Fe extraction from high-silicon and aluminum cyanide tailings by pretreatment of water leaching before magnetic separation

Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.

Treatment of copper-rich gold ore by cyanide leaching, ammonia pretreatment and ammoniacal cyanide leaching

The treatment of a copper sulphide-bearing gold ore by direct cyanide leaching, ammonia pretreatment and ammoniacal cyanide leaching was investigated. Dissolution behaviour of gold and copper in these leaching systems was demonstrated. Severe interference by the copper containing sulphides with cyanide leaching of gold is observed at p（NaCN）〈5 g/L. This is consistent with speciation calculations. Ammonia pretreatment is shown to readily eliminate the copper interference, allowing almost complete extraction of gold with concomitantly low reagent consumption in subsequent cyanide leaching. In ammoniacal cyanide system, Box-Behnken experimental design shows the main and interaction effects of NH3, NaCN and Pb（NO3）2. The concentrations of NH3 and NaCN are statistically confirmed to be significant factors affecting extraction of gold while the effect of Pb（NO3）2 is limited. Increasing the concentration of NH3 improves the selectivity and extent of gold extraction and reduces the cyanide consumption. The contribution of reagent interactions to gold extraction is statistically insignificant. These findings highlight that ammonia pretreatment and ammonia-cyanide leaching are promising approaches for the treatment of gold ores with high copper sulphide content.

Co-intensification of cyanide leaching gold by mercury ions and oxidant

The effects of mercury ions on gold cyanidation were studied. The results show that under low cyanide concentration, gold cyanide process is controlled by CN- transfer, while at higher cyanide concentration, there forms passivation on gold surface. Therefore, chemical oxidation of gold in cyanide solution of higher concentration is controlled by surface reaction. Small quantity of additions of mercury ions bring about great increases in anodic gold dissolution rate, decreases the passivation and reduces the equilibrium activated energy. In addition, they also markedly change the effect pattern of cyanide concentration. Mercury ions show positive effects on cathodic reduction of oxygen and raise the rate of electrochemical step of the cathodic reduction of oxygen. Addition of a certain amount of hydrogen peroxide is confirmed to be an effective way for intensification of cathodic process on gold electrode. Active potential range and current peak on anodic dissolution are enlarged when being co-intensified with Hg^2＋ and hydrogen peroxide. Co-intensifying effect may be obtained and gold from gold concentrates. gold leaching rate is considerably increased on cyanide leaching of

Influence of copper minerals on cyanide leaching of gold

The paper thermodynamically examined the behavior of various copper minerals in cyanide solu tions and investigated the influence of copper minerals on cyanide leaching of gold. In elucidating the influence of copper minerals on cyanide leaching of gold, copper minerals were classified into two types according to their solubility in cyanide solutions by proposing two concepts, cyaniding easily soluble copper (E Cu ) and cyaniding insoluble copper. The former involves copper occurrence in metal, oxides and secondary sulfides, and the latter refers mainly to primary sulfides. Experimental results show that not all the total copper in an ore affected cyanide leaching of gold, while cyaniding easily soluble copper turns out to be the decisive factor that interferes with gold cyanidation by causing decrease in gold cyanidation recovery and increase in cyanide consumption. When cyaniding easily soluble copper content ( w E(Cu) ) lies in the range of 0 0.25%, it linearly affects gold cyanidation recovery ( R ) as well as cyanide consumption ( m c). The regression equations have been worked out to be R (%)=94.177 5-142.735 7 w E(Cu) with a correlation coefficient of -0.902 and m c=5.590 7+33.572 9 w E(Cu) with a correlation coefficient of 0.945, respectively.

Leaching kinetics in cyanide media of Ag contained in the industrial mining-metallurgical wastes in the state of Hidalgo, Mexico

The leaching kinetics in cyanide media of the silver contained in the Dos Carlos waste tailings at the City of Pachuca de Soto, Hidalgo State, Mexico were carried out. The used material contained the following chemical composition: 56 10-6of Ag, 0.6 10 6of Au and 70.43%(by weight) of SiO2; 7.032%(by weight) of Al2O3; 2.69%(by weight) of Fe; 0.46%(by weight) of Mn; 3.98%(by weight) of K2O; 3.34%(by weight) of CaO; 2.50%(by weight) of Na2O; 0.04%(by weight) of Zn; 0.026%(by weight) of Pb. The mineralogical phases present were the following: Silica, albite, argentite, berlinite, orthoclase, potassium jarosite, and natrojarosite. In the leaching kinetics in cyanide media, and under the studied conditions,the effect of the CN concentration on the reaction rate has no effect on the whole process of alkaline cyanidation, of which the reaction order is n 0. Temperature has an effect on the cyanidation rate of the reaction, with an activation energy of 47.9 KJ/mol. At the same time, when the particle size decreases there is an increase in the reaction rate, which is inversely proportional to the particle diameter; when increasing the NaOH concentration there is an increase in the reaction rate Kexp, with a reaction order(n) of 0.215 under the studied ranges.

Co-intensification of gold leaching with heavy metals and hydrogen peroxide

Co-intensification was researched to accelerate gold leaching with regards to its electrochemical nature by using anodic intensifiers of heavy metal ions (Pb2+,Bi3+,Tl+,Hg2+ and Ag+) on the basis of hydrogen peroxide assistant leaching on three different types of materials which were classified as a refractory sulphide gold concentrate,an easily leachable sulphide gold concentrate,and a low grade oxide gold ore according to their leaching characteristics.The results showed that,favorable co-intensification effects on the three materials were obtained and leaching time of gold was effectively shortened to no longer than 12 h from 16 to 24 h for hydrogen peroxide assistant leaching.For the five tested heavy metal ions,Bi3+and Tl+ presented co-intensifying effect on all the three materials,and Hg2+ caused co-intensifying effect on both refractory and easily leachable sulphide gold concentrates,and Pb2+ and Ag+ only had co-intensifying effect on the easily leachable sulphide gold concentrate.

Cyanidation of gold clay ore containing arsenic and manganese

The extraction process of gold and silver from the gold clay ore containing arsenic and manganese was investigated.With the conventional technique,the leaching rates of gold and silver are 78.23%and 49.02%,respectively.To eliminate the negative effects of arsenic and manganese on cyanidation and increase the gold and silver leaching rates,a novel catalyst was added.The content of the catalyst used in the process was 8 g per 500 g org sample,the sample size was 60μm and the pH value was kept between 10 and 11.Leaching with the catalyst for 3-5 h under certain conditions,the gold leaching rate increased to over 90%and the silver leaching rate increased to 80%-90%.The catalyst can effectively liberate gold and silver from the enclosure of arsenic and manganese and the industrial experiment has great significance to the development and utilization of the gold clay ore containing arsenic and manganese.

LEACH OUT GOLD AND SILVER FROM SULFIDE CONCENTRATE CONTAINING COPPER WITH CYANIDE AND AMMONIA SOLUTIONS

A cyanidation leaching process for a sulfide concentrate containing gold and silver with ammonia and other complexes was investigated,and its potential in decrease of cyanide consumption was examined.The equilibria behaviors of copper and other metal ions in the CN-NH,-H_(2)0 system and the CN—NH,—EDTA-HjO system were analyzed by a microcomputer program.Experiments revealed that the leaching yield of gold in ammonia-cyanide solutions was raised from 86%to 99%from addition of EDTA in a certain concentration and its cooperative action with ammonia on the cyanidation of gold.Meanwhile,the leaching yield of silver was significantly increased from about 20%to 55%and the consumption of cyanide was decreased.

A Review on Alternative Gold Recovery Re-agents to Cyanide

The importance of gold recovery from low grade ores and flotation tailings is continuously increasing due to raising gold demand and thereby high gold prices. However, due to raising social awareness of the ecological impacts of cyanidic gold extraction and environ-mental specifications, the development and the implementation of alternative hydrometallurgical extraction processes have been a focus for many research institutions in last decades. Present work gives a comparison between compatible extraction reagents, with focus on less harmful processes. The target of this review is to point out the best cyanide-free processes of following methods and reagents: Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cyanide.

Ammonium Thiosulfate Ecological Viable Alternative to Replace Sodium Cyanide in Gold and Silver Dissolution Ores

The southern region of the state of Chihuahua is mining by origin, as this has been proved ghost towns of Minas Nuevas, it is also called Villa Escobedo, Emerald and Blue. Minerals are nonrenewable resources. There are only reserves and waste deposited in tailings ponds of low-rade precious metals （gold and silver）. A conventional method for recovering gold and silver ore is low-grade cyanidation and the solvent consider toxic and highly dangerous for the flora, fauna, humans and the environment. The mechanism of cyanide poisoning is inhibition of cytochrome oxidase--an enzyme needed for cell respiration. Without compromising efficiency, sensitivity and cost of the process, the toxic solvent is replaced by a less aggressive one, which helps the environment, public and occupational health. （NH4）2S203 has no appreciable damage to conservative amounts, is a selective aqueous solvent for leaching gold and silver, easy to get and manipulate. This work is done in the Technological Institute of Parral in a low-grade ore from the southern region of the state of Chihuahua. This document has been enriched presented in the IMEC 2014, with the increase of series Ⅴ and Ⅵ.

助浸剂对草酸浸出氰化尾渣中赤铁矿效果的影响

为揭示浸出液中Fe^(3+)的形态分布对焙烧氰化尾渣中赤铁矿浸出效果的影响,研究了H_(2)C_(2)O_(4)、H_(2)C_(2)O_(4)-H_(2)SO_(4)和H_(2)C_(2)O_(4)-K_(2)C_(2)O_(4)对赤铁矿浸出效果的影响,并采用响应面法对H_(2)C_(2)O_(4)-K_(2)C_(2)O_(4)浸出赤铁矿工艺进行了优化。结果表明:Fe^(3+)的形态分布直接影响赤铁矿的浸出效果。H_(2)C_(2)O_(4)与K_(2)C_(2)O_(4)作为除铁剂,n(H_(2)C_(2)O_(4))/n(K_(2)C_(2)O_(4))摩尔比、(C_(2)O_(4)^(2-))_(T)过量倍数及浸出温度影响浸出pH,而pH和c(C_(2)O_(4)^(2-))_(T)应满足浸出的Fe^(3+)转化成Fe(C_(2)O_(4))_(3)^(3-),Fe^(3+)只有以Fe(C_(2)O_(4))_(3)^(3-)形态存在,才能缩短赤铁矿浸出时间、提高赤铁矿浸出效果。H_(2)C_(2)O_(4)-K_(2)C_(2)O_(4)除铁优化条件为:n(H_(2)C_(2)O_(4))/n(K_(2)C_(2)O_(4))=1.03、(C_(2)O_(4)^(2-))_(T)为理论量的1.37倍、浸出温度94℃、液固比L/S=5mL/g、时间30min。在优化条件下,实际值和预测值分别为98.42%和97.73%,相对误差为0.69个百分点。各因素对除铁效果影响大小排序为(C_(2)O_(4)^(2-))_(T)过量倍数、浸出温度、n(H_(2)C_(2)O_(4))/n(K_(2)C_(2)O_(4)),其中n(H_(2)C_(2)O_(4))/n(K_(2)C_(2)O_(4))与浸出温度有一定的交互作用。H_(2)C_(2)O_(4)-K_(2)C_(2)O_(4)浸出焙烧氰化尾渣中赤铁矿结果进一步证明,草酸-草酸盐混合浸出体系是一种高效除铁剂,且浸出液中的铁资源化利用工艺简单,其优势是现有除铁剂无法比拟的。

某高硫含砷难处理金矿选冶试验研究

针对某金矿中硫、砷含量过高且易泥化导致金回收率低的问题,采用阶段磨矿阶段浮选—浮选尾矿非氰浸出工艺流程开展试验研究。研究结果表明:在一段磨矿细度-0.074 mm占75.6%、二段磨矿细度-0.043 mm占78.1%,酸化水玻璃用量为1 650 g/t,硫酸铜用量为350 g/t,丁基黄药+丁铵黑药用量为(240+96) g/t,松醇油用量为160 g/t的条件下进行浮选试验,浮选尾矿采用非氰浸出剂进行非氰浸出,最终获得了浮选金精矿金回收率84.40%,浮选尾矿金浸出率10.52%,总金回收率94.92%的回收指标。研究结果对开发该类金矿资源具有重要指导意义。

低毒提金剂的研究现状与应用

随着我国将氰化尾渣及含氰废水处理污泥纳入新版《国家危险废物名录》,黄金企业面临着巨大的环保压力,故发展无毒或低毒提金工艺成为黄金行业的迫切需求。然而,由于提金成本高、浸出液中金回收工艺复杂、提金溶液循环困难等,硫代硫酸盐、硫脲、硫氰酸盐等无毒药剂至今尚未得到大规模推广应用。相较之下,低毒提金剂在毒性、提金效果、提金成本等方面相比氰化钠有着独特优势,具有良好的应用前景。本文首先对典型低毒提金剂的基本性质特征进行了概述,然后系统归纳了其合成工艺、合成机理及浸出机理,总结了低毒提金剂在国内外的相关应用,最后提出了低毒提金剂目前存在的问题,并对未来研究重点进行了展望。

吉林省某金矿石氰化浸出试验研究

吉林省某金矿具有嵌布粒度较细、包裹金含量较高的特点,矿石工艺类型为少硫化物石英脉型含金矿石,氰化浸出试验分别研究了磨矿细度、氧化钙用量、碱处理时间、氰化钠用量、浸出时间、矿浆浓度对该矿石浸出指标的影响。试验结果表明:当磨矿细度为-0.045 mm质量分数90%,氧化钙用量2.5 kg/t,碱处理时间1 h,氰化钠用量1 kg/t,浸出时间24 h,浸出浓度40%,氰化浸渣品位0.50 g/t,金浸出率可达到92.10%。

氧化剂对氰化体系下黄铁矿溶解行为的影响及机理

本文针对氰化过程金精矿中黄铁矿与氰化物作用特性,对比研究次氯酸钠、过氧化氢和过硫酸钠对黄铁矿的预氧化处理效果,并对黄铁矿溶解特性、氰化物消耗、硫氰酸根离子浓度及氧化渣表面物质组成变化进行了分析。结果表明:3种氧化剂均能抑制黄铁矿的氰化溶解,当以过硫酸钠为氧化剂时,氰化物的消耗量减少51.72%,硫氰酸根离子的生成量减少75.97%,同时氰化体系中的氧环境得到改善。但以次氯酸钠为氧化剂时,氯化物的释放导致氰化物的消耗量增加10.34%。SEM-EDS及XPS分析结果表明,氧化剂的使用导致黄铁矿表面形成了不与氰化物作用的FeO、FeSO_(4)和Fe_(2)(SO_(4))_(3),从而抑制了黄铁矿氰化溶解,优化了氰化提金系统的浸出环境。

某高硫砷难处理金矿石选矿试验研究

某高硫砷金矿石金、银品位分别为2.90 g/t和59.00 g/t,As含量为6.06%、S含量为5.20%。矿石中金矿物粒度较细,均为显微金与细粒金,其与黄铜矿、磁黄铁矿等硫化矿连生于毒砂中,单体解离困难。为进一步实现高硫砷难处理金矿的高效利用,在矿石工艺矿物学研究的基础上,进行了浮选和氰化浸出试验研究,确定采用浮选—氰化浸出的联合工艺流程进行试验。结果表明:适宜药剂制度下,原矿在磨矿细度为-0.074 mm占75%时,进行1次粗选试验,粗精矿再磨至-0.038 mm占99%时,进行2粗2精浮选—1次硫砷分离流程试验。最终获得金品位为17.19g/t、金回收率为79.06%,银品位为269.00 g/t、银回收率为68.73%的金精矿。将浮选尾矿磨至-0.010 mm占86%时,采用氰化浸出工艺处理,金浸出率为22.22%,银浸出率为57.78%。选冶综合金回收率达到83.71%,银回收率达到了86.80%,实现了金、银的有效回收利用。

滇西某红土型氧化矿洗矿分级-预选抛尾试验研究

滇西某红土型氧化金矿,共伴生Ag、Fe等有价金属,原矿含Au 1.72 g/t、Ag 17.50 g/t、TFe 28.19%、mFe 11.52%,该矿属原生矿经风化剥蚀-搬运沉积的表生作用成因矿体,岩体发生高岭土化,矿石多为砂土粉末状、蜂窝状。本文开展了系统的矿石性质、原矿细粒级浸出、原矿洗矿分级,以及细粒级磁选抛废等工艺试验研究,并对各作业参数对工艺指标的影响进行了分析。研究结果表明,该金矿中黏土矿物、细粒级含量高,原矿-0.038 mm粒级占比达42.89%,贵金属金以微细粒自然金为主,银以矿物包裹银、磁性铁矿物中银,以及弱磁性铁矿物中银三者为主,铁矿物主要是磁铁矿、(赤)褐铁矿,两种主要铁矿物与金、银的赋存关系较为紧密,该矿属低品位复杂难选多金属氧化金矿。对该矿石采用“原矿洗矿分级-泥砂分选,泥选系统预选抛尾”的工艺流程,可获得产率57.25%的分级粗砂,含Au 2.798 g/t、Ag 20.19 g/t、Fe 39.26%;产率22.35%的细粒混合粗精矿,含Au 0.329g/t、Ag 14.38g/t、Fe 16.19%,以及产率为20.40%的细粒抛尾尾矿,含Au 0.219 g/t、Ag 13.37 g/t、Fe 10.27%,损失率分别为Au 2.59%、Fe 7.44%、Ag 15.59%。该试验结果可为该资源后续的生产及类似矿石的资源开发提供一定的技术指导与借鉴。

印尼某金矿选矿试验研究

高砷难处理金矿是目前重要的黄金来源之一,也是传统浮选法和浸出法面临的巨大挑战。印尼某金矿石含金14.6g/t、含砷1.82%,该矿石为典型的高砷微细粒型难处理金矿石,自然金多分布于毒砂和闪锌矿间隙,少量包裹于脉石矿物中。该矿石的分选难点在于原矿中毒砂含量高、自然金裸露程度低、粒级以细粒和微粒为主,分选的重点在于降低砷含量、分离自然金和硫化矿。由于毒砂中存在着高含量的砷,会对选别造成不利影响,采用传统浮选工艺或全泥氰化工艺选别该矿石回收率较低,还会导致大量的砷富集于金精矿中,影响后续的冶炼过程。本试验重点研究了浮选—浮选尾矿氰化浸出工艺和氧化预处理—氰化浸出工艺,在浮选—浮选尾矿氰化浸出工艺中,为了增加细菌氧化的效率,先通过浮选对原矿进行富集得到金精矿,再进行细菌氧化处理,该方法在一定程度上降低了砷含量,使金精矿中的砷由5.98%降低至1.68%;在氧化预处理—氰化浸出工艺中,采用过硫酸钾(K2S2O8)作为氧化剂来处理原矿,结果表明,过硫酸钾对于氧化分解矿石中的黄铁矿和毒砂有较好的效果,砷含量由1.82%降低至1.05%。综合考虑,最终确定过硫酸钾氧化预处理—氰化浸出工艺的效果更好,金的浸出率可达88.49%,金的总回收率为87.97%,尾矿中金含量降至1.01g/t,实现了矿石中金的高效回收。研究结果可为此类难处理金矿的综合利用和回收提供参考和借鉴。

某高砷高硫复杂难处理金矿选冶工艺研究

为有效回收某高砷高硫复杂难处理金矿中的金,对该矿石开展了工艺矿物学分析,以及浮选、焙烧、氰化浸出等试验研究。结果表明,矿石中的金以硅酸盐包裹金为主,裸露金分布较少,黄铁矿、毒砂是主要的载金矿物,且整体粒度较细,多呈包裹体形式被脉石矿物紧密包裹。若采用常规的全泥氰化工艺,即使在磨矿细度为-0.038 mm占95%的条件下,金的浸出率也仅为18%左右,很难对矿石中的金进行有效回收。结合矿石的性质和金的嵌布特性分析,采用了优先浮选黄铁矿、毒砂等载金矿物的方法,从而来实现有效富集和回收矿石中的金,同时为改善浮选过程中细泥和脉石带来的影响,及强化对金的选别,采用了水玻璃+六偏磷酸钠的组合作为抑制剂,硫酸铜+硝酸铅的组合作为活化剂,丁基黄药+丁铵黑药的组合作为捕收剂。通过强化浮选过程中组合药剂的选择和使用,矿石采用浮选的工艺可获得金品位为21.05 g/t、金回收率为92.58%的金精矿。为了进一步有效解决所得金精矿品位低、有害元素砷含量高的问题,对金精矿进行了焙烧预处理。金精矿通过焙烧除杂后,使其包裹体结构被破坏,包裹金被裸露,然后对所得焙砂再采用氰化浸出的工艺来回收其中的金,金的浸出率可达89.93%。最终矿石在“浮选-焙烧-水洗-氰化”的联合工艺下,可使矿石中的金得到较好回收。

低品位金矿工艺矿物学特征和金回收

云南某低品位金矿含Au 0.69 g/t,富集难度大。采用化学分析、XRD分析、光学显微镜和扫描电镜等分析手段对该矿石进行了工艺矿物学特征分析,并分别采用浮选、摇床重选和氰化浸出三种方法处理该金矿,探索最佳处理工艺。结果表明,该低品位金矿石Au品位为0.69 g/t,伴生有益元素银的品位低,银不具有综合回收利用价值,有害元素As含量较高(0.16%);矿石主要结构构造为自形-半自形-它形粒状结构、斑状结构、微晶结构等结构构造;矿石中主要硫化矿物为黄铁矿、黄铜矿、方铅矿和闪锌矿,嵌布粒度较细,其他主要脉石矿物为石英、方解石、绿泥石和高岭土等;矿石中的金主要赋存在铜铅锌硫化矿物中,嵌布粒度细,且大部分以类质同象形式存在;三种选别方法相比较,浮选法的效果最好。在此基础上,系统研究了工艺参数条件如磨矿细度、抑制剂、分散剂、活化剂和捕收剂等对金回收的影响,并进行了开路和闭路试验。结果表明:在磨矿细度-0.074 mm占比80.60%、水玻璃1000 g/t、石灰1000 g/t、硫酸铜200 g/t、丁基黄药100 g/t、丁基铵黑药50 g/t、松醇油30 g/t的最佳工艺参数条件下,采用一次粗选、三次精选、三次扫选的混合浮选工艺流程,最终可获得金品位17.70 g/t、金回收率71.87%的金精矿,金回收效果好。