新疆准噶尔北缘阿克希克铁金矿流体包裹体研究

阿克希克铁金矿床位于准噶尔北缘,矿体呈似层状、脉状、透镜状赋存于南明水组火山岩及凝灰岩的接触带上。围岩蚀变不发育,主要为硅化、绢云母化、绿泥石化、黄铁矿化、碳酸盐化等。矿床的形成经历了火山沉积期和热液期,铁矿化主要形成于火山沉积期,金矿化主要形成于热液期。火山沉积期石英以发育液体包裹体和少量含CO2包裹体为特征,热液期石英以发育含CO2和碳质(CH4和C4H6)包裹体为特征。火山沉积期成矿流体为中温(集中于180~320℃)、低盐度(集中于6~10 wt%Na Cleq)、中-低密度(0.59~0.98 g/cm3)的Na Cl-H2O-CO2体系。热液期成矿流体为中温(集中于220~320℃),低盐度(集中于2~10 wt%Na Cleq),中-低密度(0.55~1.03 g/cm3)的Na Cl-H2O-CO2-CH4型流体。火山沉积期石英的δDSMOW为-129.9‰^-97.9‰,δ18OSMOW值介于7.9‰~12.3‰,δ18OH2O值为-2.6‰~4.4‰,推测成矿流体为海水与岩浆水的混合。热液期石英的δDSMOW介于-129.8‰^-102.6‰,δ18OSMOW值介于11.2‰~16.1‰,δ18OH2O变化于3.1‰~7.4‰,推测成矿流体为变质水混合深循环的大气降水。结合矿床地质特征、流体成分和性质,本文认为热液期金矿化与CO2-CH4流体有关。

大崇铁金矿矿体分布特征及矿石加工技术性能研究

基于大崇铁金矿区域地质概况,研究了矿体分布特征,根据铁金矿体和极化率异常宽度的对应关系,圈定为2个铁金矿带,推断断裂构造1条,走向北西、倾向北东;分析了矿石加工技术性能,确定以综合回收磁铁矿和金为目的,推荐矿山采用“阶段磨矿-弱磁-磁选柱流程”。研究表明矿山开采铁、金矿具有较好的经济效益。

鲁西莱芜三岔河矽卡岩型铁金矿床岩体成因:锆石U-Pb年代学和岩石地球化学证据

【研究目的】莱芜三岔河矿床是鲁西地区首次发现的矽卡岩型铁金矿床(不含铜),以往研究相对薄弱,本文旨在对成矿岩体形成时代、源区性质、岩石成因和构造背景进行讨论。【研究方法】本文开展了LA-ICP-MS锆石U-Pb测年、岩体主微量测试工作。【研究结果】结果显示辉石闪长岩侵位年龄为(138.4±1.2)Ma,属早白垩世。辉石闪长岩里特曼指数σ=2.20~2.54,为钙碱性岩石;辉石闪长岩具高Mg~#、富Na特征,Sc、Cr、Co、Ni含量较高,表明其具有幔源岩浆的属性;富集轻稀土元素(LREE),亏损重稀土元素(HREE),Eu异常不明显,富集大离子亲石元素(Cs、Ba、Sr),亏损高场强元素(Nb、Ta、Zr),暗示有地壳物质的涉入。【研究结论】三岔河辉石闪长岩可能起源于受华北克拉通古老地壳物质改造的富集岩石圈地幔的部分熔融,形成于岩石圈减薄的强烈伸展构造背景,可能与太平洋板块俯冲后撤引起的伸展构造环境有关。

提高青海某铁金矿金浮选回收率的研究与实践

针对青海某铁金矿金浮选回收率偏低(仅有80%)的问题开展了系统研究,发现磨矿粒度偏粗是原来生产金浮选回收率低的关键原因。通过试验确定适宜的磨矿粒度为-0.074 mm粒级占80.40%,该磨矿粒度下采用一粗-两精-两扫的浮选工艺流程,闭路试验获得了精矿金品位93.86 g/t、回收率87.96%的良好指标。现场改造在基本不改变浮选工艺流程及药剂制度情况下,仅降低磨矿粒度,取得了明显的效果,金回收率提高到87.5%。

莱芜三岔河铁金矿床的发现及其特征

莱芜三岔河矿床为矽卡岩型铁金共生矿床,伴生银和硫。三岔河及周边地区前期勘查多以铁矿为主,矿体规模较小,未取得显著成果。近期在铁矿勘查中,发现部分样品金达到工业品位,经反复研究后调整工作思路,将勘查目标确定为铁金综合评价,实现了找矿突破。矿床为中型规模,矿体赋存于燕山晚期黑云母闪长岩内的奥陶纪地层灰岩捕掳体附近,矿体形态产状较稳定,呈似层状、透镜状,严格受接触带控制。莱芜三岔河矽卡岩型铁金矿床是鲁西地区找矿新发现,对鲁西地区寻找共生金矿具有指导意义。

安徽巢湖马家凹铁金矿化特征与找矿前景

马家凹矿区区域上位于郯庐断裂带内,矿区出露地层为浮槎山岩组、大横山岩组、双山岩组、西冷岩组以及第四系,岩浆岩发育,构造变形强烈,主要构造变形为韧性剪切带,呈北东向展布。文章通过分析区域地质背景和矿区地质特征,结合钻探和槽探采集样品并分析结果,研究发现马家凹矿区铁矿化带3条,金银矿化带3条,因此该区具有良好的铁金找矿前景。

陕西省洛南地区铁金矿地质特征及找矿前景

该矿区位于华北地矿南缘,矿区出露地层为中元古界长城系上熊耳群,以块状细碧岩为主,夹杏仁状细碧岩、泥砂质板岩、凝灰质板。分为上熊耳群中段、上熊耳群下段。翻山沟铁矿为熊耳群火山沉积作用、区域变质作用与后期构造热液复合叠加形成的铁矿床。

莱芜市三岔河铁金矿矿石质量特征

三岔河矿区发现的金矿是产于黑云母闪长岩内奥陶系地层捕掳体附近的中型金矿床,是山东境内目前发现的规模较大的矽卡岩型金矿床。位于华北板块鲁西隆起区鲁中隆起,新甫山—莱芜断隆泰莱凹陷的东南部,本文旨在介绍莱芜市三岔河金矿的矿石质量特征。

新疆若羌县沟口泉铁金矿地质特征及矿床成因探讨

新疆若羌县沟口泉铁金矿大地构造位于阿尔金古陆块和红柳沟-拉配泉奥陶纪裂谷,构造复杂,岩浆岩发育。矿体产于奥陶系中上统拉配泉群(O_(2-3)L)的凝灰质粉砂岩中。对比同一成矿带典型铁金矿地质特征及矿床成因,认为铁矿床成因类型属沉积浅变质型铁矿,金矿床属破碎蚀变石英细网脉型金矿。

北衙铁金矿水文地质条件再认识

北衙铁金矿是云南省最大的黄金矿山,属中国十大金矿之一。矿山自2007年4月规模化露天开采以来,已经形成坑口面积约2.04 km^(2),最低开采标高1 540m,最大采深384 m的深凹露天采坑。矿坑直接充水含水层为岩溶含水层,现露天采坑外边界500 m范围内有流量极大的岩溶大泉及地表河流,露天采坑位于地下水径流途径上,但露天采坑涌水量不大,岩溶大泉及地表河流的补给作用不明显。矿山开采实际掘露的矿区水文地质条件与前期多轮地质勘查工作结论差异较大。未来深部露天最低开采标高将延伸至1 385 m,最大采深达539 m并逐渐露转坑开采,对矿区水文地质条件的正确认识显得尤为重要,该文根据矿山实际生产揭示的水文地质现象,对矿区水文地质条件进行了再认识,希望能对矿山水文地质专项补充勘查和今后深部露天及露转坑生产的防排水设计提供借鉴。

Effects of Ti-and Mg-bearing minerals on hydrothermal formation of hydroandradite

The effects of Ti-and Mg-bearing minerals on the crystal structure,morphology,particle size distribution,and formation mechanism of efficient desilication product of hydroandradite(HA)during hydrothermal conversion in a synthetic sodium aluminate solution were investigated via X-ray diffractometer,scanning electron microscope and particle size analyzer.During HA formation,anatase,rutile,and periclase dissolved in sodium aluminate solution engage in ion substitution reactions between Ti4+and Si4+,and between Mg^(2+)and Ca^(2+),respectively.However,dissolved hydromagnesite cannot enter into the HA.The content of HA after the hydrothermal reactions changes slightly with the increase of anatase and periclase contents,but it notably decreases with increased quantities of rutile and hydromagnesite.Ti-bearing minerals reduce the particle size and enhance the specific surface area of HA,whereas Mg-bearing minerals exert the opposite effect.The morphology of HA with Ti-and Mg-bearing minerals changes from spherical particles to flocculent structure and hexagonal plate-like particles.

Mineral cleavage nature and surface energy: Anisotropic surface broken bonds consideration

The population of surface broken bonds of some typical sulfide, oxide and salt-type minerals which may belong to cubic, tetragonal, hexagonal, or orthorhombic system, were calculated. In terms of the calculation results, the cleavage natures of these minerals were analyzed, and the relationship between surface broken bonds density and surface energy was also established. The results show that the surface broken bonds properties could be used to predict the cleavage nature of most of minerals, and the predicted cleavage planes agree well with those reported in previous literature. Moreover, this work explored a rule that, surface broken bonds density is directly related to surface energy with determination coefficient（R2） of over 0.8, indicating that the former is a dominant factor to determine the latter. Therefore, anisotropic surface broken bonds density can be used to predict the stability of mineral surface and the reactivity of surface atoms.

Effect of arsenopyrite on thiosulfate leaching of gold

Arsenopyrite was artificially added into the thiosulfate leaching solution to clarify the role of arsenopyrite on the thiosulfate leaching of gold.The effect of arsenopyrite on the thiosulfate leaching of gold was studied by the thermodynamic calculation,mineral dissolution test,leaching test and XPS analysis.The results show that the thiosulfate consumption slightly increases with increasing the concentration of arsenopyrite,but the gold dissolution is obviously hindered.This may mainly attribute to the catalytic effect of arsenopyrite on the thiosulfate decomposition and the formation of passivation layer on the gold foil surface.The passivation layer likely consists of Cu2S or Cu（S2O3）35-,element S,FeOOH and iron arsenate,which is deduced from the XPS analysis.However,the negative effect of arsenopyrite can be eliminated by adding additives.It is found that both additives of sodium carboxymethyl（CMC） and sodium phosphate（SHPP） can not only decrease the thiosulfate consumption but also improve the gold dissolution.

Leaching kinetics of gold bearing pyrite in H_2SO_4-Fe_2(SO_4)_3 system

Gold bearing pyrite leaching was conducted in H2SO4-Fe2（SO4）3 system at different reaction temperatures,with different ferric ion concentrations,sulfuric acid concentrations and stirring speeds.The leaching kinetics and mechanism were studied.When the temperature ranged between 30-75 °C,the pyrite leaching was mainly controlled by chemical reaction with positive correlation to the ferric ion concentration.The activation energy obtained from Arrhenius empirical formula is 51.39 k J/mol.The EDS and XPS analyses suggest that the oxidation of sulfur within pyrite is through a series of intermediate stages,and eventually is oxidized to sulphate accompanied with the formation of element sulfur.This indicates a thiosulfate oxidation pathway of the gold bearing pyrite oxidation in H2SO4-Fe2（SO4）3 system.

An intelligent system for calculating the scale of rational,enlarged production of an underground non-ferrous metal mine

The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of artificial intelligence.Based on the analysis of the major factors affecting the scale of enlarged production,we first interpreted in detail the design principles and structure of the intelligent system.Secondly,we introduced an ANN subsystem.In order to ensure technological and scale efficien- cies of the training samples for ANN,we filtrated the samples with a DEA method.Finally,we trained the intelligent system,which was proved to be very efficient.

Magnetic Properties as Indicators of Cu and Zn Contamination in Soils

Concentrations of copper （Cu） and zinc （Zn） and various magnetic parameters in contaminated urban roadside soils were investigated using chemical analysis and magnetic measurements. The results revealed highly elevated Cu and Zn concentrations as well as magnetic susceptibility in the roadside soils. The mean concentrations of Cu and Zn in these roadside soils were almost twice those in average Chinese soils, with the mean magnetic susceptibility of the roadside soils reaching about 179 ×10^-8 m^3 kg^-1. This enhanced magnetic susceptibility was attributed to the presence of anthropogenic soft ferrimagnetic particles. A low frequency-dependent susceptibility （2.5%± 1.0%） observed in the roadside soils indicated the coarse multidomain （MD） ferrimagnetic grains to be the dominant contributor to magnetic susceptibility. The Cu and Zn concentration of the soils had highly significant linear correlations with magnetic susceptibility （P 〈 0.01）, anhysteretic remanent magnetization （P 〈 0.01）, and saturation isothermal remanent magnetization （P 〈 0.01）. This suggested that heavy metals were associated with ferrimagnetic particles in soils, which were attributed to input of traffic emissions and industrial activities. Scanning electron microscopy and energy dispersive X-ray spectra of magnetic extracts of the roadside soils further suggested the llnk between the magnetic signal and concentrations of heavy metals. Thus, the magnetic parameters could provide a proxy measure for the level of heavy metal contamination and could be a potential tool for the detection and mapping of contaminated soils.

Fe/Co and Ni/Co-pentlandite type electrocatalysts for the hydrogen evolution reaction

Metal-rich transition metal sulfides recently gained increasing attention as electrocatalysts for the hydrogen evolution reaction(HER),as they are capable to overcome major challenges faced by sulfide-rich metal catalysts such as limited conductivity and the necessity of nanostructuring.Herein,we present the synthesis,characterization and electrocatalytic investigation of ternary metal-rich sulfide composites FexCo9-xS8 as well as Ni_(y)Co_(9-y)S_(8)(x=y=0-4.5),which possess pentlandite-type structures.In this study,we show a stepwise alteration of the binary cobalt pentlandite Co9S8 and report on the replacement of cobalt with up to 4.5 equivalents of either iron or nickel.These altered pentlandite composites facilitate the proton reduction in acidic media at different temperatures.We furthermore show that the stoichiometric variation has a decisive influence on the electrochemical activation/deactivation behavior of the catalysts under reductive electrocatalytic conditions.Here,Co-deficient composites display an improved HER performance in contrast to Co_(9)S_(8).Notably,Ni/Co compounds generally tend to show higher catalytic activities towards HER than their respective Fe/Co compounds.

Combined Chemical and Mineralogical Evidence for Heavy Metal Binding in Mining- and Smelting-Affected Alluvial Soils

The binding of metallic contaminants （Pb, Cd, and Zn） and As on soil constituents was studied on four highly contaxninated alluvial soil profiles from the mining/smelting district of Pribram （Czech Republic） using a combination of mineralogical and chemical methods. Sequential extraction analysis （SEA） was supplemented by mineralogical investigation of both bulk samples and heavy mineral fractions using X-ray diffraction analysis （XRD） and scanning electron microscopy with an energy dispersive X-ray spectrometer （SEM/EDS）. The mineralogy of Fe and Mn oxides was studied by voltammetry of microparticles （VMP） and diffuse reflectance spectrometry （DRS）. Zinc and Pb were predominantly bound in the reducible fraction attributed to Fe oxides and Mn oxides （mainly birnessite, Na4Mn14O27.9H2O）, which were detected in soils by XRD and SEM/EDS. In contrast, Cd was the most mobile contaminant and was predominantly present in the exchangeable fraction. Arsenic was bound to the residual and reducible fractions （corresponding to Fe oxides or to unidentified Fe-Pb arsenates）. SEM/EDS observations indicate the predominant affinity of Pb for Mn oxides, and to a lesser extent, for Fe oxides. Thus, a more suitable SEA procedure should be used for these mining-affected soils to distinguish between the contaminant fraction bound to Mn oxides and Fe oxides.

Mobility of Arsenic and Heavy Metals in a Sandy-Loam Textured and Carbonated Soil

The continued effect of the pyrite-tailing oxidation on the mobility of arsenic, lead, zinc, cadmium, and copper was studied in a carbonated soil under natural conditions, with the experimental plot preserved with a layer of tailing covering the soil during three years. The experimental area is located in Southern Spain and was affected by a pyrite-mine spill. The climate in the area is typically Mediterranean, which determines the rate of soil alteration and element mobility. The intense alteration processes that occurred in the soil during three years caused important changes in its morphology and a strong degradation of the main soil properties. In this period, lead concentrated in the first 5 mm of the soil, with concentrations higher than 1500 mg kg?1, mainly associated to the neoformation of plumbojarosite. Arsenic was partially leached from the first 5 mm and mainly concentrated between 5–10 mm in the soil, with maximum values of 1239 mg kg-1; the retention of arsenates was related to the neoformation of iron hydroxysulfates (jarosite, schwertmannite) and oxyhydroxides (goethite, ferrihydrite), both with a variable degree of crystallinity. The mobility of Zn, Cd, and Cu was highly affected by pH, producing a stronger leaching in depth; their retention was related to the forms of precipitated aluminium and, in the case of Cu, also to the neoformation of hydroxysulfate.

Effect of pyroxenite and olivine minerals as source of MgO in hematite pellet on improvement of metallurgical properties

Pelletization of hematite ore requires high fineness and very high induration temperature（~1325 ℃） owing to its poor diffusion bonding unlike magnetite ore. Further, high-alumina hematite pellets show very high reduction degradation index（RDI） during low temperature（500-650 ℃） reduction due to their volume expansion and lattice distortion. Noamundi（India） hematite ore contains very high Al2O3（2.3%） with adverse ratio of alumina to silica（~2） for which, it shows very high RDI. In this work, the acid pellets prepared from Noamundi ore fines of optimum Blaine fineness show good cold crushing strength（CCS）. However, it shows very high RDI（77%）. In order to reduce RDI, Mg O in form of two different gangue-containing fluxes, such as pyroxenite and olivine in varying quantities has been added. The optimum requirement and performance of these fluxes has been examined and compared. Both pyroxenite and olivine fluxed pellets show significant lowering of RDI（26% and 23%, respectively） and improvement of other properties, viz CCS, swelling indices etc with good reducibility（70%-77%）. Finally, a good quality acidic hematite pellet was developed from high-alumina ore without using any lime which is very important charge material in combination of basic sinter in blast furnace.