Effects of galvanic interaction between galena and pyrite on their flotation in the presence of butyl xanthate

The effects of galvanic interaction between galena and pyrite on their flotation and electrochemical characters were studied by electrochemical,adsorption,flotation and FTIR techniques,respectively.Electrochemical tests indicate that galena is electrochemically more active than pyrite and serves as an anode in galvanic combination with pyrite.The galvanic current density from a mixture of galena and pyrite is 4 times as high as the self corrosion current density of galena,which indicates that the corrosion rate of galena is accelerated.Adsorption tests show that the adsorption of butyl xanthate on galena surface is enhanced,and affected by a combination of pyrite-galena mixtures and conditioning time.Compared with individual mineral particles,galvanic interaction reduces the floatability difference between galena and pyrite.The flotation recovery of galena decreases while that of pyrite increases when two minerals are mixed together due to the influence of galvanic interaction on the formation of hydrophilic/hydrophobic product.The FTIR results show that the formation of dixanthogen on pyrite surface is depressed due to the galvanic interaction.

Mechanism of sodium sulfide on flotation of cyanide-depressed pyrite

The mechanism of sodium sulfide(Na2S)on the flotation of cyanide-depressed pyrite using potassium amyl xanthate(PAX)as collector was investigated by flotation test and electrochemical measurements.The flotation results show that both PAX and Na2S can promote the flotation recovery of cyanide-depressed pyrite and their combination can further improve the pyrite flotation recovery.Electrochemical measurements show that PAX and Na2S interacted with cyanide-depressed pyrite through different mechanisms.PAX competed with cyanide and was adsorbed on the pyrite surface in the form of dixanthogen,thus enhancing the hydrophobicity and flotation of cyanide-depressed pyrite.Unlike PAX,Na2S rendered the pyrite surface hydrophobic through the reduction of ferricyanide species and the formation of elemental sulfur S0 and polysulfide Sn2-.The combined application of PAX and Na2S induced superior pyrite flotation recovery because of a synergistic effect between PAX and Na2S.

Flotation and surface modification characteristics of galena,sphalerite and pyrite in collecting-depressing-reactivating system

The flotation tests and XPS analyses on galena,sphalerite and pyrite have been carried out in a collecting-depressing-reactivating system(hereafter referred as the CDR system).In this system,sulfide minerals were first collected and activated by the collector,and then depressed strongly by Ca(OH)2 in the strong alkaline solution,and finally reactivated by H2SO4.The flotation tests of pure minerals show that in this system the flotation behaviors of sphalerite and pyrite present irreversible characteristics along with the change of pulp potential.Furthermore,through the CDR system,considerable differences in the flotabilities between galena and sphalerite/pyrite are also observed.The XPS analysis results for galena,sphalerite and pyrite in a CDR system show that in the strong alkaline solution,some of the collectors,that have been already adsorbed on the mineral surface in the collecting process,are desorbed by Ca(OH)2.The XPS analysis results also show that in H2SO4 reactivating process,the surface hydroxides of galena are desorbed again by H2SO4 and replaced by diethyl dithiocarbamate,but those of sphalerite and pyrite are not desorbed.This flotation system may be applied to the bulk-differential flotation process of sulfur-bearing low-grade lead-zinc ores.

Ore-forming mechanism of Huxu Au-dominated polymetallic deposit in the Dongxiang Basin,South China:Constraints from in-situ trace elements and S-Pb isotopes of pyrite

The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry,while the genesis of this deposit is unclear.This study focused on geological and mineralogical characteristics,in-situ trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite,ore-forming fluid and material sources,and genetic types of the deposit.The mineralization stage of the deposit can be divided into quartz-pyrite stage(S1),quartz-pyrite-hematite stage(S2),quartz-polymetallic sulfide stage(S3)and quartz-hematite stage(S4),with the corresponding pyrite being divided into three generations(Py1-Py3).in-situ trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution(Au^(+)),and the content is relatively low at all stages(0.18 ppm for Py1,0.32 ppm for Py2,0.68 ppm for Py3),while Pb and Zn mainly exist as sulfide inclusions in the pyrite.S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma.The mineral association,mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4,respectively,while water-rock interaction controlled the precipitation of Pb-Zn sulfides.These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.

Genesis of Strata-bound Sulfide Orebodies in the Tongling Polymetallic Mineralization Cluster, SE China: Evidence from Colloform Pyrite

Colloform pyrite(CPy)is widely distributed in the Tongling mineralization cluster of the Middle-Lower Yangtze River Mineralization Belt(MLYRMB),China.There have many debates as to whether such CPy is associated with Late Mesozoic igneous or Carboniferous sedimentation.CPy from the Xinqiao deposit,a representative of the stratabound sulfide deposits in the MLYRMB,was studied by powder X-ray diffraction(XRD),field-emission scanning electron microscopy(SEM),and high-resolution transmission electron microscopy(TEM).The results show that CPy mainly comprises pyrite,pyrrhotite,quartz,and illite.Pyrite in CPy shows cubic,globule,and xenomorphic morphologies.No octahedral or pyritohedron was observed.Most of the quartz crystals display xenomorphic morphology,where pyrite mold are popular on the surface.Organic matter(OM),which is usually bound to illite,is an important component in CPy.Morphological investigations which exhibit detrital features of quartz and clay minerals indicate that they were derived from continental weathering.Specially,some hexagonal pyrrhotite nanoparticles which show mackinawite morphology are coexisted with OM.The results indicate that the transformation process of sulfides possibly is mackinawite(the precursor)—hexagonal pyrrhotite-pyrite.Thus,compositional and micro-textural characteristics of CPy in Xinqiao deposit suggest it to be a sedimentary origin rather than a hydrothermal origin which is associated with Yanshanian magmatism.Moreover,the coexistence of CPy and stratabound sulfide orebodies in the MLYRMB suggests a causal link between the two.It is considered that CPy might have served as a Cu mineralization geochemical barrier for the Cu-bearing ore-forming fluids,which originated from the Mesozoic magma in the MLYRMB.

Electrochemical characteristics of couple electrode of galena-pyrite in different solutions

Cyclic voltammogram was used to study the electrochemical properties of the couple electrode of galena pyrite in xanthate and diethyldithiocarbamate (DDTC) solutions. When galena connects with pyrite, there exists galvanic interaction between two minerals. Because pyrite is nobler than galena, the anode oxidation of collector on the surface of galena is improved, and the anode oxidation of reagent on the surface of pyrite is weaken. The experimental results showed that it is difficult for the dixanthogen and (DDTC) 2 to be adsorbed on the surface of pyrite under galvanic interactions with galena.

Galvanic interaction between galena and pyrite in an open system

Galvanic interactions between sulfide minerals have very important influences on hydrometallurgical processes, the supergene enrichment of sulfides and the formation of acid mine drainage. By changing the concentrations of Fe+{3+}, the pH values, status of the flowing of the solution and the solution salinity (e.g. the concentrations of Na-2SO-4) and monitoring the galvanic currents and potentials, studies were conducted in this work on the galvanic interaction between pyrite acting as the anode and galena acting as the cathode. The results indicated that the concentrations of Fe+{3+}, pH values and the flowing of the solution exhibit a great effect on the galvanic interaction of galena-pyrite couple, while the salinity of the solution has only a slight influence on the interaction. The experiments also revealed that in case cracks exist on the surface of pyrite electrode, the potential of pyrite will decrease so sharply as to be lower than that of galena under the same experimental condition. The experimental results were explained in terms of the Butler-Volume equation and the theory of mixed potential.

Yolk shell-structured pyrite-type cobalt sulfide grafted by nitrogen-doped carbon-needles with enhanced electrical conductivity for oxygen electrocatalysis

Pyrite-type sulfides(PTS)exhibit promising intrinsic activities for oxygen reduction and evolution reactions(ORR/OER).However,their poor electrical conductivities may limit the charge transfer rate to inevitably lower activity.Here,yolk-shell structured cobalt-pyrite nanospheres(CoS_(2)YSS)are prepared and modified with amino groups as nucleation sites for coupling highly-conductive needle-like nitrogendoped carbon via a facile solvothermal method(CoS_(2)YSS@NC).The as-marked CoS_(2)YSS@NC-0.5 shows a gap between yolk and shell,and an obvious exterior layer of grafted NC,which can provide an integrated structure,an interior place,and three exposed surfaces on CoS_(2).CoS_(2)YSS@NC-0.5 reveals higher ORR activity(half-wave potential of 0.88 V)and methanol resistance than commercial Pt/C.Due to in-situ formation of highly-active CoOOH,CoS_(2)YSS@NC-0.5 shows a better overpotential(244 mV at 10 mA/cm^(2))and Tafel slope(135 mV/dec)than RuO2.Zinc-air battery with CoS_(2)YSS@NC-0.5 air-cathode exhibits good open circuit potential(1.44 V),specific capacity(772.5 mAh/g)and cycling stability.Needle-like NC layer coated on the yolk-shell structure of CoS_(2)effectively lowers the charge transfer resistance to obtain extraordinary ORR/OER activities.It indicates that the integration of highly-conductive carbon onto pyritetype sulfides is an effective strategy to acquire durable bifunctional ORR/OER catalysts.

Trace Elements and Rare Earth Elements of Sulfide Minerals in the Tianqiao Pb-Zn Ore Deposit,Guizhou Province,China

Trace elements and rare earth elements（REE） of the sulfide minerals were determined by inductively-coupled plasma mass spectrometry.The results indicate that V,Cu,Sn,Ga,Cd,In,and Se are concentrated in sphalerite,Sb,As,Ge,and Tl are concentrated in galena,and almost all trace elements in pyrite are low.The Ga and Cd contents in the light-yellow sphalerites are higher than that in the brown and the black sphalerites.The contents of Ge,Tl,In,and Se in brown sphalerites are higher than that in light-yellow sphalerites and black sphalerites.It shows that REE concentrations are higher in pyrite than in sphalerite,and galena.In sphalerites,the REE concentration decreases from light-yellow sphalerites,brown sphalerites,to black sphalerites.The ratios of Ga/In are more than 10, and Co/Ni are less than 1 in the studied sphalerites and pyrites,respectively,indicating that the genesis of the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis associated with hydrothermal genesis.The relationship between LnGa and LnIn in sphalerite,and between LnBi and LnSb in galena,indicates that the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis.Based on the chondrite-normalized REE patterns,δEu is a negative anomaly（0.13-0.88）,andδCe does not show obvious anomaly（0.88-1.31）;all the samples have low total REE concentrations（〈3 ppm） and a wide range of light rare earth element/high rare earth element ratios（1.12-12.35）.These results indicate that the ore-forming fluids occur under a reducing environment.Comparison REE compositions and parameters of sphalerites,galenas,pyrites,ores,altered dolostone rocks,strata carbonates,and the pyrite from Lower Carboniferous Datang Formation showed that the ore-forming fluids might come from polycomponent systems,that is,different chronostratigraphic units could make an important contribution to the ore-forming fluids.Combined with the tectonic setting and previous isotopic geochemistry evidence,we conclude that the ore-deposit genesis is hydrothermal,sedimentary reformed,with multisources characteristics of ore-forming fluids.

GALVANIC INTERACTION OF CONTACTING SULFIDE PARTICLE AND ITS EFFECT ON FLOTATION

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Iron Monosulfide Distribution in Three Coastal Floodplain Acid Sulfate Soils, Eastern Australia

The distribution of iron monosulfide (quantified as acid volatile sulfur: SAV) was compared with geo- chemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp, McLeods Creek and Bungawalbyn Swamp respectively. These properties included PH, reactive iron (FeR), pore-water sulfate (SO:42-) and organic carbon (OC). Iron monosulfide was concentrated at the oxic/anoxic boundary. The Tuckean Swamp and McLeods Creek sites are Holocene sediments, whereas the Bungawalbyn Swamp is a Holocene peat. The concentration of SAV averaged 0.2 g kg-l in a 0.5 m thick soil layer at the Tuckean Swamp, but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp. The SAV mineral greigite (Fe3S4) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis (SEM-EDX). Very small concentrations of greigite were also observed in the McLeods Creek, based on crystal morphology and elemental composition. The concentration of SAV was a small fraction of the total reduced sulfur, representing at most 3% of the Pyrite sulfur. However, the presence of this highly reactive sulfide mineral, distributed within pores where oxygen diffusion is most rapid, has important implications to the potential rate of acid production from these sediments.

Microcalorimetric studies of interaction between extracellular polymeric substance and sulfide minerals

细胞外的聚合物质(EPS ) 似乎为 bioleaching 重要。为这些进程的更好的控制，沥滤的 EPS 的函数细菌具有关键重要性。Microcalorimetric 测量被用来学习 EPS 的三个模拟部件。L 半胱氨酸的附件与它的增加的集中增加，它是兰米尔单分子的层吸附。黄铁矿上的葡萄糖的附件类似于甘露糖，它不是兰米尔单分子的层但是多层的吸附。结果证明 EPS 调停附件并且与硫醚表面反应并且导致矿物质表面的改变的化学性质。学习在 EPS 和硫化物矿物质之间的相互作用提供一个新方法。

Z-200作捕收剂时无机调整剂加药顺序对铜铅锌硫化矿物浮选的影响

研究了在Z-200捕收剂体系下无机调整剂硫酸锌、硫酸铜、亚硫酸钠和硫化钠及其加药顺序对黄铜矿、方铅矿和闪锌矿浮选的影响。结果表明,与调整剂先于Z-200添加时相比,调整剂后于Z-200添加时,对3种硫化矿物的浮选有不同程度的影响:硫酸锌对黄铜矿尤其是方铅矿的抑制作用明显减弱,对闪锌矿在较低用量时抑制作用减弱,而在较高用量时则抑制作用更强;硫酸铜略微增强了对黄铜矿的抑制作用,对方铅矿有较强的活化作用,特别是较低用量时活化作用更强,对闪锌矿在较低用量时活化作用显著增强,而较高用量时则活化作用减弱;亚硫酸钠减弱了对黄铜矿特别是方铅矿的抑制作用,增强了对闪锌矿的抑制作用;硫化钠减弱了对黄铜矿的抑制作用,对方铅矿在较低用量时活化作用相当,而在较高用量时则抑制作用增强,较低用量时对闪锌矿的抑制作用增强。研究结果可为Z-200捕收剂体系下硫化矿浮选分离时无机抑制剂的选择及添加顺序提供参考。

云南某低品位斑岩型铜矿浮选回收试验研究

云南某大型斑岩型铜矿铜品位0.32%,伴生有钼,具有综合回收价值。采用一次粗选、两次精选、两次扫选工艺流程综合回收矿石中的铜和钼等金属。系统研究工艺参数条件如原矿磨矿细度、粗精矿再磨细度、捕收剂、抑制剂、起泡剂种类及用量等对铜回收的影响,并考察伴生金属钼、金和银的回收情况。结果表明,捕收剂PL307和起泡剂HCLL对铜浮选回收效果好,在原矿磨矿细度-0.075mm占比65%、粗精矿再磨细度-0.045mm占比90%、捕收剂PL-307用量120g/t、抑制剂石灰用量300g/t、起泡剂HCLL用量20g/t的最佳参数条件下,经过闭路试验可获得产率1.23%、铜品位22.84%、铜回收率87.79%的选矿指标,铜精矿产品含钼0.398%、金4.33g/t、银62.50g/,其中钼回收率为71.99%、金回收率为66.57%、银回收率为14.48%,伴生金属钼和金也得到了较好的回收,选别指标好。

Textures, trace element compositions, and sulfur isotopes of pyrite from the Honghai volcanogenic massive sulfide deposit:Implications for ore genesis and mineral exploration

In this paper, we present textures, trace element compositions, and sulfur isotope data for pyrite from the Honghai volcanogenic massive sulfide deposit to place new constraints on the source and evolution of the ore-forming fluids and provide insights into the ore genesis with implications for future exploration. The Honghai deposit consists of upper lenticular ores comprising massive sulfides that are underlain by stockwork and disseminated sulfides. The textural and isotopic characteristics of the synsedimentary framboidal pyrite(Syn-Py) indicate its formation by biogenetic processes. Coarse-grained pyrite generations(M-Py1, M-Py2, and M-Py3) from the massive sulfides have high Au, Ag, Cu, Zn, Pb, Sb, and Tl concentrations and low Co, Se, Te, Ti, and Sn concentrations, indicating that they precipitated from metal-rich, low-to intermediate-temperature,oxidizing fluids. The high Te, Ti, and Sn concentrations and high Co/Ni ratios in the massive pyrite(M-Py4) associated with magnetite in the massive sulfide lenses, as well as the high Ti, V, Cr, and Ni concentrations and low Al, Mn, and Zn concentrations in the magnetite, suggest that the coexisting M-Py4 and magnetite precipitated under oxidizing and hightemperature(300℃ to 500℃) conditions. In contrast, pyrite grains from the underlying stockwork and veins(V-Py1, V-Py2, and V-Py3) are characterized by low Au, Ag, Cu, Zn, Pb, Sb, and Tl concentrations coupled with high Co, Se, Te, and Ti concentrations and high Co/Ni ratios, which are interpreted in terms of reducing and high-temperature ore-forming fluids. The large variations in δ^(34)S values from-6.4‰ to +29.9‰ suggest that the ore-forming fluids were derived from magmatic source that were significantly modified by seawater. The spatial variations of trace element assemblages of pyrite from different levels of the main massive orebodies can be used as an indicator for mineral exploration of Cu-Zn ores in the Honghai deposit.Although no significant difference in δ34S values is observed between the upper massive sulfide lenses and lower stockwork/vein zone, the spiky δ34S pattern noted in the massive pyrite can be used as a marker for the main massive orebodies.

硫化矿物的浮选电化学与浮选行为

研究黄铜矿、黄铁矿、方铅矿等矿物在有/无捕收剂两种情况下的浮选行为,考察浮选与矿浆电位的关系。结果表明：当pH值分别小于4.0时,黄铜矿无捕收剂浮选的电位区间为0~0.9 V;当pH值为4.0或11.0时,矿浆电位大于0.85 V以后,黄铁矿的浮选回收率低于20%;当pH值为11.0时,黄铜矿无捕收剂浮选的矿浆电位区间为0.35~0.85 V。当pH值为10.0、丁黄药浓度为5×10-5 mol/L时,方铅矿浮选的矿浆电位为0.45~0.55 V,而黄铜矿在0.45~0.80 V的电位区间具有良好的浮选性能;对闪锌矿而言,当pH值为9.0时,矿浆电位在-0.40~0.80 V区间都不具有良好的可浮性。在浮选体系中,黄铜矿表面氧化会产生元素S0,当矿浆电位从-0.2V增大至0.6 V,黄铜矿表面氧化产生的元素S的数量逐渐增大,黄铜矿的无捕收剂浮选性能越来越好。从南京和青海2个铅锌矿山的应用情况来看,采用电位调控浮选技术可以大幅度缩短铅矿石的浮选时间,减少浮选机数量。例如在南京某铅锌矿,由于采用电位调控浮选技术,原来2个系列每天处理900 t矿石,现在采用一个系列即可处理。

新型有机抑制剂RC对黄铁矿和磁黄铁矿的抑制作用研究

研究了有机抑制剂RC对黄铁矿、磁黄铁矿的抑制作用。实验结果表明 ,RC对黄铁矿和磁黄铁矿均有较强的抑制作用。红外吸收光谱证明 :RC分子结构中含有—COO- 、—SO3- 、—OH等多种官能团 ,黄药与RC之间存在一种竞争吸附的关系 ,在pH为10的环境中 ,吸附对RC有利 ,由于RC携带众多的亲水集团 ,使得矿物表面更易亲水 ,进而抑制矿物。

氧分子在黄铁矿和方铅矿表面的吸附

采用密度泛函理论对氧分子在黄铁矿和方铅矿表面的吸附进行研究。计算结果表明:黄铁矿和方铅矿表面经历了较小的弛豫;氧分子在黄铁矿和方铅矿表面都呈解离吸附状态,且在黄铁矿表面的吸附能远低于在方铅矿表面的吸附能;在黄铁矿表面上,氧原子分别与铁原子和硫原子键合,电子由铁原子和硫原子转移到氧原子上,主要由硫的3p态、氧的2p态和铁的3d态参与反应,铁与氧之间形成d→p反馈键,而在方铅矿表面上,氧原子只与硫原子键合,主要由硫的3p态、氧的2p态和铅的6p态参与反应,未形成反馈键;氧吸附后黄铁矿表面产生键合的铁原子和氧原子都产生自旋现象,而方铅矿表面原子及吸附的氧原子仍然是低自旋态的。

Nocardia在黄铁矿和方铅矿表面的选择性吸附

研究了Nocardia在不同影响因素条件下在黄铁矿和方铅矿表面的选择性吸附.结果表明:Nocardia在黄铁矿和方铅矿表面可发生明显的选择性吸附,在黄铁矿表面的最大吸附率为96.99%;而在方铅矿表面的吸附率为20%左右;两种矿物表面的吸附在较短的时间内即可达到平衡;pH值是影响Nocardia在两种矿物表面发生选择性吸附的关键因素,当pH为3～10时,选择性吸附现象明显;而当矿浆浓度超过6 g/L和菌液浓度为0.5～4 g/L时,有利于选择性吸附;温度对吸附效果影响较小.扫描电镜检测结果表明,Nocardia细胞外膜表面的菌丝是重要的吸附位;矿物解理面状态、Nocardia表面基团的桥连作用和静电力是导致选择性吸附的关键.

早前寒武纪硫铁矿矿床Fe同位素特征及其地质意义——以山东石河庄和河北大川为例

报道了山东石河庄和河北大川地区前寒武纪层状硫化物矿床中黄铁矿单矿物的Fe同位素组成。相对于标准物质IRMM-014,大川黄铁矿的ε57Fe为-38.8^-13.1,石河庄黄铁矿的5ε7Fe为-39.4^-15.1,表明形成这两个层状硫化物矿床的新元古代海水富集Fe的轻同位素。世界不同地区新太古代黑色页岩中的黄铁矿的Fe同位素组成与华北两个硫铁矿矿床的Fe同位素特征基本一致,暗示新太古代海洋富集Fe的轻同位素可能是全球现象。导致早前寒武纪海洋富集Fe轻同位素的原因是海水中大量的Fe被氧化形成了富集Fe重同位素的磁铁矿和赤铁矿。