不同类型黄铜矿的生物浸出研究

研究了两种不同类型(黄铁矿型,斑岩型)黄铜矿生物浸出的差异.实验结果表明:两类黄铜矿生物浸出差别很大,48 d后黄铁矿型黄铜矿浸出率为46.96%,斑岩型黄铜矿浸出率为14.5%.对Fe2+、矿物表面Cu2p谱图和矿床特征的分析发现:适量的Fe2+能促进黄铜矿的浸出,但最佳用量不一样;浸渣表面产物不同,斑岩型黄铜矿表面出现富铜层,阻碍了浸出继续进行;与原矿相比,铜结合能都降低,符合Hiroyoshi等提出黄铜矿浸出的两步溶解模型;两类黄铜矿生物浸出的差异是由成矿岩体、围岩、伴生矿物和元素、成矿温度和压力等因素综合决定的.     

黄铁矿促进黄铜矿微生物浸出影响因素

采用摇瓶实验,以氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,At.f)浸出黄铁矿--黄铜矿,重点研究了基础培养基、矿物配比和粒度组成等因素的影响.黄铁矿能促进黄铜矿的微生物浸出,以采用无Fe 9K培养基效果较好,它对应铜浸出率是9K培养基的1.68倍;采用宽粒级矿物时铜浸出效果较好,且铜浸出率与黄铁矿和黄铜矿的质量比有关,当质量比为2∶2时铜浸出率最高可达45.58%;黄铁矿含量大小是影响铜浸出率高低的实质,当质量比小于等于5∶2时以At.f菌的氧化作用为主,当质量比为10∶2时以硫化矿间的原电池效应为主.浸渣的X射线衍射分析表明,采用无Fe 9K培养基时浸渣中生成的钝化物黄钾铁矾较少,故黄铁矿可以很好地替代9K培养基中的FeSO4,并能与黄铜矿形成原电池效应,从而促进铜的浸出.     

Acidithiobacillus ferrooxidans对黄铜矿和镍黄铁矿的浸出

以黄铜矿和镍黄铁矿为研究对象,初步探讨了Acidithiobacillus ferrooxidans对黄铜矿和镍黄铁矿的浸出.结果表明:有细菌参与下,黄铜矿的浸出率是无菌体系浸出率的2.41倍;镍黄铁矿的浸出率是无菌体系浸出率的1.91倍,细菌在矿物的浸出过程中起到了很好的促进作用.浸出过程中会有黄色的黄钾铁矾(K[Fe3(SO4)2(OH)6])沉淀产生,黄钾铁矾附着在矿体表面,产生"钝化现象",严重阻碍矿物的氧化.     

氰化尾渣浮选回收过程中黄铜矿的界面特性研究

氰化尾渣是氰化提金过程中产生的固体废弃物,同时也是高价值的二次资源,含有大量的铜、铅、锌等有价元素。由于氰化过程长时间的充气搅拌,氰化尾渣的矿物界面发生严重的改性,但是关于这方面的研究较少。本文针对某高铜铅氰化尾渣浮选过程中存在铜铅难分离及铜回收率低等问题开展黄铜矿界面性质研究,采用的研究方法包括粒度分析仪、XRD分析、SEM–EDS微界面分析、FTIR分析、界面洗脱及浮选实验等。实验结果表明部分黄铜矿表面致密包裹一层细粒的方铅矿,导致黄铜矿表现为类似于方铅矿的浮选特性,导致这种现象的原因是黄铜矿表面被非极性油污染。不能被浮选回收的黄铜矿表面包裹一层铁矾类似物,导致黄铜矿表面被钝化而不利于药剂的吸附。通过研究可知氰化尾渣中黄铜矿界面容易被杂质污染及氧化层包裹,导致其难于被浮选回收。     

氧化亚铁硫杆菌对黄铜矿表面性质及其浸出的影响

通过测定吸附量、Zeta电位和接触角,并通过对原子力显微镜表面进行表征及摇瓶浸出试验考察不同能源(Fe2+、单质硫和黄铜矿)培养的氧化亚铁硫杆菌A.ferrooxidans对黄铜矿表面性质的影响及其与黄铜矿浸出的关系。研究结果表明:不同能源培养的A.ferrooxidans菌对黄铜矿表面性质的影响规律相似;A.ferrooxidans菌均能快速吸附在黄铜矿表面,而矿驯化的A.ferrooxidans菌在矿表面的附着能力更强;细菌的吸附使黄铜矿的等电点朝细菌的等电点方向偏移,且由于在黄铜矿表面生成了硫膜和不稳定铜硫化物使得黄铜矿表面接触角增大,疏水性增强;在浸矿初期,细菌与黄铜矿作用以直接作用机理为主。     

石英对微生物浸出黄铜矿的作用

为探明石英在微生物浸出铜过程中的作用与影响,选择粒度<43μm的石英,与黄铜矿和黄铁矿形成矿浆浸出体系,考察了石英质量浓度对黄铜矿浸出效果的影响.结果表明:适量的石英,其粒度越细越能促进黄铜矿的浸出.当石英质量浓度为50g·L-1、粒度<43μm时,黄铜矿的浸出率最高可达54·09%,比不添加石英的浸出率提高了近20%;通过对微生物浸出过程的氧化还原电位、pH值、Fe2+、Fe3+变化分析,以及浸渣的扫描电镜和能谱分析发现,石英促进黄铜矿浸出主要表现在能缩短微生物浸出的延迟时间,它对浸出过程新生成的沉淀具有吸附作用,能在一定程度上减轻沉淀对黄铜矿浸出的阻碍.     

电位对无捕收剂溶液中黄铜矿表面化学构成的影响

采用循环伏安法、X射线光电子能谱研究了黄铜矿在中性无捕收剂浮选介质中不同电位极化后其表面产物相的化学构成.结果显示黄铜矿在中性无捕收剂溶液中表面相中的S以具有黄铜矿晶体结构的亚稳相缺金属硫化物CuFe1-xS2,CuS2和稳定相多硫化物Sn-的形态存在.当电位提高到0.1 V/SCE,表面相中的Sn-消失,大量的S0和少量高价态(+4/+6)硫相(S2O23-/SO24-)形成.当极化电位大于0.35 V/SCE,表面相中S0的量急剧减小,氧化形成了大量的高价态(+4/+6)硫相(S2O23-/SO24-).表面相中的Cu以CuFe1-xS2的形式存在,高电位下出现少量的CuO相.Fe在低电位...     

细菌-矿物接触/非接触模式下黄铜矿浸出溶解行为

研究细菌-矿物接触模式及利用透析袋将细菌和矿物隔离的非接触模式下嗜酸氧化亚铁硫杆菌对黄铜矿浸出溶解的影响,并对黄铜矿浸出过程表面钝化的原因进行分析。研究结果表明:在细菌-矿物接触模式下,黄铜矿的浸出行为包括细菌对黄铜矿表面硫的催化氧化及细菌氧化Fe2+生成的Fe3+对黄铜矿在于氧化溶解;在细菌-矿物非接触模式下,黄铜矿主要通过细菌氧化Fe2+生成的Fe3+氧化浸出;浸出体系电位是影响黄铜矿浸出速率的主要因素,且较高的电位更有利于黄铜矿的浸出。比较细菌-矿物接触模式和细菌-矿物非接触模式,细菌-矿物接触模式比非接触模式更有利于提高浸出体系电位及氧化消除黄铜矿表面生成的硫膜,因而促进了黄铜矿的浸出;易于在较高电位下生成的黄钾铁矾沉淀是导致这2种模式下黄铜矿表面钝化的主要原因。     

安徽铜陵地区含磁黄铁矿-黄铜矿角闪石巨晶的首次发现

对安徽铜陵曹山中生代辉石闪长玢岩中新发现的含磁黄铁矿-黄铜矿的角闪石巨晶进行了系统分析.岩相学和矿物学研究表明,巨晶角闪石主要为镁绿钙闪石和韭闪石,具幔源角闪石成分特征,结晶于下地壳.磁黄铁矿-黄铜矿集合体多数呈圆柱状形态,在角闪石巨晶中呈平行线状、束状和散点状分布,成分上相对富S但特别贫Ni,是角闪石巨晶亚固相重新平衡的出溶产物.巨晶中FeO和Na 2 O,MgO的变化与硫化物的含量相关.该发现对区域岩浆-成矿作用机制及成矿物质来源研究有重要启示.     

黄铜矿和黄铁矿无捕收剂浮选和分离的研究

本文给出了有、无硫化钠存在时,黄铜矿和黄铁矿的无捕收剂浮选行为。研究表明,黄铜矿具有良好的自诱导可浮性,浮选的电位范围和pH范围较宽;弱酸性和碱性介质中,黄铁矿自诱导浮选差,没有任何可浮电位范围。然而,硫化钠的添加,明显促进了黄铁矿的无捕收剂浮选。天然矿石浮选试验表明,自诱导和硫诱导浮选技术能够有效地浮选和分离黄铜矿和黄铁矿。通过HS~-离子吸附量的测定、矿物表面中性硫量提取分析、矿浆电位测试和量子化学计算,较详细地研究了黄铜矿和黄铁矿无捕收剂浮选的机理。研究结果表明,矿物表面中性硫是主要疏水体。     

Comparative study on the passivation layers of copper sulphide minerals during bioleaching

The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite>bornite>pyritic chalcopyrite>covellite>porphyry chalcopyrite. The residues were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is indicated that jarosite may not be responsible for hindered dissolution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopyrite may strongly hinder copper extraction. X-ray photoelectron spectroscopy (XPS) further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu₄S₁₁, S8, and copper-rich iron-deficient polysulphide Cu₄Fe₂S₉, respectively. The ability of these passivation layers was found as Cu₄Fe₂S₉>Cu₄S₁₁>S₈>jarosite.     

Bioleaching of two different types of chalcopyrite by Acidithiobacillus ferrooxidans

Two different types of chalcopyrite (pyritic chalcopyrite and porphyry chalcopyrite) were bioleached with Acidithiobacillus ferrooxidans ATF6. The bioleaching of the pyritic chalcopyrite and porphyry chalcopyrite is quite different. The copper extraction reaches 46.96% for the pyritic chalcopyrite after 48-d leaching, but it is only 14.50% for the porphyry chalcopyrite. Proper amounts of initial ferrous ions can improve the efficiency of copper extraction for the two different types of chalcopyrite. The optimum dosage of ferrous ions for the pyritic chalcopyrite and porphyry chalcopyrite is different. The adsorption of ATF6 on the pyritic chalcopyrite and porphyry chalcopyrite was also studied in this paper. It is found that ATF6 is selectively adsorbed by the two different types of chalcopyrite; the higher adsorption onto the pyritic chalcopyrite than the porphyry chalcopyrite leads to the higher copper dissolution rate of the pyritic chalcopyrite. In addition, the zeta-potential of chalcopyrite before and after bioleaching further confirms that ATF6 is more easily adsorbed onto the pyritic chalcopyrite.     

Structural,microstructural, and thermal characterizations of a chalcopyrite concentrate from the Singhbhum shear zone,India

The structural and morphological characterizations of a chalcopyrite concentrate, collected from the Indian Copper Complex, Ghatshila, India, were carried out by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The con-centrate powder was composed mainly of free chalcopyrite and low quartz in about 3:1 weight ratio. The particle size was about 100 μm. Spectroscopic studies (FTIR, Raman, UV-visible) of the concentrate supported the XRD findings, and also revealed a marginal oxidation of the sulfide phase. The energy band gap of the sulfide was found to be 3.4 eV. Differential thermal analysis and thermogravimetry of the con-centrate showed a decomposition of chalcopyrite at 658 K with an activation energy of 208 kJ?mol?1, and two successive structural changes of silica at 848 K and 1145 K.     

基于硝酸盐为前驱体的溶胶凝胶法制备CuInSe2薄膜

采用低成本的无机盐为前驱体,通过溶胶凝胶法制备了高质量的黄铜矿结构CulnSe2太阳能电池光吸收层薄膜.先将制备得到的溶胶通过旋涂甩胶的方法成膜,再先后置于氢气中还原和在硒蒸气中进行硒化处理,即可得到所需薄膜.通过XRD,XRF,SEM和Raman散射等对材料的结构和形貌进行表征.结果表明:采用这种简单的方法所制备的薄膜除了具备平整度好、结晶度高和致密性好等优点外,Raman散射还表明薄膜表面不存在Cu2-xSe等杂相,上述优点非常有利于后续高质量的薄膜太阳能电池的制作.最后,讨论了CuInSe2薄膜中分层现象的产生以及形成机理.     

电子束原位合成Fe-Cr-C合金组织及力学性能

应用真空电子束四线段旋转扫描方法，采用4种不同配比的Fe/Cr/C合金粉末，在低合金钢表面原位合成不同性质的表面复合层.通过对熔敷试样进行金相、扫描电镜、X射线衍射分析以及表面显微硬度测试，分析不同配比Fe/Cr/C合金粉末对表面复合层组织及力学性能的影响.结果表明：不同粉末配比所制备的表面复合层差异较大，复合层中碳化物含量随粉末中碳含量的增加而增加，硬度也随之增大；复合层呈现马氏体组织、亚共晶组织、共晶组织和过共晶组织4种不同的组织特征.为获得优良的Fe-Cr-C系耐磨材料提供了重要依据.     

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.