Cu2+、Fe2+和Fe3+对中等嗜热混合菌浸出黄铜矿的影响

在50℃、pH 1.6的条件下,研究了Fe2+、Fe3+和Cu2+对中等嗜热混合菌浸出黄铜矿的影响.结果表明:添加低质量浓度Fe2+时,在浸出前期能够促进黄铜矿的浸出;而添加较高质量浓度Fe2+时,铜的浸出率反而降低;当添加不同质量浓度Fe3+时,由于形成黄钾铁矾而导致总铁质量浓度降低,但铜的浸出率并没有明显变化;添加...     

不同碳材料辅助下混合中度嗜热微生物浸出黄铜矿的比较研究（英文）

采用混合中度嗜热微生物研究4种碳材料(人造石墨、炭黑、活性炭和碳纳米管)对黄铜矿浸出的催化作用。结果表明,添加人造石墨和活性炭能使溶液pH值降低,氧化还原电位维持在合适的范围,使浸出液中总铁、三价铁浓度和矿渣表面吸附微生物的数量增加,最终提高黄铜矿中铜的浸出率;而添加炭黑和碳纳米管能抑制浸矿微生物的生长,最终导致浸出效率降低。X射线衍射分析表明,在添加人造石墨和活性炭实验组中,黄钾铁矾和硫膜是钝化层的主要成分,但钝化层的形成不会影响黄铜矿的进一步分解。此外,人造石墨和活性炭的添加使浸出体系中游离微生物和吸附微生物的群落结构发生改变。在黄铜矿浸出末期,硫氧化茵A.caldus S1(丰度为93%～98%)成为优势菌种,而铁氧化菌L.ferriphilum YSK所占比例仅为1%～2%。     

混合高温菌浸出黄铜矿及浸出过程中微生物群落的演替

研究3株极端嗜热古菌(金属硫叶菌,Sulfolobus metallicus JCM 9184;瑟杜生金属球菌,Metallosphaera sedula JCM 9185和万座酸菌,Acidianus manzaensis YN25)在不同起始pH值和不同温度条件下对黄铜矿的混合浸出,并对浸矿过程中混合菌群落的动态演替进行分析.结果表明:在起始pH 1.5时的铜浸出率明显高于在起始pH 2.5时的铜浸出率,而65 ℃条件下的铜浸出率高于75 ℃时的铜浸出率.利用限制性长度多态性(RFLP)分析65 ℃、起始pH 1.5条件下的微生物群落演替,结果显示:在黄铜矿的浸出前期Sulfolobus metallicus是占据优势的菌种,而到后期Acidianus manzaensis的比例则会上升,并最后取代Sulfolobus metallicus成为优势种.     

黄铁矿对砷黄铁矿生物浸出的影响

为探明黄铁矿在砷黄铁矿生物浸出过程中的作用与影响,选择纯黄铁矿和砷黄铁矿组成的矿浆浸出体系,考察黄铁矿和砷黄铁矿质量比以及黄铁矿粒度对体系中砷的浸出率以及砷的氧化状态的影响。结果表明：砷的浸出率随黄铁矿与砷黄铁矿质量比的增加而升高,随黄铁矿粒度的增加而减少。当黄铁矿的粒度小于74μm、黄铁矿与砷黄铁矿质量比为10：2时,砷的最高浸出率为97.7%,比不添加黄铁矿时砷的浸出率提高了约43.18%。且黄铁矿可以加速As(Ⅲ)转化为As(Ⅴ),降低矿浆对细菌的毒害,使生物浸出体系细菌密度提高、pH下降、氧化还原电位φh升高并与砷黄铁矿形成原电池效应,从而促进砷黄铁矿的浸出。     

过程pH刺激对游离和吸附菌协同浸出黄铜矿的影响（英文）

为了研究过程pH刺激对中度嗜热菌浸出黄铜矿的影响,测定浸出过程中铜的浸出率以及游离和吸附菌的微生物群落结构动态变化。结果表明,将浸出第14天浸出过程的pH分别调节至1.0及3.0时,游离菌和吸附菌的生长均出现一个适应期。同时,未调节pH的对照组铜的浸出率为87.5%;而调节过程pH至1.0和3.0时,铜的浸出率分别下降至86.9%和64.0%。实时定量PCR分析表明,pH刺激对吸附菌的影响比对游离菌的影响小,说明吸附菌比游离菌对过程pH刺激具有更强的抗性。此外,调节过程pH至3.0显著破坏了游离菌和吸附菌的群落结构,浸出体系无法恢复至正常状态。     

中度嗜热微生物浸出复杂多金属铜精矿的优化(英文)

研究了中度嗜热微生物浸出复杂多金属铜矿过程中初始pH、温度、装液量、转速、原电池效应(黄铁矿比例)和矿浆浓度的影响。结果表明,初始pH为1.5的铜浸出率分别是初始pH为1.0和2.0的实验组浸出率的1.5倍和1.4倍。当温度为45°C时铜的浸出率比温度为50°C时的高出1236.8%。随着转速的升高和装液量的降低,铜的浸出率明显提高。当黄铁矿的比例增大时,铜的浸出率也逐渐提高,但是当黄铁矿比例高于20.0%后,铜浸出率不再增加。温度和pH及温度和黄铁矿比例之间存在显著的交互作用。     

磷灰石在微生物浸铜体系的溶出特性及对浸铜效率的影响

为了探明磷灰石在微生物浸出黄铜矿体系中的溶出特性及其对黄铜矿浸出的影响,选择粒径小于43μm的磷灰石与粒径小于74μm的黄铜矿以及At.f菌组成矿浆浸出体系,考察不同At.f菌接种量对于磷灰石溶出速率的影响及对黄铜矿浸出效果的影响。结果表明:浸出体系中含低浓度PO3-4可以提高铜的浸出效率;当At.f菌接种量为5%时,微生物浸出体系中磷灰石溶出的PO3-4浓度最小,为0.62 mg/L,此时黄铜矿的最终浸出率最高,达到57.4%,比PO3-4溶液浓度最高时体系的铜浸出率提高近30%。通过对微生物浸出前、后的浸渣进行扫描电镜、能谱分析和XRD分析发现,浸出后磷灰石表面浸蚀不明显,而黄铜矿表面浸蚀明显,同时浸渣中有新物质铵黄铁矾生成;磷灰石对于新生成的沉淀有一定的吸附作用,而且溶出较低浓度的PO3-4体系能提高黄铜矿的浸出。     

活性炭对含钴矿物生物浸出的催化作用

研究活性炭对含钴矿物摇瓶生物浸出的影响。结果表明:在浸出过程中,由于原电池效应,添加活性炭加速硫铜钴矿的氧化溶解,钴的浸出率也随之提高。添加1.0 g/L活性炭,在矿浆浓度为10%、浸出温度为45℃、转速为180 r/min的条件下,钴浸出率提高22.06%,铜浸出率提高15.43%。粒状活性炭与粉末状活性炭具有相同的催化效果,硫铜钴矿的生物浸出不受活性炭形状影响,生物浸出过程中可以用活性炭颗粒代替活性炭粉末。pH值对活性炭对钴离子的吸附有控制作用,随着pH值降低,活性炭对钴离子的吸附量减小,浸出条件下金属离子的损失可忽略。     

微生物浸出Pb-Zn-Sn黄铜矿及其生物群落的演替分析

研究了Pb-Zn-Sn黄铜矿精矿在混合中度嗜热微生物槽浸过程中的细菌群落结构变化,并监测浸出体系中金属离子浓度、溶液电位、溶液pH值变化,通过聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）技术分析微生物群落的结构变化。结果表明,最终铜浸出率高达85.6%,在浸出前期,Acidithiobacillus caldus为优势群落,从第18天开始到浸出结束,Sulfobacillus thermosulfidooxidans为优势群落,但Leptospirillum ferriphilum丰度变化较小。试验结果表明,适当较高的溶液电位和合适的铁离子浓度对黄铜矿精矿的生物浸出作用很关键。     

初始pH对极端嗜热菌万座嗜酸两面菌作用下黄铜矿氧化溶解的影响(英文)

采用生物浸出和循环伏安试验研究初始pH对黄铜矿在65℃条件下氧化溶解的影响,分别采用XRD和拉曼光谱分析黄铜矿生物浸出过程中和电极表面形成的氧化产物。化学浸出结果表明:黄铜矿溶解速率随着初始pH的减小而增大,然而初始pH对黄铜矿生物浸出的影响却正好相反。当初始pH为1.0时,万座嗜酸两面菌的加入几乎没有促进黄铜矿的溶解,这主要是由于高酸度严重抑制了万座嗜酸两面菌的生长。电解液中存在或不存在万座嗜酸两面菌时黄铜矿的阳极氧化电流都随着初始pH的增大而增大,同时在黄铜矿电极表面检测到了单质硫和铜蓝。结果表明,在化学浸出过程中黄铜矿是在质子作用和氧化作用下溶解的,黄铜矿氧化生成了铜蓝和单质硫。     

Bioleaching of chalcopyrite by pure and mixed culture

The bioleaching of chalcopyrite in shake flasks was investigated by using pure Acidithiobacillusferrooxidans and mixed culture isolated from the acid mine drainage in Yushui and Dabaoshan Copper Mine in China, marked as YS and DB, respectively. The mixed culture consisted mainly of Acidithiobacillus fOrrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum spp. （Leptospirillum ferriphilum and Leptospirillum ferrooxians）. The results show that the mixed culture is more efficient than the pure Acidithiobacillus ferrooxidans because of the presence of the sulfur-oxidizing cultures that positively increase the dissolution rate and the recovery of copper from chalcopyrite. The pH value decreases with the decrease of chalcopyrite leaching rate, because of the formation ofjarosite as a passivation layer on the mineral surface during bioleaching. In the bioleaching using the mixed culture, low pH is got from the sulfur oxidizing inhibiting, the formation ofjarosite. The copper extraction reaches 46.27% in mixed culture and 30.37% in pure Acidithiobacillusferrooxidans after leaching for 75 d.     

Sustainable copper extraction from mixed chalcopyrite–chalcocite using biomass

This paper elaborated on the sustainability of the copper extraction process. In fact, an alternative copper extraction route from mixed sulphide ores, chalcopyrite and chalcocite using mesophilic biomass consortium at 33.3 °C and ferric leaching process were attempted. Bioleaching experiments were settled with a fraction size of −75+53 µm. Bacteria were used as the catalyst. A copper yield of 65.50% was obtained. On the other hand, in ferric leaching process, with a fraction size of −53+38 µm, when the temperature was increased to 70 °C, the copper leaching rate increased to 78.52%. Thus, comparatively, the mesophilic bioleaching process showed a more obvious advantage in copper extraction than leaching process with a high temperature. However, it has been resolved from the characterization performed using SEM−EDS, FTIR and XRD observations coupled with different thermodynamic approaches that, the indirect mechanism is the main leaching mechanism, with three transitory mechanisms (polysulphide, thiosulphate and elemental sulphur mechanisms) for the mixed chalcopyrite−chalcocite ore. Meanwhile, the speciation turns into Cu₂S−CuS−Cu₅FeS₄−Cu₂S before turning into CuSO₄. While ferrous oxidation and the formation of ferric sulphate occur, and there is a formation of strong acid as bacteria digest sulphide minerals into copper sulphate at low temperature, which is why this copper production scenario requires a redox potential more than 550 mV at room temperature for high copper leaching rate.     

Study on bioleaching of primary chalcopyrite ore with thermoacidophilic archae

A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.     

STUDY ON BIOLEACHING OF PRIMARY CHALCOPYRITE ORE WITH THERMOACIDOPHLIC ARCHAE

A high temperature-tolerating thermoacidophilic archae (TA) was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of 1.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcopyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans (Tf) leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching (196 days), that is,a two-month (56 days) Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/(L· d), while for the control experiments, it was as low as 78mg/(L· d) for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf. Therefore, it is suggested that the two-phase leaching process be applied to for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.     

Feasibility study on heap bioleaching of chalcopyrite

Bioleaching of chalcopyrite often encountered the formation of passivation layer, which inhibited the leaching process and resulted in a low leaching rate. This inhibitory effect can be eliminated by thermophilic biole- aching. The industrial test of BioCOP technology based on thermophiles was successfully completed, which confirmed the feasibility of chalcopyrite bioleaching. However, industrial leaching rate of chalcopyrite heap bioleaching is lower. This paper described the development status and industrial test of chalcopyrite heap bioleaching technology. The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed. The strategies for successful chalcopyrite heap bioleaching were proposed.     

生物浸出过程中黄铜矿钝化的控制方法(英文)

在细菌浸出黄铜矿的过程中,黄铜矿表面钝化是普遍现象,成为生物浸铜技术的瓶颈问题。对比研究了普通浸出与强化浸出(加入玻璃圆珠)对铜浸出的影响。结果表明,玻璃圆珠的加入改善了浸出条件,削弱了黄铜矿的钝化效应,使黄铜矿的Cu浸出率从50%提升至 89.8%。扫描电镜(SEM)和X射线衍射(XRD)分析发现,添加玻璃圆珠的黄铜矿表面没有黄钾铁矾沉淀,钝化作用不明显;而不加玻璃圆珠的黄铜矿表面附着厚厚的结构致密的黄钾铁矾,钝化严重,从而阻碍了黄铜矿的溶解和浸出。     

Comparison on the leaching kinetics of chalcocite and pyrite with or without bacteria

The acid leaching, ferric leaching, and bioleaching of chalcocite and pyrite minerals were conducted in two sets of 3L stirred reactors. The dissolution rates of copper and iron were correlated with leaching conditions. In the acid leaching process, the dissolution rate of chalcocite was around 40wt.% while that of pyrite was less than 4%. In the ferric leaching process with high ferric concentration, only 10 wt.% of iron in pyrite was leached out at the same retention time though the copper recovery over 60 wt.% in chalcocite. For the bioleaching process, the chalcocite leaching rate was highly increased, nearly 90 wt.% of copper was leached out, and the iron dissolution of pyrite exceeded 70 wt.%. For the two minerals, the bioleaching shows the highest leaching rate compared with the acid leaching or ferric leaching. In uncontrolled bioleaching process, pyrite could be dissolved effectively. The experimental data were fitted to the shrinking core and particle model. The results show that in all the leaching tests, the chalcocite leaching was mainly controlled by diffusion, while for the pyrite leaching, chemical reaction is the main rate-determining step.     

Mechanism of silver-influenced bacterial leaching of chalcopyrite, pyrite and a copper ore

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Relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleaching by mixed thermophilic Archaea culture at 65 °C

The relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleaching by mixed thermophilic Archaea culture (Acidianus brierleyi, Metallosphaera sedula, Acidianus manzaensis and Sulfolobus metallicus) at 65 °C was studied. Leaching experiments showed that the addition of activated carbon could significantly promote the dissolution of chalcopyrite for both bioleaching and chemical leaching. The results of synchrotron-based X-ray diffraction, iron L-edge and sulfur K-edge X-ray absorption near edge structure spectroscopy indicated that activated carbon could change the transition path of electrons through galvanic interactions to form more readily dissolved secondary mineral chalcocite at a low redox potential (<400 mV) and then enhanced the copper dissolution. Jarosite accumulated immediately in the initial stage of bioleaching with activated carbon but copper dissolution was not hindered. However, much jarosite precipitated on the surface of chalcopyrite in the late stage of bioleaching, which might account for the decrease of copper dissolution rate. More elemental sulfur (S⁰) was also detected with additional activated carbon but the mixed thermophilic Archaea culture had a great sulfur oxidation activity, thus S⁰ was eliminated and seemed to have no significant influence on the dissolution of chalcopyrite.     

Marmatite bioleaching with moderately thermoacidophilic bacterial strain and mineral analyses of solid residues

The bioleaching of a marmatite flotation concentrate with a moderately thermoacidophilic iron-oxidizing bacterial strain （MLY） is influenced significantly by temperature, pH, particle size, pulp density of ores and bacterial strains. Under such leaching conditions as the initial pH value of 1.5, temperature of 50℃, pulp density of 5%, particle size less than 35.5μm （over 90%） and inoculating the adapted strains of MLY, the leached Zn is over 95% after 10 d of bioleaching. SEM observations show the cell attachment and the surface features of solid residues under different leaching conditions. XRD and EDX analyses show that a mass of elemental sulfur form during the bioleaching process. The technological feasibility of a microbiological process using MLY for extracting zinc from the marmatite concentrate is demonstrated.