Effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores

The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM-EDS. The results indicated that at ambient temperature, the easily leached copper oxide minerals were completely dissolved, while the bonded copper minerals were insoluble. At lukewarm temperature of 40℃, it was mainly the dissolution of copper in isomorphism state. With increasing temperature to 60℃, the copper leaching rate in the adsorbed state was significantly accelerated. In addition, when the temperature increased to 80℃, the isomorphic copper was completely leached, leaving 11.2% adsorbed copper un-leached. However, the copper in feldspar-quartz-copper-iron colloid state was not dissolved throughout the leaching process. Overall, the leaching rates of copper in different copper minerals decreased in the order: malachite, pseudo-malachite > chrysocolla > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite > feldspar-quartz-copper-iron colloid.

Analysis of the microstructure and elemental occurrence state of residual ash-PM following DPF regeneration by injecting oxygen into non-thermal plasma

Particulate matter(PM)capture tests were carried out on clean diesel particulate filters(DPFs)under different loads(25%,50%,75%and 100%).DPFs were regenerated by a non-thermal plasma(NTP)injection device.Raman spectroscopy and x-ray photoelectron spectroscopy were used to investigate changes in the microstructure and element occurrence state of the sediment in DPF channel before and after regeneration.The order of the PM samples decreased before NTP treatment as the load increased;the amorphous carbon content was high,and the oxidationactivity was higher.After NTP treatment,the carbon atoms at the edge of the microcrystalline structure in the ash-PM samples were oxidized,and the structure was reorganized;in addition,the amorphous carbon content decreased,and the structure was more diversified.Before NTP,the C element of PM samples was the main component,and the content of the O element was relatively low.The C element occurred in the form of C–C,C–OH,and O–C=O functional groups,and O atoms were mainly combined with C–O.After NTP,the content of Na,P,S,Ca,and other inorganic elements in ash-PM samples was prominent because C atoms were removed by NTP active substances.There were two forms of S element occurrence(SO42-and SO32-);the proportion of SO42-was approximately 40%,and the proportion of SO32-was approximately60%.Study of the microstructure and element occurrence of the residues in the DPF channels improved our understanding of the mechanism of the low-temperature regeneration of DPFfrom NTP.

Chemical composition of the ore and occurrence state of the elements in Jingbaoshan platinum-palladium deposit

The Jingbaoshan platinum-palladium deposit is China’s largest independent PGM (platinum-group met- als) deposit so far discovered. There are eleven kinds of useful components in the ore: Pt, Pd, Os, Ir, Ru, Rh, Au, Ag, Cu, Ni, and Co. The platinum-group elements, gold and silver occur in the form of minerals in ores. twenty-five kinds of precious metal minerals have been found, of which twenty one belong to the platinum-group minerals. The minerals are very small in grain size. Copper occurs mainly as copper sulfide with a small amount of free copper oxide, and the beneficiated copper accounts for 95.21%. Nickel occurs mainly as nickel sulfide, and some nickel silicate and nickel oxide occur in the ore. The beneficiated nickel accounts for 72.03%. Cobalt occurs mainly as co- balt sulfide, and there are some cobalt oxide and other kinds of cobalt. The beneficiated cobalt accounts for 77.58%.

The occurrence state of vanadium in the black shale-hosted vanadium deposits in Shangling of Guangxi Province, China

The Shangling vanadium deposit, which occurs in the Lower Devonian Tangding formation black rock series strata, has V2O5 reserves of more than 1.5 million tons and prospective reserves of more than 2 million tons. Preliminary studies on the occurrence state of vanadium(V) in this deposit have been conducted by artificial heavy minerals concentrates, leaching experiments, scanning and transmission electron microscopy and X-ray powder diffraction.These experiments have revealed no independent vanadium mineral occurrences in the Shangling vanadium deposit and the percentages of water-soluble vanadium, hydrochloric acid soluble vanadium and HF soluble vanadium were1.93 %, 21.42 % and 76.47 %, respectively. Based on our data and earlier research, we estimate that the valences state of V absorbed onto the surface of organic matter or clastic particles are +5 and +4, accounting for 10.00 % and13.35 % of the total amount of V, respectively and the valences state of V that exist in the octahedral crystal lattice of authigenic illite include +3 and +4, accounting for71.64 % and 4.83 % of the total amount of V, respectively.By calculating the correlation between the total organic carbon and V, we infer that after deposition and before entering the crystal lattice of illite, V occurs in the form of humate complex or is adsorbed by organic matter. About4.24 % of the Al is in the octahedral crystal lattice of illite,which was replaced by the vanadium under the metallogenic environments of Shanglin.

THE INFLUENCEN OF STAND STATE ON THE OCCURRENCE OF DENDROLIMUS SUPERANS (BUTLER) IN DAXING'AN MOUNTAINS

Dendrolimus superans (Butler) occurred in the vast areas of Daxing'an Mountains forest. in Heilongjiang Province, in 1990. Stands damaged by D.Superans seriously, intermediately and lightly show patch shape distribution within damaged area. By ordination analysis and correlation analysis between ordination factors and coordinate axis. It was found that occurrence of D. Superans in different extent is owing to the effect of forest age. composition and exposure. The tended young pure forests grown on the sunward slopes are most seriously damaged and non-tended middle-age mixing stands grown on the sunless slopes are most lightly damaged. Therefore, in order to prevent D.superans from seriously damaging larch forests. relatively large crown density (P>0. 7) should be kept,and broadleaftrees should be also properly preserved.

Occurrence state and oil content evaluation of Permian Fengcheng Formation in the Hashan area as constrained by NMR and multistage Rock-Eval

The Hashan area,neighboring the Mahu Sag that is rich in the shale oil resources,showed commercial oil flow in the corresponding lacustrine shales of the Lower Permian Fengcheng Formation(P)with reserve scale approximately 789 million tons,presenting great potential for oil exploration.Despite their geographical proximity,the hydrocarbon occurrence and oil-bearing capacity of shale in the Hashan area and Mahu Sag greatly differ owing to the complex tectonic evolution.Therefore,understanding the occurrence state and oil content of the Pif in the Hashan area is crucial for ongoing shale oil exploration activities and the development of the northwestern margin of the Junggar Basin.In this study,an in-tegrated investigation,including petrological observations,scanning electron microscopy(SEM)obser-vation,analysis of nuclear magnetic resonance(NMR)Ti-T2 spectra,and conventional and multistage Rock-Eval pyrolysis methods were conducted to evaluate the occurrence state and oil content of the Pif shale in the Hashan area.The results indicate that plagioclase(average 30.7%)and quartz(24.1%)dominate the mineral compositions of the Pf shale samples.A method involving quartz-plagioclase-carbonate minerals is proposed to conduct lithofacies classification.In the Hashan area,the organic matter abundance in the Pf shale is scaled in fair to good range,the thermal maturity ranges from immature to early mature stage,and the primary organic matter types are Types I and Ilj.Intergranular and dissolution pores are the two most common pore types.The free oil is mostly found in the pores and microfractures of the mineral matrix,whereas the adsorbed oil is mostly adsorbed on the surfaces of kerogen and clay minerals.The high organic matter abundance,quartz content,and porosity account for substantial increase in the oil content,the area rich in shale oil resources coincides with that rich in free oil.The most favorable lithofacies in the Hashan area is the calcareous mudstone/shale,which hosts the highest free oil content(average 2.49 mg),total oil content(15.02 mg/g),organic matter abundance CTOC:1.88% and S_(1)+S_(2)=20.54mg/g and orositv(5.97%)

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.

The occurrences and geochemical characteristics of thorium in iron ore in the Bayan Obo deposit, Northern China

The Bayan Obo deposit in northern China is an ultra-large Fe–REE–Nb deposit.The occurrences,and geochemical characteristics of thorium in iron ores from the Bayan Obo Main Ore Body were examined using chemical analysis,field emission scanning electron microscopy,energy dispersive spectrometer,and automatic mineral analysis software.Results identified that 91.69%of ThO2 in the combined samples was mainly distributed in rare earth minerals(bastnaesite,huanghoite,monazite;56.43%abundance in the samples),iron minerals(magnetite,hematite,pyrite;20.97%),niobium minerals(aeschynite;14.29%),and gangue minerals(aegirine,riebeckite,mica,dolomite,apatite,fluorite;4.22%).An unidentified portion(4.09%)of ThO2 may occur in other niobium minerals(niobite,ilmenorutile,pyrochlore).Only a few independent minerals of thorium occur in the iron ore samples.Thorium mainly occurs in rare earth minerals in the form of isomorphic substitution.Analyses of the geochemical characteristics of the major elements indicate that thorium mineralization in the Main Ore Body was related to alkali metasomatism,which provided source material and favorable porosity for hydrothermal mineralization.Trace elements such as Sc,Nb,Zr,and Ta have higher correlation coefficients with thorium,which resulted from being related to the relevant minerals formed during thorium mineralization.In addition,correlation analysis of ThO2 and TFe,and REO and TFe in the six types of iron ore samples showed that ThO2 did not always account for the highest distribution rate in rare earth minerals,and the main occurrence minerals of ThO2 were closely related to iron ore types.

Microscopic oil occurrence in high-maturity lacustrine shales:Qingshankou Formation,Gulong Sag,Songliao Basin

Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sag,Songliao Basin is a classic lacustrine pure shale reservoir that contains abundant shale oil resources.The predicted geological reserves of the shale are 1.268×10^(9) t.In this study,field emission scanning electron microscope(FE-SEM),the modular automated processing system(MAPS),pyrolysisgas chromatography(Py-GC),low-pressure nitrogen gas adsorption(LPNA),Soxhlet extraction,pyrolysis,and 2-D nuclear magnetic resonance(NMR)were integrated to describe the shale oil components,microscopic occurrence,mobility,and the effective pore size distribution.Meanwhile,the related controlling factors are discussed.The shale oil in the Qingshankou Fm exists dominantly in the matrix pores of the clay minerals,with small amounts distributed in the intergranular pores of terrigenous clastic grains,intercrystalline pores of pyrite,intragranular pores of ostracod shells,and micro-fractures.Shale oil is distributed in the pore spaces of variable sizes in different lithofacies.The clay mineral-laminated shales are characterized by the broadest range of pore size and largest volume of pore spaces with shale oil distribution,while the ostracod-laminated shales have limited pore spaces retaining oil.Furthermore,the proposed integrated analysis evaluates the shale oil molecules existing in two states:movable,and adsorbed oil,respectively.The result illustrates that movable oil takes up 30.6%e79.4%of the total residual oil.TOC,mineral composition,and pore structures of the shale joint together to control the states and mobility of the shale oil.TOC values are positively correlated with the quantities of shale oil regardless of the state of oil.The mineral components significantly impact the state of shale oil.Noticeable differences in the states of oil were observed following the changing types of minerals,possibly due to their difference in adsorption capacity and wettability.Clay minerals attract more adsorbed oil than movable oil.Felsic minerals generally decrease the occurrence of total and adsorbed oil.Carbonate plays a positive role in hydrocarbon retention of all the shale oil states.As for the pore structure,the average pore size exerts a critical impact on the total,movable,and adsorbed oil content.The total pore volume and specific surface area of shales play a principal role in controlling the total yields and amounts of adsorbed oil.This research improves the understanding of the occurrence characteristics and enrichment mechanisms of shale oil in terrestrial pure shales and provides a reference for locating favorable shale oil exploration areas.

Control of micro-wettability of pore-throat on shale oil occurrence:A case study of laminated shale of Permian Lucaogou Formation in Jimusar Sag,Junggar Basin,NW China

The control of micro-wettability of pore-throat on shale oil occurrence in different types of reservoir spaces remains unclear.Take the shale oil reservoir of the Permian Lucaogou Formation in the Jimusar Sag,Junggar Basin as an example,the reservoir space in laminated shale and the control of micro-wettability of pore-throat on shale oil occurrence were studied by using scanning electron microscope(SEM),multi-stage pyrolysis,quantitative fluorescence,nuclear magnetic resonance(NMR)and other techniques.The results show that there are mainly two types of laminated shale in the Lucaogou Formation,namely laminated shale rich in volcanic materials+terrigenous felsic,and laminated shale rich in volcanic materials+carbonate.The former type contains feldspar dissolution pores and intergranular pores,mainly with felsic mineral components around the pore-throats,which are water-wet and control the free shale oil.The latter type contains carbonate intercrystalline pores and organic pores,mainly with oil-wet mineral components around the pore-throats,which control the adsorbed shale oil.The oil-wet mineral components around the pore-throats are conducive to oil accumulation,but reduce the proportion of free oil.In the Lucaogou Formation,free oil,with high maturity and light quality,mainly occurs in the laminated shale rich in volcanic materials+terrigenous felsic.

Mineral occurrence for Dachang gold deposit and its impact on gold recovery rate in Qumarleb County,Qinghai

Based on X-ray diffraction,optical microscopy and scanning electron microscopy analysis of the Dachang gold ore,it is showed that the sulfide of ore is the main carrier minerals of gold. A majority of gold is embedded in pyrite and tetrahedrite as the form of inclusion and a small amount intergrowth with pyrite and gangue mineral,occasionally the presence is in form of monomer natural gold. The main factors which influence the recovery rate are sulfide mineral particle size,and the fine grained sulfide is beneficial for the dissociation and flotation of gold bearing minerals. The monomer dissociation degree of gold bearing minerals can reach91. 3%,when the grinding fineness is less than 0. 074 mm and grain level accounts as 80%. It is not conducive to the flotation of sulfide if the grinding fineness is low or high. It is difficult to completely dissociate the monomer if there is a small amount of pyrite and arsenopyrite in the ore. Therefore,before leaching the gold,it must conduct pretreatment to reach the ideal recovery rate of the gold,like roasting oxidation,pressure oxidation and biological oxidation. The fine microscopic gold has little influence on the gold recovery rate.

Statistical Analyses of Sea State Conditions in South China Sea

The statistical characterization of sea conditions in the South China Sea(SCS) was investigated by analyzing a 30-year(1976–2005) numerically simulated daily wave height and wind speed data. The monthly variation of these parameters shows that wave height and wind speed have minimum values of 0.54 m and 4.15 ms^(-1), respectively in May and peak values of 2.04 m and 8.12 ms^(-1), respectively in December. Statistical analysis of the daily wave height and wind speed and the subsequent characterization of the annual, seasonal and monthly mean sea state based on these parameters were also done. Results showed that, in general, the slight sea state prevails in the SCS and has nearly the highest occurrence in all seasons and months. The moderate sea condition prevails in the winter months of December and January while the smooth(wavelets) sea state prevails in May. Furthermore, spatial variation of sea states showed that calm and smooth sea conditions have high occurrences(25%–80%) in the southern SCS. The slight sea condition shows the largest occurrence(25%–55%) over most parts of the SCS. High occurrences(8%–17%) of the rough and very rough seas distribute over some regions in the central SCS. Sea states from high to phenomenal conditions show rare occurrence(<12%) in the northern SCS. The calm(glassy) sea condition shows no occurrence in the SCS.

煤层气系统的定义、内涵、形成及应用——以鄂尔多斯盆地石炭系—二叠系煤层为例

煤层气在温度、压力和应力等敏感地质要素的作用控制下形成煤—气—水强耦合系统,深刻理解该系统对加快发展煤层气赋存地质理论、高效推进煤层气勘探开发具有重要意义。为此,提出了煤层气系统的基本概念,并在明确煤层气系统的基本要素基础上,研究了煤层气系统形成过程及基本特点,总结分析了煤层气系统储层压力、地层温度、地下水化学特征和煤层气的赋存状态、构成、含气饱和度以及生产特征,最后以鄂尔多斯盆地煤层气为例,分析了煤层气系统在空间上的展布规律。研究结果表明:①煤层气系统应考虑的基本要素包括煤层及其与之相关联的地层压力系数相近的煤系其他岩层、盖层系统以及相近地层压力系数下的煤层气/水流体系统。②储层—盖层—流体3大要素与系统环境演化的耦合决定了不同深度煤层气系统的煤—气—水的赋存状态。③以煤层气赋存状态等为主要依据将煤层气系统划分为“两带”,两带为改造带和原生带,其中改造带对应于通常意义上的浅层煤层气,原生带对应于深层煤层气;原生带进一步划分为吸附气为主带(原生A带)、游离气—吸附气带(原生B带)、吸附气—游离气带(原生C带)。结论认为:①改造带煤层气主要以向斜控气模式为主,原生带煤层气特别是原生B带、原生C带应重视圈闭区的勘探;②鄂尔多斯盆地石炭系—二叠系煤层气系统自东西两翼至中部由改造带—原生A带—原生B带—原生C带依次转变,盆地中部主要为原生B带及原生C带煤层气。

利用AMICS测试技术分析冶炼矿渣中Cu-Co元素的赋存状态

铜作为一种战略资源,是支撑经济社会发展的工业金属;钴在保障我国战略性新兴产业发展、保障国家能源资源安全方面有着非常重要的意义。采用矿物自动定量分析系统(AMICS)结合化学分析、化学物相、扫描电镜(SEM)及能谱仪(EDS)等多手段,系统地对某铜钴精矿冶炼渣进行工艺矿物学分析。在查明了矿渣的化学成分、组分组成、颗粒嵌布与结晶特征、粒度分布等关键信息的同时,对制约和影响其中Cu、Co元素提取利用的矿物学因素进行了分析。结果显示,经冶炼后的铜钴精矿渣组成现大多已不是矿物形态,而是由不同元素结合而成的“组分”;Cu元素的富集载体较多,主要以独立组分形式存在,而Co元素的赋存形式较为单一,且以类质同象替代形式为主。研究成果为矿渣的再利用提供理论参考依据,同时为同类型及相似类型的尾渣提供研究及利用思路。

南襄盆地泌阳凹陷古近系核桃园组页岩含油性及烃类赋存特征

南襄盆地泌阳凹陷古近系核桃园组发育优质湖相页岩层系,页岩油资源潜力巨大。前人针对该层系页岩含油性及烃类赋存状态的研究相对薄弱,可能是制约泌阳凹陷页岩油勘探突破的重要因素之一。以泌阳凹陷南部Y1井核三段Ⅲ亚段页岩为研究对象,通过岩石热解、多温阶热解、X射线衍射等地球化学分析技术,系统开展了页岩含油性、烃类赋存特征及影响因素研究。研究结果显示:核三段Ⅲ亚段页岩岩相组合主要包括长英质页岩相、云灰质页岩相和混合质页岩相,纹层结构发育。烃源岩类型整体处于好—优质范围,热演化程度处于生油阶段。有机显微组分以腐泥型为主,有机质类型为Ⅰ—Ⅱ1型。页岩含油性随埋深增大呈递增趋势,烃类赋存特征由中上部以吸附烃为主,过渡至下部以游离烃为主。碎屑矿物及有机碳含量是控制游离烃和吸附烃含量的主要因素。总体认为,核桃园组下部页岩含油饱和度指数整体高于100 mg/g,游离烃含量平均高于3 mg/g,具备较好的页岩油勘探开发前景。

湖北宜昌磷矿伴生稀土元素分布规律、赋存状态及其开发利用前景分析

【研究目的】湖北省宜昌磷矿中伴生有稀土元素,研究其分布规律及赋存状态,对稀土元素的回收利用具有重要意义,其作为伴生矿产的综合利用将成为未来稀土矿的重要来源。【研究方法】本文以含稀土磷块岩为主要研究对象,在系统取样的基础上,开展岩矿鉴定、全岩地球化学分析、XRD衍射分析、SEM观察、LA-ICP-MS测试等工作。【研究结果】磷块岩中稀土元素总量ΣREE+Y为63.5×10^(-6)~271.8×10^(-6),不同层位或不同岩性的磷块岩中稀土元素含量有所差异。【结论】稀土元素含量受岩性控制明显,由白云岩→白云质磷块岩→致密块状磷矿石→泥质条带磷块岩→泥岩,含量逐渐升高。微量元素反映出宜昌磷矿的古气候以干热为主,西北部略表现出温暖湿润特点;Ce异常、V/Ni和Y/Ho比值反映海水中EH条件从底部到顶部,即从Ph22成磷期到Ph13成磷期,形成水体环境逐渐氧化。宜昌磷矿中稀土元素总量整体较低,且泥岩较磷块岩中含量高,表明吸附态稀土较类质同象稀土含量高。宜昌伴生稀土磷矿资源丰富,利用合理的技术对稀土元素进行综合回收,对宜昌磷矿资源的合理利用和经济发展有重要意义。

贵州青山铅锌矿床中钒的赋存状态研究

钒属于战略性关键金属,其成矿作用研究备受关注。贵州省青山铅锌矿床隶属于川滇黔成矿域威宁-水城Pb-Zn-Ag成矿带,分为青山、横塘两个矿区,为中型铅锌矿床。初步研究表明,横塘矿区氧化矿带的矿石中钒异常富集,但其赋存状态未知。为此,本文利用电感耦合等离子体质谱(ICP-MS)、粉晶X射线衍射(XRD)和扫描电镜(SEM)等多种手段对该矿床的氧化铅锌矿石、蚀变白云岩和辉绿岩的矿物组合以及化学组成进行了系统分析。结果表明,氧化铅锌矿石、蚀变白云岩和辉绿岩中钒含量分别为11.9×10^(–6)~5 963×10^(–6)、168×10^(–6)和448×10^(–6)~701×10^(–6),相对于平均地壳其富集系数分别为20、1.2和4.1。氧化矿石和蚀变白云岩中的钒皆赋存在独立矿物(钒铅锌矿[Pb Zn(VO4)(OH)])中,而且钒铅锌矿中As含量较高,As以类质同象的形式替代V而进入钒铅锌矿中;蚀变辉绿岩中未发现钒的独立矿物,钒可能主要以类质同象的形式取代锐钛矿/金红石(Ti O2)中的Ti。此外,矿石中的V与Cu、Ni、Mo、Bi四种元素的相关性表明它们可能是共同沉淀进入矿石,有着相似的富集规律。氧化矿石的稀土和微量元素配分模式与蚀变白云岩比较接近,指示二者经历了相似的热液过程。钒是主要来自白云岩的交代淋滤还是与辉绿岩有关的岩浆热液有待进一步研究。本次研究表明铅锌矿床中钒以独立矿物和类质同象的形式分别存在于氧化矿石/蚀变白云岩和辉绿岩中,对铅锌矿石中钒的综合利用具有一定指示意义。

大宝山含钨褐铁矿中钨的赋存状态与嵌布特征

通过多种分析方法,探究广东大宝山含钨褐铁矿的物相组成、元素分布等工艺矿物学特征,以揭示矿石中关键金属钨的赋存状态与嵌布特征。X射线荧光分析(XRF)、粉末X射线衍射(XRD)以及扫描电子显微镜和能谱(SEM-EDS)结果表明:矿石中主要矿物为含钨褐铁矿和石英,关键金属钨品位为1.35%。微区X射线衍射(Micro-XRD)和矿物解离度分析仪(MLA)结果表明:钨主要赋存于高铁钨华((W,Fe)(O,OH)_(3))中,而高铁钨华则以剥离和带状形式紧密分布在褐铁矿中。同时,还定量分析了有价元素在各主要矿物中的赋存和分布情况,并讨论了含钨褐铁矿风化演变和形成机制。最终提出了一种选冶联合分选回收流程,为高效回收含钨褐铁矿中关键金属钨提供理论基础。

表生水土环境铊污染成因研究现状与发展趋势

铊(Tl)是一种有毒的重金属,对人类的危害超过了汞、镉、铅、锌、铜等传统致毒重金属元素。本文总结了铊的元素特征及其地球化学行为、含铊矿床的全球分布及其成矿时代,对比分析了铊在三大类岩石中的分布差异性,系统回顾了铊的毒理性及其致病机理、铊污染源解析与示踪、表生环境铊的迁移与转化。通过研究发现,铊在三大类岩石中均有分布,且岩浆岩中铊元素呈规律性分布。铊与热液矿床关联性强,主要富集于与低温热液矿床有关的铅、锌等矿床中,且优先进入硫化物熔体,致使含硫化物矿床铊浓度较高。总体而言,我国土壤铊污染与铊矿产分布均具有“南高北低”的特征,显示铊污染与铊矿床的开采和冶炼具有显著关联性。水体中铊主要以Tl^(+)进行迁移,Tl^(+)可替代K^(+)进入黏土矿物,或通过微生物作用氧化成Tl^(3+)。铊从土壤中通过植物根系进入植物体后,将不均匀地分布于植物体内,^(203)Tl更容易向细胞膜表面动态扩散,植物根系优先吸收较轻的铊同位素(^(203)Tl),较重的铊同位素(^(205)Tl)留于生长层。通过对比铅与铊同位素示踪法,发现铊同位素法对于示踪物质来源及其迁移过程具有响应速度快、敏感性强等优势,但铊同位素技术的提升还有待铊同位素数据库的进一步完善。铊污染形成演化时空模拟是揭示污染来源、污染过程与发展趋势以及开展区域风险评估的重要手段,但数据获取、模型选择与验证、不确定性分析以及系统集成与决策支持等问题均有待进一步加强研究。

低熔点亲铜元素(LMCE)在金成矿中的作用及促进金富集的机理

低熔点亲铜元素(LMCE),包含As、Sb、Bi、Hg、Pb、Se、Te、Tl、Sn等,在戈尔德斯密特(V·M·Goldschmidt)元素地球化学分类中均属于亲铜元素。它们具有亲铜性、电负性大、低熔点、半金属的特性。在金成矿过程中,这些元素与硫的亲和力强,多形成LMCE的硫化物、硫盐矿物、硒化物、碲化物和金属互化物,甚至形成LMCE与金的互化物和金的化合物。同时,它们在成矿流体中可以形成LMCE熔体,并对金矿床中Au的高效富集沉淀起到一种重要的桥梁作用。作者针对LMCE在金矿床中的赋存状态,总结了金矿床中LMCE富集金的特点,综合归纳了LMCE对金富集的成矿机理,认为在一些大型金矿床中,除了人们熟知的水-岩反应、硫化作用、流体沸腾、流体混合、有机成矿、岩浆脱气、叠加成矿等对热液金矿床的成矿起到重要作用外,流体-熔体分离、溶解-再沉淀、矿物重结晶、矿物表面吸附和元素替代等地质作用,也是LMCE在成矿过程中对金的富集重要机制。