Electrochemical behaviors of gold and its associated elements in various complex agent solutions

Thermodynamic properties and electrochemical behaviors of gold and its associated elements, such as silver, copper, nickel and iron, in various complex agent solutions were studied. Within CS（NH2）2, S2O2-3 and SCN- systems, alkaline thiourea is the optimal nontoxic lixiviating agent substituting cyanide from the viewpoint of thermodynamics. The electrochemical study indicates that the anodic dissolution current densities of gold are 2.616, （1.805,） 1.267, 1.088, 0.556, and 0.145 mA·cm-2 respectively in the solutions of cyanide, alkaline thiourea containing Na2SiO3, SCN-, acidic thiourea, alkaline thiourea and thiosulfate at the potential of 0.500 V. Comparing various lixiviating agents, the alkaline thiourea solution containing Na2SiO3 is of prominent selectivity in leaching gold, in the potential range from 0.500 to 0.600 V, which is most efficient for leaching gold selectively instead of cyanide. The effect on leaching gold is similar to that in the cyanide system.

Improved recovery of a low-grade refractory gold ore using flotation–preoxidation–cyanidation methods

In this work, different flotation–preoxidation–cyanidation methods are considered for treating a lowgrade refractory gold ore. On the one hand, the results of selective flotation show that 22% and 31.1%of total Sb and As, respectively, remained in the final tailings and only about 28% of the total Au remained for further cyanidation processes. On the other hand, in bulk method of flotation the maximum Au recovery of 90.6% achieved after 60 min of flotation at the grind size with K80 of 146 micron. In addition, the bulk flotation method resulted in the concentrate with low concentrations of Sb and As elements. To improve the recovery of low-grade refractory gold ores, flotation should be followed by roasting, biological, or pressure oxidation processes so that the gold could be liberated prior to cyanidation processes. It is also found that the pressure oxidation pre-treatment of the concentrates prior to cyanidation may yield high gold recoveries of over than 83%. In these processes, recoveries are controlled by the temperature and the oxygen partial pressure in the solvent. However, by utilizing the bio-oxidation technique, the oxidation of sulfur to sulfate cannot be completed and, consequently, the gold recovery may be limited to only 72.2%.

Characterization of Gold Bearing Placers and Associated Minerals in the Elogo Region (North-West Congo Republic)

The Elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The goal of this study is to contribute to the exploration of the primary gold deposit in the Elogo Region (North-West of Congo Republic). The methodology consisted of characterization of placers deposits by their lithology, mineralogy and the gold grains shape, in order to constrain the source of gold with the respect to the local geology. The results obtained show that alluviums are polygenic and yields seventeen mineral species composed of zircon, olivine, magnetite, ilmenite, gold, garnet, rutile, coltan, cassiterite, monazite, apatite, amphibole, tourmaline, pyrite, limonite, chromite, and amphibole. The morphoscopy of gold grain shows single grains and grains with quartz inclusions that suggest their relationship with quartz veins. The gold grains are flattened, sub-flattened, and rounded. The northern region of Elogo characterized by a dominance of coarser quartz-included gold grains indicates a proximal proparte origin (less than 50 m), while the southern region, showing less coarse and more evolved grains with choc marks, appears to be associated with a distal pro-parte origin (more than 300 m). The multivariate statistical analysis shows seven classes of samples corresponding to the mineralogical paragenesis suggesting various sources, consisting of high-grade metamorphic, granitoids, pegmatites, basic and ultrabasic rocks, and BIFs that provided minerals to the placers. Gold mainly comes from hydrothermal quartz veins and probably from the peptization of gold from the weathering of sulfides occurring in the BIF. In the Elogo region, gold exploration for primary deposits should look for and follow the hydrothermal system developed in this region. Chemical analysis for the gold grains and associated minerals is necessary to better guide the proposed geochemical prospecting.

The Effects of Applying the Association of Al,K,and Sn in Stream Sediments for Gold Exploration in Different Landscapes

Geochemical data of altered wall rocks are important for the metallogenic prognosis of hydrothermal gold deposits. Indicator elements of altered wall rocks such as K, AI, As, Sb, and Hg have been successfully used to assess gold anomalies in lithogeochemicai survey. However, such researches have rarely been done in stream sediment survey for the exploration of gold from various landscapes. On the basis of the geochemical analysis of altered wall rocks of gold deposits in the cold desert areas of Gansu （甘肃） Province in Northwest China, it is found that the combination of AI, K, and Sn could serve as an important indicator of hydrothermal gold deposits and can be used to evaluate the metallogenic prospective of gold anomalies in stream sediments. More studies performed in the cold grassland areas and the moderate-low relief mountainous areas showed that, both weak and strong geochemical anomalies can be extracted, if strictly abiding by the ways of calculation and addition of the binary values of the indicator elements with equal weight, and this provides the sound delineation of metallogenic perspective areas.

Reorganizing the Local Boy Scouts Associations in the Northern Province of the Gold Coast Colony

Imperialist Robert Baden-Powell’s Boy Scouts Association started in the Gold Coast Colony during the First World War and schooled boys for nationality during the 1920s.This paper uses archival documents to discuss how Chief Scout Governor Gordon Guggisberg,who was brigadier general during the First World War,reorganized the Boy Scouts Association in the Northern Province of the Northern Territories Protectorate.The scout officers at the Local Boy Scouts Associations had the power to fashion desire but were not supposed to have consequences on political power.As government officers and scout officers they had warrants to work at the government schools at Gambaga,Wa,and Lawra to attain money locally for kits to instruct and invent the identity,customs and nationalist categories of schoolboys performing the British Empire.

New Occurrence of Gold Mineralization at the Eastern Part of Wadi El Gemal, South Eastern Desert, Egypt

The basement rock units of the study area are represented by metasediments-metavolcanics association, diorite rocks, granodiorites and syenogranites. The whole sequence is cut by basic dykes, pegmatites and different quartz (jasper) veins. Metasediments-metavolcanics association is represented by hornblende schist and metadacite respectively. There is visible sulfides mineralization in hornblende schist, metadacite and diorite rocks at their contacts at the wadi level. So, polished sections were prepared to study opaque minerals under the ore microscope, which reveals the presence of gold, pyrite and goethite. The radioactivity of this area is weak, where the average eU contents in metasediments-metavolcanics association, diorites, granodiorites, syenogranites, pegmatites and jasper veins are 2.8 ppm, 1.9 ppm, 3.26 ppm, 4.91 ppm, 4.32 ppm and 6.7 ppm respectively. The intrusion of granodiorite rocks may act as a source for hydrothermal solutions ascending along fractures of all older rocks. During this stage, a chemical reaction of hydrothermal fluids with metasediments-metavolcanics association and diorite rocks lead to forming sericite and enrichment of silica content. The enrichment of silica content led to the formation of quartz-diorite. Also, iron derived from the host rocks and sulfur from the hydrothermal fluids could have formed pyrite while the gold was precipitated at the contact between metasediments-metavolcanics association and diorite rocks.

Reconstruction of the Indigenous Sources of Gold of the Glu-Kharinsky Placer (Kolyma River Basin, Magadan Region, Russia)

A comparative analysis of typomorphic features of gold placers and indigenous sources of gold was carried out for the Glukharinsky ore-placer node (the Nadezhda deposit and Glukharinskoye, Tyomnoye, and Tyi-Jurye ore occurrences). A correlation between fineness of placer native gold and composition of relic minerals preserved inside gold particles was obtained for the first time. This made it possible to establish mineral parageneses of native gold from potential indigenous sources. The study of placer gold fineness in combination with com-position of mineral inclusions allowed us to identify seven types of gold paragenesis: petzite-hessite with a fineness of 855‰, pyrite-polybasite-galena (a fineness of 670‰), bismuth telluride (900‰), cosalite-vikingite (790‰), galena (870‰), glaucodot (950‰), and hydrohematite (840‰). It was also shown that the placer contains the material from ore occurrences of different formation: gold-quartz-porphyry occurrences in granitoids (Au-Te-Bi type) and gold-silver occurrences. The method developed by us allows one to estimate the percentage of each ore source in placer formation.

An Interesting Element Association of Au-Sb-As-W and Its Geochemical Interpretation─A Review

The occurrences and characteristics of the association of An-Sb-As-W are summa-rized. An interpretation of the association is given according to the fact that the content of re-duced sulfur in the ore-forming solution is much high relative to Cl in this kind of ore deposits,especially for the Au-Sb-As with W, using the data on their complexes and solubility. The highfineness of gold and the separation of gold from the base metals Cu, Pb, Zn, and sometimesfrom Ag in this kind of ore deposits are also interpreted.

The Tamale Local Boy Scouts Association in the Northern Territories Protectorate in the 1920s

In 1907,military leader Robert Baden-Powell started the Boy Scouts Association in England as the British colonial government officers instituted Tamale village as the administrative centre of the Northern Territories Protectorate.Sam Yarney worked with Frank Collyer the European bank cashier and scoutmaster who started the Boy Scouts in the Gold Coast Colony in 1914,the year the First World War started.In 1922,Governor Gordon Guggisberg,who was brigadier general during the war was the chief scout.He reorganized the Local Boy Scouts Association in the Tamale Government School that received select boys from various schools in the Northern Territories Protectorate.The schoolboys excelled in the Standard VII and Civil Service Examinations to work with the government institutions and train as teachers and telegraphists.Arthur James Philbrick the chief scout commissioner of the Northern Territories employed Yarney as the assistant scout commissioner in the Southern Province to take on the staff of the reorganized Tamale Local Boy Scouts Association and register the 1st Tamale Troop.The scout officers subscribed to a Scout Fund to buy kit,for the schoolboys who passed the Tenderfoot Tests to buy uniforms and perform at events.

赣东北银山矿田铜矿石工艺矿物学研究

为了掌握银山矿田铜矿石中伴生金的赋存状态及主要矿石矿物的工艺特征,利用光学显微镜、电子显微镜、电子探针、XRD、MLA、选择性溶解试验等多种综合手段,对银山矿田铜矿石进行了系统的矿物工艺学研究。结果表明:银山铜矿石中矿物主要为黄铁矿和黄铜矿,其次为黝铜矿、砷黝铜矿、斑铜矿、辉铜矿、铜蓝等;金矿物以自然金为主,同时还有少量的银金矿,嵌存状态以包裹金为主,占46.41%,粒间金占44.17%,裂隙金占9.42%;金矿物粒度以微粒金为主,占94.61%,还有少量细粒金和中粒金,未发现粗粒金及巨粒金。研究结果为制定适宜的选别工艺流程和药剂体系提供了理论基础。

基于大数据关联规则算法的卡林型金矿床元素富集规律及找矿方法研究

大数据时代的到来,为卡林型金矿床开拓了新的找矿思路。本研究应用关联规则算法,挖掘滇黔桂“金三角”卡林型金矿床内微量元素与金矿化海量数据之间的关联性,提取元素异常组合,分析控制因素,定量构建找矿标志。结果显示矿床内元素异常组合分为4组:(1)强正关联显著富集元素(As、Sb、Hg、Tl、Ag、W和Rb),显示硫化和黏土化作用;(2)较强正关联略富集元素I(Zr、Th、Ta、Nb和Hf)和强负关联强迁出元素(Li和Sr),显示去碳酸盐化作用;(3)较强正关联略富集元素II(Sn、Zn、Ni、V、Co和Cu),显示硫化作用;(4)弱关联基本无富集元素(Cd、Pb、Ba、Bi、U和Mo),与成矿无显著关联。从大数据角度获取的元素异常组合,与学界关于Au主要在去碳酸盐化、硫化和黏土化条件下形成的认识一致。通过关联规则算法分别对与硫化和去碳酸盐化相关的元素建立定量找矿标志。硫化找矿标志:样品中As、Hg、Sb、Tl、W、Ag和Rb等元素内中高含量项数≥1、≥2、≥3、≥4和≥5时,对应的Au矿化分别为≥4.5×10^(-9)、≥47.0×10^(-9)、≥150×10^(-9)、≥500×10^(-9)和≥1000×10^(-9);样品内高含量项数≥1、≥2和≥3时,对应的Au矿化分别为≥150×10^(-9)、≥500×10^(-9)和≥1000×10^(-9);找矿过程中两组指标配合使用,确保不漏矿,高效圈矿。去碳酸盐化找矿标志:样品中Zr、Th、Ta、Nb和Hf含量任意两项出现正异常,认为样品经历过去碳酸盐化作用。定量识别的硫化和去碳酸盐化找矿标志可望在卡林型金矿找矿预测中发挥重要作用。本研究基于关联规则算法分析矿床元素富集规律、控制因素和定量构建找矿标志的方法,也可为其他类型矿床开展类似研究提供新思路。

国外某大型选矿厂矿石工艺矿物学特征及选矿工艺

铜是新能源时代不可或缺的重要金属,为高效开发国外某低品位铜矿石资源,鉴于工艺矿物学对矿石选矿工艺的重要作用,利用MLA、光学显微镜等测试分析技术,对该矿石开展了工艺矿物学研究,获得了重要的工艺矿物学资料,指导了选矿厂选矿工艺的确定。结果表明,矿石中主要金属硫化物为黄铜矿和黄铁矿,脉石矿物以石英、钾长石为主,其次为白云母、钠长石、黑云母等。含铜矿物基本为黄铜矿,少量的(蓝)辉铜矿和其他含铜矿物,在-74μm含量占62%的情况下,黄铜矿解离情况良好,粒度分布均匀,大部分集中在利于浮选回收的粒级范围内。该矿石在三次粗选、粗精矿分级再磨、三次精选、一次精扫选的选别处理下,当原矿含铜0.41%、含金0.24g/t,可获得铜精矿含铜20.83%、含金9.25g/t,铜回收率90.43%、金回收率68.60%的选矿指标。实现了低品位含金硫化铜矿石资源的高效开发利用。

国外某低铜锌高硫复杂金银矿选冶综合回收试验研究

针对国外某金银矿中黄铁矿含量高、铜锌品位低(Cu 0.11%、Zn 0.22%)、部分金以硫化矿粒间金及裂隙金赋存,银矿物种类多而杂的特点,采用“尼尔森重选-铜优先浮选-全硫混浮抛尾-全硫精矿细磨浸出-氰化尾渣选锌”的选冶联合新工艺,实现了该矿中金、银矿物的绿色分类快速提取和伴生低品位铜、锌矿物的高效综合回收。选冶全流程试验获得总回收率:Au 91.0%、Ag 77.3%、Cu 77.5%、Zn 63.2%,其中重选金银精矿含Au 41523.71 g/t、Ag 13763.36 g/t,铜精矿中含Au 400.8 g/t、Ag 5429.00 g/t、Cu 21.19%,锌精矿中含Zn 35.14%,全硫混浮尾矿(抛废)产率为74.6%。

有色金属矿中伴生金银选矿进展

有色金属矿中伴生的金主要以独立矿物形式存在,银主要以独立矿物、类质同象形式存在,金、银矿物种类繁多,载体矿物分散,且金、银独立矿物嵌布特征及选矿回收工艺条件与主金属矿物存在差异。提高磨矿细度有助于金、银矿物的单体解离,尤其是使硫化铁矿物、硫化砷矿物及脉石矿物中的金、银独立矿物充分单体解离,是提高有色金属矿中伴生金、银选矿回收率的关键。针对不同的矿石性质,以主金属矿物为主且兼顾伴生金、银独立矿物,采用合适的浮选工艺、浮选-重选联合工艺、选矿-冶炼联合工艺有助于提高有色金属矿中伴生金、银的回收利用率。浮选是有色金属矿选别分离的主要工艺,针对铜、铅主金属矿物采用优先浮选、部分混合优先浮选、异步浮选工艺流程,使用组合捕收剂、新型高效捕收剂配合低碱、无氰调整剂,合理选择使用闪速浮选机、浮选柱等与常规浮选机联合使用,有益于强化伴生金、银的选矿回收。

低碱工艺组合药剂回收某铜矿中铜的试验研究

某铜矿主要金属矿物是黄铜矿和黄铁矿,选矿工艺流程为原矿粗磨—铜硫混选后抛尾—混选精矿再磨后铜硫分离,由于铜硫混选采用的捕收剂丁基黄药捕收力较强、选择性较差,混选精矿采用高碱石灰工艺进行铜硫分离,存在石灰易结垢、固结、堵塞管道、用量不易控制、矿浆pH高以及不利于伴生金、银等贵金属的综合回收等缺点。针对原工艺流程存在的问题,根据矿石性质,在现场工艺流程基础上,采用选择性的铜捕收剂EP与少量丁基黄药组合作捕收剂,进行了低碱条件下浮选回收铜的试验研究。结果表明,采用EP+丁基黄药组合捕收剂的低碱工艺可有效回收某铜矿石中的铜矿物,闭路试验获得了含铜24.11%、含金5.30 g/t、含银62.05 g/t,铜回收率90.71%、金回收率62.94%、银回收率60.15%的铜精矿。与现场丁基黄药高碱工艺相比,新药剂低碱工艺铜精矿的铜品位和铜回收率相当,铜精矿中伴生金、银的品位分别提高了0.3 g/t、1.88 g/t,金、银回收率分别提高了4.68、2.81个百分点。

热液金矿中部分伴生元素迁移沉淀形式及成矿流体地球化学过程的微观判断

黄金(Au)因其稀有及稳定的化学性质,已成为重要的战略金属和贵金属,在许多方面和领域得到了广泛的应用。金矿床常伴生一些贱金属,如铅、锌、银、铜等,对它们综合利用可获得较高经济价值。本文讨论了热液矿床中金、铅、锌、银、铜的迁移及沉淀机制,借此为各个金矿床进一步工作提供参考。笔者还介绍了判别金矿成矿流体地球化学过程的部分特征,将有利于判断流体中发生的地球化学变化,进而了解成矿过程及矿化有利部位,为进一步找矿提供依据。

有色金属硫化矿中伴生金银资源回收研究进展

有色金属矿产资源中伴生的金银矿物是贵金属金银资源的重要来源,伴生金银的回收一直是各国选矿工作者研究的重点。伴生金银资源主要分布在硫化铜、硫化铜铁及硫化铅锌矿石中,由于共伴生金银嵌布粒度粗细不均,金银捕收剂对矿石的适应能力不强,导致现有浮选工艺及药剂制度难以满足伴生金银回收的要求,严重影响了伴生金银的回收效果。在伴生金银工艺矿物学研究基础上,针对不同矿石中伴生金银资源的回收特点,选矿工作者通过改进和强化磨矿工艺、选择合理的工艺流程及开发多种新型金银捕收剂,显著提高了有色金属硫化矿中伴生金银资源的选矿指标。

难处理金矿中伴生矿物对氰化浸出的影响

对金矿石中常见的几种伴生矿物在氰化浸出中的影响进行了分析,同时采用化学试剂配制标准液的方式,考察了Fe2+,Cu2+,As3+对氰化物消耗的影响.试验结果表明:铁矿物中,磁黄铁矿对氰化浸出的影响较大,使溶金速率下降28.1%,氰化物耗量增加4倍,而黄铁矿与赤铁矿对氰化浸出的影响较小;铜矿物中,黄铜矿与辉铜矿对氰化浸出都具有很大影响,其中辉铜矿可使溶金速率下降36.81%,氰化物耗量增加10倍;砷矿物中,雄黄与雌黄对氰化浸出极其有害,使溶金速率分别下降41.95%和49.90%,氰化物耗量分别增加13.8倍和15.0倍,相反毒砂在氰化体系中比较稳定,对氰化浸出的影响较小.离子耗氰试验中,Fe2+,Cu2+都会大量消耗体系中的氰化物,As3+则不与氰化物反应,不会造成氰化物消耗,因此硫氰根的形成才是导致砷矿物大量消耗氰化物的主要原因.

胶东牟平-乳山金矿带金青顶金矿碲化物矿物的特征及沉淀机制

通过光学显微镜、电子显微镜并结合能谱分析,在金青顶金矿Ⅱ号矿脉深部除含碲化物碲银矿、碲金银矿和碲铋矿外,首次发现碲金矿的存在,进一步证实了前人对于该矿床中存在碲金矿这一新矿物的推测,也打破了该金矿深部无碲金银矿的传统认识。这些碲化物呈连生体或者细脉状产于黄铁矿等硫化物、石英与黄铁矿裂隙中。在金银碲化物矿物中,Te含量变化较小,Au含量变化较大,与Ag呈负相关,与Bi为正相关。结合金-银-碲矿物成分-共生图解,对金银碲化物矿物的共生组合特征进行了研究。研究表明,Te总是优先与Ag结合形成碲银矿或碲金银矿,只有热液中Ag被消耗后才与Au结合形成碲金矿,最后Te被耗尽,矿液中残留很多的Au,从而形成自然金,说明随着成矿过程的演化,成矿热液可能逐渐富金,具体表现为碲银矿-碲金银矿-碲金矿-自然金的析出顺序。

甘肃寨上金矿床中白钨矿矿体的发现及其特征

位于西秦岭礼(县)—岷(县)成矿带西段的寨上金矿床,是近年发现的一个大型微细浸染型金矿。在研究甘肃寨上金矿床物质组分的过程中,笔者通过对岩矿石的等离子质谱分析和对矿物的反光显微镜下观察、电子探针分析,发现寨上金矿床存在白钨矿的富集体。根据化学成分圈定出了独立的白钨矿矿体,确认该矿床为金-钨-锑(自然金-白钨矿-辉锑矿)建造矿床。其与四川西北部马脑壳金-钨-锑矿床在地质背景、含矿岩石、矿化形式、矿物组合、元素组合和成矿过程相似。鉴于在川甘陕三角地带泥盆系—三叠系中类似寨上的金矿床、矿点众多,注意在此类金矿中分析和评价钨等有用组分,对提高金矿的综合利用价值是十分重要的。