【作者】 张在海；

【导师】 王淀佐； 胡岳华； 邱冠周；

【作者基本信息】 中南大学 ， 矿物加工工程， 2002， 博士

【摘要】 一、细菌对铜硫化矿的作用及其改善 1．铜硫化矿的细菌浸出机制目前有二种看法。 一是认为细菌直接对铜硫化矿物进行氧化浸出，称为直接作用，如黄铜矿细菌浸出反应为：二是认为细菌把硫化矿物中释放出来的亚铁和元素硫分别氧化成高铁和硫酸，后二者作为浸出剂对铜硫化矿进行浸出，称为间接作用，则黄铜矿浸出反应为： 2．本文研究了从大宝山铜矿的细菌浸出原液中分离出来的两种主要浸出菌种——氧化亚铁硫杆菌（Thiobacillus ferrooxidans简称D-T．f）和氧化硫硫杆菌（Thiobacillus thiooxidans简称D-T．t）氧化生理特性及其浸出，表明D-T．f菌具有较强的催化氧化Fe²⁺、S^2-的活性，而几乎没有催化氧化S⁰的活性；D-T．t菌只发现具有较强的催化氧化S⁰的活性；D-T．f菌具有较强的氧化浸出黄铜矿精矿的能力，而D-T．f菌氧化浸出黄铜矿精矿的能力较弱。 3．分别用Fe²⁺、S⁰、CuS和CuFeS₂为能源对原菌进行富集培养，发现用CuS富集的菌种浸矿能力最强，Fe²⁺富集菌和CuFeS₂培养菌次之，S⁰富集菌最差；用分离出的D-T．f S^2-氧化缺陷型菌株进行浸出，发现它比具有这种氧化能力的正常菌株的浸出效果差得多。D-T．t菌和D-T．f菌同时浸出黄铜矿精矿，在通常情况下D-T．f菌并不促进D-T．f菌对黄铜矿的浸出，而只有当外加一定量的元素硫时，方起一定的促进浸出作用。 4．研究结果显示浸矿细菌的氧化生理特性与浸出效果有密切关系，黄铜矿的细菌浸出效果同细菌的S^2-氧化活性关系最大；并根据几种主要浸矿细菌的氧化生理特性，预示了它们在浸矿体系中所起的浸出作用大小和机制。 二、浸出环境中的离子或物质对细菌氧化及对铜硫化矿浸出的影响 1．研究了浸出环境中Ag⁺、Cu²⁺、S⁰和pH等离子或物质对细菌氧化Fe²⁺的影响，结果是：在Ag⁺浸出体系中，Ag⁺对细菌氧化Fe_（aq）²⁺具有抑制作用；Cu²⁺有抗Ag⁺抑制的作用；S⁰的影响与S⁰／Fe²⁺_（aq）的比值有关；pH有一定的适合范围。博士学位论文铜硫化矿生物浸出高效菌种选育及浸出机理 2.研究了上述离子或物质对细菌浸出黄铜矿精矿的影响，结果是体系中有Ag+或无Ag十时，浸出行为刚好相反:前者铜浸出率高、溶液铁少且浓度较稳定、pH值较高且稳定、游离细菌浓度较高、浸渣中发现有s0生成;后者铜浸出率低、溶液铁不断增多、pH不断降低、游离细菌数量较少、浸渣中未发现s0。同时，用预先Ag十培养过的D一Tf菌浸矿效果最好，它对浸出溶液中的亚铁氧化也最慢;在有Ag十存在的条件下，加入D一介菌能明显促进D一Tf菌的浸出作用。 三、复合矿粒间的生物电化学作用 大宝山铜矿石中含有锌硫化物。用闪锌矿与硫铁矿紧密并存的硫化矿进行了矿物表面细菌浸出行为的研究，当用D一T.f菌浸出时，锌被大量浸出，细菌吸附于黄铁矿表面;当用D一关t菌浸出时，锌浸出较少，而且未观察到吸附的细菌。这些结果提示了一种新的生物电化学机制:D一大f菌是吸附在高电位的金属硫化物上，从中获得从低电位转移而来的电子，从而促进了矿物的电化学腐蚀。此种情况下，它与D一大t菌的浸出差异，同样是与它们的氧化生理特性的不同有关。 四、浸矿细菌培养工艺参数及相关技术 1.对D一厂f菌和D一大t菌在液体或固体培养基上的生长特性进行了研究，发现D一入f菌能在Fe2+为能源的固体培养基上较好地形成菌落，而在以Na石ZQ、为能源的固体培养基上不能形成菌落，在这两种能源混和的复合固体培养基上不长菌落，在合成的硫化铜固体培养基上菌落针尖大小。D一大t菌在FeZ十为能源的固体培养基上不生长，在NaZsZo。为能源的固体培养基上生长良好，在上述复合培养基中有一部分生长。 D一大厂菌不能在NaZS办，为能源的固体培养基上生长和D一T.t菌能在NaZS从为能源的固体培养基上生长良好，这两个点分别不同于已报导的从其它地点分离出来的相应菌种。 2.总结得到了D一入f菌生长和培养的一些参数:D一关厂菌在分批培养中生长对数期长，约占亚铁完全氧化时间的90%，生长稳定期很短，约占6一8%，其比生长速率平均为o.106h一’，传代时间平均为6.54h，生物干重量大致为0.03219/L;其固体培养基最佳配方为:FeSO‘:·SH:0 22.29/L、（N卜11）250139/L、K步IPO:0.59/L、MgSOJ 0.59/L、Ca（NO3）2 0.019/L、pH3.O、琼脂159/L。研究出D一大t菌ZZH新配方，使它的固体培养生长良好。 五、堆浸现场菌种实际分布及高效T.f菌培育方法 1.对成熟期低品位硫化矿细菌堆浸场的菌种资源进行了调查，表明30博七学位论文铜硫化矿生物浸出高效菌种选育及浸出机理℃左右的关f菌株群起主要作用，没有发现中等高温菌种和高温菌种;细菌亚铁氧化活性不断降低影响了细菌复制增殖速度，使浸出细菌总数量减少，提出有必要增强细菌的Fe2+氧化活性。 2.鉴于以52一为能源的固体培养技术尚未成熟，只对细菌的FeZ+氧化活性进行了菌种驯化、筛选和诱变研究，发现D一关f菌的紫外诱变剂量以杀伤率为20一30%最好;正突变菌能在一定程度上提高含铜硫化矿的铜浸出率。 3.复更多还原

【Abstract】 The bioleaching of copper sulfide and its improving1. Two mechanism of bacterial leaching for copper sulfide minerals have ever been proposed, when copper sulfide minerals are leached directly by bacteria, it is the direct mechanism, such as:CuFeS2+4O2 bacteria CuSO4+FeSO4The second mechanism is indirect mechanism in which the ferrous ion and elemental sulfur releasing from sulfides are oxidized into ferric ion and sulfuric acid individually by bacteria, the copper sulfide minerals are dissolved as the following reaction:4FeSO4+2H2SO4+O2 bacteria 2Fe2(SO4)+2H2O2S0+2H2O+3O2 bacteria 2H2SO4 CuFeS2+2Fe2(SO4) CuSO4+5FeSO4+2S02. In the present work, the two bacterial species in the original solution from the Da Bao Mountain Copper Mine were isolated - Thiobacillus ferrooxidans(D-T.f) and Thiobacillus thiooxidans(D-T.t). The physiological characters for oxidation and leaching of these two bacteria were studied. It was demonstrated that D-T.f is characterized by higher activities oxidizing ferrous ion and reduced sulfur, with no activity oxidizing elemental sulfur; The D-T.t is characterized by higher activities oxidizing elemental sulfur, without the activity oxidizing ferrous ion and reduced sulfur. The D-T.f has good leaching efficiency on chalcopyrite concentrate. The D-T.t can not leach the chalcopyrite concentrate.3. The original bacteria were enriched with ferrous ion elemental sulfur reduced sulfur and chalcopyrite as energy resource, respectively. The results showed that the bacteria enriched by reduced sulfur exhibited most effective leaching chalcopyrite concentrate, then the bacteria enriched by ferrous ion or chalcopyrite. The bacteria enriched by elemental sulfur showed poor leaching efficiency. The results further showed that when the bacteria without the activity oxidizing the reduced sulfur were used, Its leaching efficiency is much worse than normal D-T.f. When the D-T.f and D-T.t were mixed to leach the chalcopyrite concentrate, it was demonstrated that the leaching of D-T.f is not accelerated byadding T.t at common circumstance, while when the elemental sulfur is added, the D-T.t will accelerate the leaching rate.4. Tt was revealed from the results that the efficiency of bacterial leaching of chalcopyrite is closely related to the physiological characters of oxidation of these bacteria reported. Discuss on the influence of ions or other substrate on bacterial oxidation and leaching of copper sulfide1. The influence of silver ion, cupric ion, elemental sulfur and pH on the bacterial oxidation for ferrous ion have been studied. It has been shown that silver ion has inhibition on bacterial oxidation of ferrous ion; cupric ion has anti-inhibition of silver ion; the influence of elemental sulfur is related to the ration of elemental sulfur to ferrous ion; pH has a certain suitable range.2. The bacterial leaching of chalcopyrite is characterized by much higher leaching rate of copper , much less and stable in dissolved total Fe in solution higher and stable pH, higher concentration of free bacteria, elemental sulfur occuring in the residue in the presence of silver ion. In absence of silver ion the leaching showed much lower leaching rate of copper, increasing dissolved total Fe in the solution, decreasing pH, less concentration of free bacteria, no elemental sulfur occurring in the residue. The best efficiency has been obtained using the D-T.f cultured with silver ion forehand, which has also slower oxidizing ability to the ferrous ion in the leaching solution. The acceleration of the bacterial leaching of chalcopyrite was made by adding D-T.t into the leaching solution with D-T.f and silver ion. Discuss on bio-electrochemistry between different mineral particles The copper sulfide minerals coming from Da Bao Mountain contains zincsulfide. The bacterial leaching behavior of the zinc sulfide minerals closely disseminated with pyrite has been studied. It showed that a lot of zinc ion from zinc sulfide is leached by D-T.f,更多还原