Effect of content and spin state of iron on electronic properties and floatability of iron-bearing sphalerite:A DFT+U study

Iron is an impurity widely occurred in sphalerite,and its effect on sphalerite flotation is complex.In this work,the effects of iron content and spin state on electronic properties and floatability of iron-bearing sphalerite are comprehensively studied using density functional theory Hubbard U(DFT+U)calculations combined with coordination chemistry flotation.The band gap of ideal sphalerite is 3.723 eV,and thus electron transition is difficult to occur,resulting in poor floatability.The results suggest the band gap of sphalerite decreases with increasing iron content.For low iron content,the decreased band gap facilitates electron transition;at this case,Fe^(2+)in a high-spin state possesses oneπelectron pair,which can form a weakπ-backbonding with xanthate,causing increasing floatability.However,for medium and high iron-bearing sphalerite,with the further decrease of band gap,Fe^(2+)is oxidized to Fe^(3+)due to electrochemical interaction,and henceπ-backbonding is eliminated,leading to lower floatability of iron-bearing sphalerite,which is consistent with the flotation experimental results.This work could give a deeper understanding of how sphalerite flotation behaviors are affected by iron content.

Study on the occurrence state of indium in sphalerite of Dulong Sn–Zn–In polymetallic deposit,Southwest China

The Dulong deposit,located in the Laojunshan area of southeastern Yunnan,China,is an important polymetallic deposit due to its high reserves of tin,zinc,and indium.The occurrence state of indium is critical for understanding its supernormal enrichment mechanism.Previous studies investigated the occurrence state of indium(including the valence state)based on the indium content in sphalerite and the correlation between metal concentrations.However,more evidence is needed to better constrain indium occurrence at the micro-,nano-,or even atomic scale.In this study,EPMA-FIB-SEM-TEM and XPS techniques were employed to investigate the indium distribution characteristics and occurrence state in sphalerite from the Dulong Sn–Zn–In polymetallic deposit.The maximum concentration of indium in the indium-rich sphalerite samples is 0.37%,and the results of the EPMA analysis showed a relatively homogeneous distribution of indium in sphalerite.The FIB-SEM-TEM results demonstrated that the lattice stripes of sphalerite were periodically and continuously distributed at the nanoscale,confirming that sphalerite in the deposit was an excellent single crystal structure,and the peak heights of the various characteristic peaks of indium in the EDX spectra were relatively close to each other,with no distinct peaks of high indium content.In addition,the XPS results indicate that the element valence state of indium in sphalerite is In^(3+),and it combines with S^(2-)to form a bond.These results indicate that indium in sphalerite of the Dulong deposit is uniformly distributed at both the micro-and nanoscale,and there is no indium-independent mineral.In^(3+)enters the crystal lattice of sphalerite by replacing Zn2+in the form of isomorphic substitution.

豫西熊耳山蒿坪沟Ag-Au-Pb-Zn多金属矿床闪锌矿矿物学和微量元素组成特征及其成矿启示

蒿坪沟银金铅锌多金属矿床是豫西熊耳山地区重要的铅锌多金属矿床之一,矿体主要赋存在蚀变破碎带和断裂带内,成矿与区内岩浆活动关系密切。目前该矿床的研究集中于同位素地球化学、成矿时代和成矿物质来源等方面,但从矿物角度示踪成矿过程的报道较少。本文以矿石中不同世代闪锌矿为研究对象,开展电子探针和LA-ICP-MS原位主微量元素分析,查明不同世代闪锌矿的矿物学和微量元素组成特征,以反演矿床成矿物理化学条件进而约束矿床成因类型。结果表明,该矿床中闪锌矿主要存在两个世代:第一世代闪锌矿(Sp1)呈黑褐色或浅褐色,常与黄铁矿和黄铜矿共生,相对富集Fe、Mn、Cd、Cu和In;第二世代闪锌矿(Sp2)呈黄褐色或暗褐色,与大量方铅矿共生,裂隙被它形黄铁矿和碳酸盐充填,相对富集Co、Ge、Sn和Pb。闪锌矿中主要富集的元素为Fe、Co和In,其中Fe、Mn、Cd、Co和In等元素基本是以类质同象的形式赋存在闪锌矿的矿物晶格中,而Ag、Sb、Cu和Pb可能是以子矿物或显微包裹体的形式赋存。此外,Zn/Cd、Zn/Fe和Ga/In比值以及Fe温度计指示闪锌矿形成于中低温(沉淀时流体温度为229~259℃)和低硫逸度(lgƒ(S_(2))=-12.0~-10.1)的环境下,由成矿阶段II(Sp1到成矿阶段Ⅲ(Sp2其成矿温度可能发生了显著变化,结合面扫描分析结果,指示闪锌矿从核部到边缘温度逐渐降低。通过与国内外典型铅锌矿床闪锌矿微量元素特征对比,结合本矿床闪锌矿中低的Ga/In和Ge/In比值及Ge含量的特征,指示蒿坪沟银金铅锌多金属矿床成矿过程有岩浆活动的参与。综合认为蒿坪沟银金铅锌多金属矿床可能属于岩浆期后热液蚀变岩型和脉型矿床。

我国闪锌矿中Ge资源富集与提取研究进展

Ge是一种战略性稀散金属,在现代工业中发挥着重要作用。闪锌矿作为Ge最主要的载体矿物,是工业上提取回收Ge的重要来源,闪锌矿提Ge在Ge资源开发中占据重要地位。分别从闪锌矿中Ge的赋存状态、载Ge闪锌矿的浮选理论工艺及药剂研究、硫化锌冶炼过程中Ge的迁移与富集规律和从含Ge冶炼富集物中深度富集回收Ge的方法与工艺等方面,系统概述了近年来我国闪锌矿中Ge资源富集与提取技术开发和工业实践的现状。闪锌矿中Ge主要以类质同象形式存在,Ge取代导致闪锌矿的铜活化和黄药捕收活性降低、浮选回收难度增加。工业实践表明,通过优化载体矿物载锗闪锌矿的浮选药剂和工艺,可在一定程度上提升硫化锌精矿中Ge回收效果。在目前常用的硫化锌冶炼工艺中,形成的含Ge富集物主要包括真空炉渣、浸出渣、氧化锌烟尘、锗铁渣、中和渣、置换渣等。针对上述Ge富集物,目前形成了以火法富集、浸出法、沉淀法、萃取法和离子交换法等为主的Ge深度富集提取技术,其中浸出—沉淀/溶剂萃取的发展和应用最为成熟。在分析发展现状的基础上,提出需从重视选别阶段Ge回收指标提升、改进冶炼工艺的提升Ge在冶炼产物中富集程度和强化Ge萃取分离技术开发及工业化应用3个方面进一步提高我国闪锌矿中Ge资源富集提取技术水平。

安徽庐枞盆地西湾铅锌矿床闪锌矿中镉的赋存状态和富集机制研究

镉(Cd)是一种重要的关键金属元素,对国家安全和新兴产业发展具有重大意义。闪锌矿是最具经济意义的富镉矿物,查明闪锌矿中镉的赋存状态,对研究镉的富集机制具有重要的意义;但受限于研究手段,闪锌矿纳米尺度上镉的赋存状态研究仍相对薄弱。西湾矿床是长江中下游成矿带庐枞矿集区内新发现的大型铅锌矿床,矿床中产出富镉闪锌矿。本次研究使用LA-ICP-MS对闪锌矿进行原位微量元素含量和Mapping分析,查明闪锌矿微米尺度镉的分布规律;在此基础上使用扫描透射电镜(STEM)查明纳米级闪锌矿的微观形貌和高分辨原子像,明确纳米尺度镉的赋存状态。研究结果表明,西湾矿床闪锌矿中镉含量的变化范围为2186×10^(-6)~9859×10^(-6),镉在闪锌矿中分布不均匀,闪锌矿孔洞发育的区域相对富镉,而闪锌矿均质区域相对贫镉。通过高分辨原子像的晶面间距和原子线扫描结果,确定西湾矿床闪锌矿中Cd原子以原位替代Zn原子的形式赋存在闪锌矿晶格中,未发现纳米级镉的独立矿物。对比金顶和牛角塘等富镉铅锌矿床,长江中下游成矿带的铅锌矿床中平均镉含量不高,推测成矿带可能缺乏充足的镉物质来源。

贵州半边街锗锌矿床锗的富集特征及其地质意义

锗(Ge)属于战略性关键矿产资源,是众多高新技术领域的重要原材料。Ge主要以共/伴生形式产出于Zn、Pb和Cu等热液贱金属矿床和煤矿床中,目前全球Ge资源主要来源于铅锌矿的副产品。近期取得较大找矿突破的半边街锌矿床(7.70Mt矿石,Zn平均品位5.1%)伴生有超大型规模的金属Ge(>900t@110×10^(-6)),然而Ge超常富集的机制不清。本次研究利用LA-ICPMS对闪锌矿进行了微区原位微量元素组成和Mapping分析,以揭示Ge等元素的富集特征、赋存状态和替代方式,探讨Ge的富集机制。分析结果表明,半边街矿床闪锌矿中高含量(平均值>100×10^(-6))微量元素有Fe、Pb、Ge和Cd等,较高含量(平均值100×10^(-6)~10×10^(-6))的有Mn、Ga、Sn和Tl,以及较低含量(平均值<10×10^(-6))的有Ag、Cu、In和Sb。相比于各类型铅锌矿床,半边街闪锌矿Ge超常富集(274×10^(-6)~1938×10^(-6),平均为1055×10^(-6),达到1000倍富集)。该矿床中Ge以类质同象或纳米颗粒形式赋存于闪锌矿中。微量元素摩尔量相关性图揭示Ge替代Zn的方式以Ge^(4+)+Pb^(2+)3Zn^(2+)为主,其次为nGe^(4+)+Mn 2+(2n+1)Zn^(2+)和nGe^(4+)+2Tl^(3+)(2n+3)Zn^(2+)。综合分析认为,半边街矿床Ge可能来源于相对富Ge的前寒纪基底;富有机质的盆地流体在Ge的搬运中发挥重要作用;Ge、Cd等稀散元素的共生分异制约了Ge的最终超常富集。因此,半边街矿床中Ge的超常富集是“源、运、聚”复杂过程多要素耦合作用的结果。

下庄新桥西铀矿床硫化物地球化学特征及其地质意义

新桥西铀矿床为下庄矿田内的铀矿床之一,位于贵东岩体东部。文章利用电子探针分析技术(EPMA)测定了新桥西铀矿床中黄铁矿、闪锌矿的微量元素组成。数据显示,该矿床中黄铁矿、闪锌矿具富Fe、Zn亏S的特征,其中黄铁矿主要富集Mo、Mn、Cu、Zn、As、Co、Ni、Pb、U;闪锌矿富集Mo、Mn、Fe、Cu、Cd。Cu、Fe、As、Co、Ni、Zn、Pb、Mo及Mn等微量元素可能以矿物包体或类质同象的形式存在于黄铁矿和闪锌矿中;黄铁矿中Co、Ni、Mo、As与U在流体中具相似的地球化学行为,可能具有相似的物质来源。硫化物微量元素特征指示其主要形成于中-浅部、中温成矿环境。结合下庄矿田的成矿地质背景,认为新桥西铀矿床属于典型的岩浆热液型矿床。

桂西北箭猪坡铅-锌-锑多金属矿床成因:来自闪锌矿微量、稀土元素及氢氧同位素的证据

位于广西右江盆地北东侧的丹池成矿带是中国南方重要的有色金属矿集区,箭猪坡矿床是其南段五圩矿田中规模最大、成矿特征最具代表性的大型铅-锌-锑多金属矿床,由长期开采的脉状铅-锌-锑矿体和新发现的似层状锡多金属矿体组成。通过闪锌矿的微量、稀土元素和氢-氧同位素分析,对比研究2类矿体成矿特征的差异,进一步探讨成矿流体来源及矿床成因类型。分析结果显示:箭猪坡矿床不同类型矿体中闪锌矿均相对富集Fe、Cu、Pb、Sn、Sb,亏损Ga、Ge、Co、Ni,与典型的岩浆热液型矿床相似。同时,似层状矿体中稀土元素总量(ΣREE=12.80×10^(-6)~44.31×10^(-6))高于脉状矿体(ΣREE=3.34×10^(-6)),具有明显的轻、重稀土元素分馏和Eu亏损。闪锌矿氢-氧同位素分析结果中,脉状矿体δD=-81.8‰~-69.2‰,δ^(18)O=2.1‰~5.2‰;似层状矿体δD=-109.4‰~-75.2‰,δ^(18)O=-4.0‰~4.0‰,指示2类矿体的成矿流体为岩浆热液与大气降水不同比例的混合流体。以上特征表明,箭猪坡矿床属于岩浆热液型铅锌矿床,脉状矿体和似层状矿体成矿物质(流体)主要来源于岩浆热液。

滇西阿面根铅锌矿床成因研究——硫、铅同位素和闪锌矿微量元素证据

保山地块南部的芦子园地区是我国西南重要的铁铜铅锌多金属矿集区之一,阿面根铅锌矿床是该区近年来新发现的铅锌矿床,但目前研究程度低,成矿物质来源、矿床成因不明。本文在详细的野外地质调查和显微观察基础上,通过阿面根矿床的金属硫化物硫同位素、铅同位素探讨矿质来源,利用闪锌矿微量元素特征判定矿床成因。结果显示,阿面根矿床硫化物的δ~(34)SV-CDT值(9.44‰~12.16‰)介于壳源花岗岩硫与围岩地层同期海水硫之间,显示出二者混合特征;铅主要来自上地壳;闪锌矿以富集Fe、Mn、Co、Cu、Cd而贫Ga、Ge、As、Sn、Cr、Ni为特征,其中Fe、Cd、Mn、Co、Ag、Sb、Ga主要以类质同象形式产出,Cu则以类质同象和矿物包裹体的形式同时进入闪锌矿晶格中,可能存在Zn^(2+)↔Fe^(2+)、Zn^(2+)↔Cd^(2+)、2Zn^(2+)↔Ag^(+)+Sb^(3+)等方式的替代关系;闪锌矿微量元素组成特征与VMS型、MVT型、矽卡岩型和浅成低温热液型矿床中的闪锌矿明显不同,其Cd/Fe(0.02~0.04,均值0.03)、Co/Ni(15~1 019,均值1 275)和Ga/In(0.11~1.10,均值0.31)比值特征和较低的Ge元素含量均表明闪锌矿形成与岩浆热液关系密切。综上证据,本文认为阿面根矿床的成矿物质主要来源于深部隐伏中酸性侵入岩,有少量地层围岩物质加入。结合矿床地质特征,认为阿面根矿床属于岩浆热液充填交代型铅锌矿床。

KINETICS OF LEACHING SPHALERITE WITH PYROLUSITE SIMULTANEOUSLY BY MICROWAVE IRRADIATION

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Trace Elements in Sphalerite from the Dadongla Zn-Pb Deposit, Western Hunan-Eastern Guizhou Zn-Pb Metallogenic Belt, South China

The western Hunan-eastern Guizhou Zn-Pb metallogenic belt is one of the important Zn-Pb mineralization regions in China.The Dadongla deposit,located in the northeast of Guizhou Province,is one of the typical Zn-Pb deposits in the region and has estimated resources more than 12 million metric tons(Mt)with an average grade of 4.11 wt%Zn+Pb.Its orebodies are hosted in the lower Cambrian Aoxi Formation dolomite,occurring as bedded,para-bedded in shape,and in conformity with the wall rock.The ore mineral assemblage is simple,dominated by sphalerite with minor pyrite and galena,and the gangue minerals are composed of dolomite,calcite with minor bitumen and barite.In view of the lack of geological and geochemical researches,the genesis of Zn-Pb ore is still unclear.Laser ablation-inductively coupled plasma mass spectrometry(LA-ICPMS)spot and mapping analyses were used to obtain sphalerite trace element chemistry in the Dadongla Zn-Pb deposit in Guizhou,China,aiming to constrain its ore genesis.The results show that sphalerite is characterized by the enrichment of Cd,Fe,Ge and Hg,corresponding with that of typical MVT deposits.Four zones were identified in the sphalerite crystal from Dadongla from the center to margin according to the color bands.in which the zone in the center,representing the early ore-stage sphalerite,is characterized by enrichment of Cd relatively,while the zone forming at late ore-stage is enriched in Ge and Hg relatively.The finding was controlled by differential leached metals content in ore-forming fluid from its source rock.Notably,critical element Ge trends to be enriched at the late ore-stage and follows a substitution of 2 Zn^2+(?)Ge^4++□(vacancy).Moreover,the calculated ore-forming temperature ranges from 79.9℃to 177.6℃by the empirical formula,which is similar to that of typical Mississippi Valley-type(MVT)deposits.Compared with the features of trace elements in sphalerite from different types of deposits,together with the geology,the Dadongla deposit belongs to an MVT Zn-Pb deposit.

THE KINETICS OF FERRIC CHLORIDE LEACHING OF SPHALERITE IN THE MICROWAVE FIELD

The kinetics of ferric chloride leaching of sphalerite in the microwave field has being studied in this paper.According to the experimental data,the rate of dissolution of sphalerite microwave irradiation heating is faster than that with conventional heating.The dissolution of sphalerite in the microwave field was investigated in different condition of temperature,concentration of FeCl,and particle size and a nonisothermal kinetic equation has being obtained.

Timing of formation of the Hongdonggou Pb-Zn polymetallic ore deposit,Henan Province,China:Evidence from Rb-Sr isotopic dating of sphalerites

The Hongdonggou Pb-Zn polymetallic ore deposit,located in the southwestern part of the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore mineralization in Henan Province,China,is an important part of the East Qinling metallogenic belt.The orebodies in the deposit,which are vein,bedded and lenticular,are mainly hosted in the syenite porphyry,and formed within the carbonate and clastic rocks of the Yuku and Qiumugou formations partially.The genesis of the deposit has previously been argued to be of hydrothermal-vein type or of skarn-hydrothermal type.In this study,we report the results of Rb-Sr isotopic dating based on sphalerites from the main orebody of the Hongdonggou Pb-Zn polymetallic ore deposit,which yield an isochron age of 135.7 ± 3.2 Ma,constraining the timing of mineralization as early Cretaceous.The age is close to those reported for the Pb-Zn deposits in the Luanchuan ore belt.The(^(87)Sr/^(86)Sr),values of the sphalerites(0.71127 + 0.00010) are lower than that of terrigenous silicates(0.720) and higher than the mantle(0.707),suggesting that the metallogenic components were mainly derived through crust-mantle mixing.Combining the results from this study with those from previous work,we propose that the Hongdonggou Pb-Zn polymetallic ore deposit is a hydrothermal-vein deposit associated with the early Cretaceous tectonothermal event,and the mineralization is controlled by NWand near EW-trending faults in the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore concentration belt.

Cu^2+-catalyzed mechanism in oxygen-pressure acid leaching of artificial sphalerite

The potential autoclave was used to study the catalytic mechanism of Cu^2+during the oxygen pressure leaching process of artificial sphalerite.By studying the potential change of the system at different temperatures and the SEM–EDS difference of the leaching residues,it was found that in the temperature range of 363–423 K,the internal Cu^2+formed a Cu S deposit on the surface of sphalerite,which hindered the leaching reaction,resulting in a zinc leaching rate of only 51.04%.When the temperature exceeds 463 K,the system potential increases steadily.The increase in temperature leads to the dissolution of the CuS,which is beneficial to the circulation catalysis of Cu^2+.At this time,the leaching rate of Zn exceeds 95%.In addition,the leaching kinetics equations at 363–423 and 423–483 K were established.The activation energy of zinc leaching at 363–423 and 423–483 K is 38.66 and 36.25 kJ/mol,respectively,and the leaching process is controlled by surface chemical reactions.

An electrochemical investigation on collectorless flotation of sphalerite in presence of Cu^(2+) ions

The collectorless flotation behaviors of sphalerite in the presence of Cu 2+ ions have been established. The effects of pH, potential and Cu 2+ concentration on the flotation have been studied using a micro flotation cell specially designed, where the potential can be controlled by a potentiostat. The flotation results have shown that the Cu activated sphalerite displays a good collectorless floatability in a pH range of 0～13. The higher potentials can improve the flotation recovery. The surface species formed during the Cu ion activation have been examined using a special electrochemical technique—a composite sphalerite electrode. Zinc deficient sulfide (Zn 1- x Cu x S) and Cu poly sulfide (Cu y+z S y ) species have been determined. They are responsible for the collectorless flotation of sphalerite. In additional, they can improve the conductivity of the sphalerite surface.

Quantum-mechanical study of effect of lattice defects on surface properties and copper activation of sphalerite surface

The electronic properties of sphalerite(110)surface bearing Fe,Mn and Cd impurities were calculated using density-functional theory,and the effects of impurities on the copper activation of sphalerite were investigated.Calculated results indicate that both Fe and Mn impurities narrow the band gap of sphalerite surface and lead to the Fermi level shifting to conduction band.Impurity levels composed of Fe 3d and Mn 3d orbital appearing in band gap are beneficial to electrons transfer from the valence band to the conduction band and promote the surface conductivity and the electrochemical activity.The results show that Fe and Mn impurities cannot be replaced by Cu atom,which reduces the exchange sites(Zn)for Cu atom,hence Fe-and Mn-bearing sphalerites are hard to be activated by copper.Cd impurity has little effect on electronic structure of sphalerite surface;however,Cd atom is easily replaced by Cu atom,and this is the reason why the Cd-bearing sphalerite can be easily floated.

Sphalerite Chemistry, Niujiaotang Cd-Rich Zinc Deposit, Guizhou, Southwest China

Sphalerite in the Niujiaotang Cd rich zinc deposit, Duyun, Guizhou is characteristically light yellow in color with significant enrichment of cadmium which ranges from 0.83% to 1.97% (averaging 1.38%) in concentration in the mineral, corresponding to an enrichment coefficient as high as 30.47 to 72.96. In comparison with other major Pb Zn deposits in the world (the Mississippi Valley deposits, and the Fankou and Jinding deposits in China) the Niujiaotang deposit is n-n×10 times richer in cadmium. Sphalerite in the deposit is also rich in Ga and Ge, but poor in In, Mn and Fe, suggesting some special mechanisms that govern the geochemical behavior of these trace elements. Except for a minor amount of independent minerals like greenockite, cadmium occurs mainly as isomorphous impurity in the crystal lattice of sphalerite. During weathering and leaching under supergene condition, cadmium was separated from Zn, resulting in some secondary minerals of Cd, including oxides and otavite.

Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy:Sphalerite as an Example

包括矿物质，分子和离子，一些材料的拉曼频率与改变压力和温度系统地变。这个性质经常与热水的钻石铁砧房间(HDAC ) 在高压力实验被用作一个压力计量器。因为液体包括的系统类似于 HDAC 的，决定液体包括的内部压力能也被用来。闪锌矿是一种普通女儿矿物质。在这研究，闪锌矿的 350 厘米 −1 山峰的频率移动用 HDAC 从 296 ～ 523 K 并且从 0.07 ～ 2.00 GPa 被学习了。等温线的全球斜坡(∂V 350/∂p) T 在学习压力范围是 0.0048。有温度的斜坡的重要变化都没被观察。在闪锌矿和压力和温度的 350 厘米 −1 山峰的频率移动之间的关联作为 P=208.33 被抑制(ΔV p )350+3.13T 943.75。这种关系可以被用来估计忍受闪锌矿的液体包括的内部压力。

Effect of vacancy defects on electronic properties and activation of sphalerite(110) surface by first-principles

The electronic properties of sphalerite(110) surface with Zn-vacancy and S-vacancy were calculated by using density-functional theory,and the effects of vacancy defect on the copper activation of sphalerite were investigated.The calculated results indicate that surface state occurs in the band gap of Zn-vacancy sphalerite,which is from the contribution of S 3p orbital at the first layer of the surface.The presence of S-vacancy results in surface state appearing near the Fermi level and the bottom of conductor band,which are composed of S 3p and Zn 4s orbital,respectively.The surface structure of Zn-vacancy sphalerite is more stable than S-vacancy surface due to the occupation of Zn-vacancy by Cu atoms;hence,the substitution reaction of Cu for Zn vacancy is easier than the substitution of Cu for Zn atoms with S-vacancy surface.

Bioleaching of sphalerite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans cultured in 9K medium modified with pyrrhotite

Elective culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in 9K medium modified with pyrrhotite was studied.Bioleaching of flotation concentrate of sphalerite by the selected bacteria was carried out.The results show that the microorganisms cultured by pyrrhotite are a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans,of which the capability to oxidize ferrous to ferric irons is enhanced by the high mass ratio of Fe to S in pyrrhotite.Three pyrrhotite samples were separated into various parts with corresponding S/Fe ratios by magnetic separation and were used to culture the elective bacteria as the substrate.The association of the cultures could provide a more rapid and complete oxidation of sphalerite than that of bacteria cultivated by conventional methods.