耐高砷诱变及对高砷铜精矿的浸出

为提高硫杆菌浸出铜过程中的耐砷能力，对用高砷铜精矿驯化的中温硫杆菌进行了紫外线耐高砷诱变，选育出的中温硫杆菌耐砷能力达8．0g／L，而未经诱变的对照菌只能在As^3＋含量小于1．0g／L的环境中生长繁殖。用选育出的耐砷诱变菌对含As3％-8％的高砷铜精矿进行铜的细菌浸出试验，结果表明。精矿粒度为-250目、矿浆浓度为10％-15％、砷含量不超过5％的铜精矿细菌浸出效果较好，铜浸出率可达77％以上；添加Ag^＋和对浮选铜精矿进行脱药处理均能不同程度地强化细菌浸出效果。     

磁搅拌反应器中铁闪锌矿精矿的生物浸出

采用磁搅拌反应器研究铁闪锌矿精矿的生物浸出过程。结果表明，通气条件可以促进氧化亚铁硫杆菌的生长和提高其生物活性，从而加速铁闪锌矿的溶解速率，而矿浆浓度增加则增大对菌株的剪切力，导致铁闪锌矿的浸出速率降低，但适当提高矿浆浓度可以提高单位时间内锌的浸出量。与摇瓶浸出比较，在磁搅拌反应器等较大型反应器中，通气条件和矿浆浓度等因素对铁闪锌矿的生物浸出影响更为显著。     

Statistical analysis of bioleaching copper,cobalt and nickel from polymetalic concentrate originating from Kamoya deposit in the Democratic Republic of Congo

The effects of five parameters, temperature, pH, leaching duration, stirring speed and pulp density on the bioleaching of copper, cobalt and nickel from a polymetallic flotation concentrate were investigated. The leaching was carried out according to the L₂₅ (5⁵) orthogonal design. The optimal values of the parameters were determined using a Taguchi method through signal-to-noise analysis. ANOVA was applied to verify the individual contribution of each parameter and their degree of significance. It was found out that pulp density was the most influential factor on the bioleaching yield of the three metals altogether, followed by pH and temperature. For the copper bioleach, the following optimal parameters were determined: temperature – 37.5 °C, pH 1.6, leaching duration – 20 days, stirring speed – 350 rpm and pulp density – 7.5%. Verification experiments conducted according to these optimal parameters brought copper yield of 72.6%. For the cobalt bioleach, SEM observations of pure carrolite indicated a progressive bacterial colonization of mineral surface with time.     

氧化亚铁硫杆菌浸出高硫煤矸石中硫的试验研究

采用实验室自主分离筛选出的氧化亚铁硫杆菌,通过恒温水浴振荡器浸出煤矸石中的硫,研究了该菌株对高硫煤矸石中硫的脱除效果,主要考察了矿浆浓度、温度、振动条件以及时间等因素对微生物脱硫的影响。试验研究结果表明:在矿浆浓度20%,温度30℃,浸出时间8周,静态条件下,利用氧化亚铁硫杆菌处理煤矸石,可使煤矸石中硫由原来的8.47%降低为1.62%,降硫率为80.87%,其中无机硫降低了83.96%,有机硫降低了63.85%。     

细菌浸出硫化锌矿氧化动力学研究进展

综述近年来氧化铁硫杆菌浸出硫化锌矿的反应机理及其氧化动力学的研究进展概况。对氧化铁微螺菌和氧化铁硫杆菌混合菌种浸出硫化锌矿物的机理做了分析。并对开展混合菌浸出硫化锌矿的动力学模型研究提出建议。     

Bioleaching capacity of an extremely thermophilic culture for chalcopyritic materials

A thermophilic culture specific to bioleaching chalcopyritic materials has been obtained from a typical chalcopyritic copper concentrate of the Spanish Pyritic Belt. This paper shows the effect of pulp density (w/v) on bioleaching culture capacity with respect to this copper concentrate. The results of the batch tests show that it is possible, operating at 10% of pulp density to attain copper extraction of 94% in 10 days and, at higher pulp densities (20%), to attain good copper extraction (80%) in only 14 days. In the same way, the culture has been amply tested with different chalcopyritic ores and copper concentrates. The results obtained with four of these materials, two refractory gold ores and two copper concentrates are also presented. These results show a varying and versatile bioleaching capacity of this bacterial culture. A model of bacterial attack of this culture to leach chalcopyrite is postulated.     

磁黄铁矿和黄铁矿的生物浸出研究

研究了磁黄铁矿和黄铁矿的细菌浸出脱硫。研究表明, 酸性溶液中磁黄铁矿比黄铁矿更容易溶解, 其浸出脱硫率比黄铁矿的高。细菌的氧化作用使磁黄铁矿和黄铁矿的脱硫率明显升高, 且随浸出时间的增长,脱硫速度也明显加快。磁黄铁矿细菌浸出的最大脱硫率达65.65%, 比无菌浸出时提高了23.57个百分点; 而黄铁矿细菌浸出的脱硫率最高达50.49%, 比无菌浸出时提高了17.29个百分点。生物浸出磁黄铁矿的过程中存在细菌的直接作用。     

氧化亚铁硫杆菌培养条件的优化

氧化亚铁硫杆菌生长代谢影响因素有很多,本试验主要对温度、pH、培养基的量以及接种量进行研究,同时也研究了不同氮源及能源条件对菌生长的影响,确定出氧化亚铁硫杆菌的最佳培养条件为温度28℃,pH=2.0,装液量为100mL(250mL锥形瓶),接种量为10%,最容易利用的能源物质是FeSO4,氮源是硫酸铵。     

Bioleaching of copper ore flotation concentrates

The bioleaching of flotation concentrate is a new method for copper recovery that could form the basis of an economic and environmentally friendly process. The main objective of this work was to evaluate a bioleaching process from the treatment of two concentrates, (i) a copper gold bearing concentrate and (ii) an ordinary copper flotation concentrate, using mesophilic bacteria. The special gold-bearing copper flotation concentrate was obtained from the Polkowice Mine. The second material was an ordinary copper flotation concentrate purchased from the Lubin Mine. Bioleaching experiments were carried out in 250 ml Erlenmayer flasks and a rotating bioreactor (biorotor). The most important operating parameters were copper dissolution (%) and surface area. A culture of Thiobacillus ferrooxidans was used for the bioleaching tests. The bioleaching maximum was obtained at both 12% and 15% of the solid. The effect of pyrite addition on the kinetics of copper concentrate bioleaching was also investigated. It was established that 3% of pyrite causes an increase in the bioleaching process. In the case of ordinary flotation concentrate bioleaching, 65% of the recovery was obtained at the initial stage (48 h). In the second stage, the copper recovery slowly increased and after 312 h 86% of the copper recovery was obtained. On the other hand, the surface area of copper concentrate initially increased (at 24 h it was 8.67 m²/g) and then slightly decreased in the second stage.     

氧化亚铁硫杆菌筛选及基质中Fe2+氧化研究

用液体、固体培养基交替培养的方法从某矿酸性矿坑水中得到一株氧化亚铁硫杆菌,研究了不同初始Fe2 浓度对该菌氧化速率的影响,同时还研究了初始pH值与初始Fe2 浓度对培养过程中沉淀产生的影响。结果表明:初始Fe2 的浓度为9.05 g/L,pH值为2.0左右是减少沉淀产生和发挥细菌氧化活性的最佳条件。     

The effect of redox control on the continuous bioleaching of chalcopyrite concentrate

A continuous bioleaching process was developed for the dissolution of chalcopyrite concentrate with electrochemically redox control. Therefore, using a flotation concentrate containing 46% chalcopyrite and 23% pyrite, bioleaching tests were carried out at 47 °C with 15% pulp density under controlled and uncontrolled redox conditions. To increase the copper recovery in contrast to the conventional bioleaching (∼39.62%), the effect of redox potential on the chalcopyrite bioleaching was investigated by electrochemically controlled bioleaching. The results showed that by controlling the redox potential, faster copper leach kinetics could be achieved. At last, reducing the redox potential from high levels to optimum window (420–440 mV SCE) caused an increase in copper recovery from around 39% to higher than 69% (over 25 g/L Cu²⁺).     

氧化亚铁硫杆菌的筛选及其特性研究

从广东云浮一硫铁矿的酸性废水中分离出一株氧化亚铁硫杆菌,对其菌落形态和细胞形态进行了初步的探讨,研究了温度、初始pH、Fe2+初始浓度、接种量对细菌氧化Fe2+的影响。试验结果表明,该菌在pH=2 0、温度30～35℃活性最强,同时加大接种量也可以缩短细菌的迟缓期,培养基中过高的Fe2+浓度对该菌生长起抑制作用。     

钼尾矿中钼、铜和铁的生物浸出实验研究

使用浸矿微生物对钼尾矿进行生物浸出,在钼尾矿质量10 g、矿浆浓度10%(w/v)、微生物加入量10 mL(微生物初始浓度2×10⁷个/L)、浸出温度28 ℃条件下,经过21 d生物浸矿,钼尾矿中的Mo、Cu和Fe浸出率分别达到82.87%、83.73%和88.78%,钼尾矿中的重金属含量大大降低。物相分析结果表明,浸矿微生物对尾矿中的辉钼矿、黄铁矿和黄铜矿的氧化作用,以及铁离子对辉钼矿的化学浸出作用,实现了尾矿中Mo、Cu和Fe的有效浸出。     

The effect of As(III) and As(V) on the batch bioleaching of a pyrite-arsenopyrite concentrate

The bioleaching of arsenical gold-bearing sulphide ores and concentrates solubilises iron, arsenic and sulphur. Previous work has shown that high concentrations of iron and arsenic in solution inhibit bacterial growth, with As(III) reported to inhibit bacteria to a greater degree than As(V).Batch bioleaching experiments were carried out over periods of one month. Varying quantities of either 0.020–0.040 M As(III) or 0.107–0.220 M As(V), were added to a slurry, consisting of a pyrite-arsenopyrite concentrate (20% solids (m.v⁻¹)) in a nutrient solution. The slurry was inoculated with a culture, consisting primarily of Leptospirillum ferrooxidans and Thiobacillus thiooxidans. The culture was obtained from a continuous bioleaching mini-plant treating the same concentrate. The results obtained were compared with those of a culture to which no arsenic was added. The effect of the added arsenic was determined by monitoring three parameters: the oxygen utilisation rate, r_O2, of the culture, the rate at which the arsenic in the concentrate was solubilised and the speciation of the dissolved arsenic.The results suggest that the nature of the As(III) and As(V) toxicity is different. The addition of the culture to a slurry containing As(III) resulted in a reduced rate of bacterial oxidation. However, the addition of the culture to a slurry containing As(V) resulted in both a lag phase and a reduced rate of bacterial oxidation. At sufficiently high dosages of As(III) and As(V) the maximum oxygen utilisation rate, r_O2^max, of the culture was also affected. The results indicate that As(V) toxicity, and the relative toxicity of As(III) and As(V) to a mixed culture, appear to be affected by the availability of an energy source. Hence the toxicity of As(III) is not necessarily in the region of three times that of As(V). Furthermore, the results suggest that the mechanism of arsenic resistance may be attributed to the Pst⁺ Pit⁻ mutations and an energy dependent efflux pump.     

Engineered strains enhance gold biorecovery from electronic scrap

Gold bioleaching from electronic scrap materials (ESM) was examined using the bacterium Chromobacterium violaceum which produces and detoxifies cyanide, one of the few lixiviants capable of leaching gold. Gold recovery by the wild-type C. violaceum and two genetically engineered strains (pBAD and pTAC) with an additional cyanide-producing operon were investigated and compared. The ESM was pretreated to remove metals competing for metal cyanide complexation with gold. The effect of pulp density on leaching performance by the various strains was also investigated. The pBAD strain produced the highest cyanide concentration, and achieved the highest gold recovery of 30% at 0.5% w/v pulp density, compared to 11% recovery by the wild-type bacteria. Our results demonstrated the application of lixiviant metabolic engineering in the construction of enhanced bioleaching microbes for the bioleaching of precious metals from electronic waste.     

Strategies for efficient start-up of continuous biooxidation process for refractory gold ores

Strategies for efficient start-up of a continuous process for biooxidation of refractory gold ore and concentrate obtained from Hutti Gold Mines Limited (HGML), India are discussed in this work. The biooxidation of the concentrate at high pulp density (10%) with wild strain of Thiobacillus ferrooxidans isolated from HGML mines is characterized by significant lag phase (20 days) and incomplete oxidation (35%) even after prolonged operation (60 days). Two strategies, biooxidation with concentrate adapted cells and a step leaching strategy, in which the pulp density is progressively increased from 2% to 10% were considered and the latter resulted in efficient biooxidation of concentrate. Conversion of such a process from batch to continuous operation is shown to result in complete biooxidation of the concentrate and gold extraction efficiency in excess of 90%.     

铜萃取界面乳化液中浸矿微生物的多样性

界面乳化是溶剂萃取过程中难以避免的现象,显微观察发现在铜萃取界面乳化液中存在形貌复杂多样的微生物。利用16s rRNA基因测序技术对铜萃取界面乳化液中微生物种群结构进行分析,结果发现包括Leptospirillum sp,Acidithiobacillus ferrooxidans,Metallibacterium sp,Staphylococcus sp在内的7类细菌,其中优势菌种为Leptospirillum sp.E4-L9和Acidithiobacillus ferrooxidans ATCC 23270,两者在乳化液细菌中分别占到40.48%和38.1%。利用Fe2+和硫作为能源对界面乳化液中的微生物进行分选,进一步分析种群结构。铜萃取界面乳化对浸矿细菌有截留作用,从而会降低生物浸矿效率。