Removal, Recovery and Recycle of Gold (III) from Aqueous Solution Using Persimmon Tannin Gel

In order to recover much amount of gold, gold removal-recovery cycle was examined using immobilized persimmon gel, which could remove much amount of gold (III) from the tetrachloroaurate solution at 30°C. Removal of gold has proceeded different 2 mechanisms stages. At first, gold (III) was adsorbed rapidly on the surface of the persimmon gels until 2 hours and reached adsorption equilibrium. After that, the amount of gold removed was re-increased slowly and also reached equilibrium until 48 hours. The amount of gold removed was affected by the pH of the solution. The amount of Au removed was the highest at pH 5, which was decreased with decreasing or increasing the pH of the solution. The amount of gold removed (mol/g-dry wt. gels) was increased with increasing the gold concentration in the solution, whereas gold removed ratio was decreased. Gold removed ratio was increased with increasing the amount of persimmon gel used, whereas the amount of removed Au (mol/g-dry wt. gels) was decreased. Gold removal-recovery cycles were also examined in detail.

An Application of Microwave Pre-oxidation in Improving Gold Recovery of a Refractory Gold Ore

Microwave radiation was employed as a pretreating technology to oxidise a refractory gold ore. Heating characteristics showed that, in an identical microwave field, the bulk temperature of the sample increased with microwave power, microwave radiation time and particle size. The rate of sulphur removal increased with microwave radiation time. Particle size also had a significant effect on the oxidation rate. Pyrite and marcasite could be oxidised into Fe 2O 3 with a high porous structure. When microwave radiation was carried out in a rotary bed, the oxidation was more uniformly developed, in comparison with in a fixed bed. Gold extraction by cyanidation could be remarkably improved after the ore was subjected to microwave radiation. The results showed that gold recovery could be improved from 37% to 69%～ 81.2 %.

Activated Hard Shell of Apricot Stones： A Promising Adsorbent in Gold Recovery

Activated carbon has been proven to be an effective adsorbent for the recovery of a wide variety of metal ions from aqueous solutions. In this research, the activated hard shell of Iranian apricot stones was used for gold recovery from electro-plating wastewater. The effect of parameters such as dose and particle size of adsorbent,pH, agitation speed of mixing on the gold recovery was investigated. The results showed that under the optimum operating conditions more than 98% of gold ions were adsorbed onto activated carbon after just 3 h. In addition, the adsorbed gold could be eluted from this adsorbent by improved striping method. The process involves contact of gold-laden adsorbent with a strong base at ambient temperatures followed by elution with an aqueous solution containing an organic solvent. It was found that activated hard shell of apricot stones has the potential to replace im ported commercial activated carbons in gold adsorption processes.

Comprehensive recovery of gold and base-metal sulfide minerals from a low-grade refractory ore

The comprehensive recovery of small amounts of valuable minerals such as gold and base-metal sulfide minerals from a low-grade refractory ore was investigated. The following treatment strategy was applied to a sample of this ore： gold flotation-gold concen- trate leaching-lead and zinc flotation from the gold concentrate leaching residue. Closed-circuit trials of gold flotation yielded a gold concen- trate that assayed at 40.23 g·t-1 Au with a recovery of 86.25%. The gold concentrate leaching rate was 98.76%. Two variants of lead-zinc flotation from the residue--preferential flotation of lead and zinc and bulk flotation of lead and zinc--were tested using the middling processing method. Foam from the reflotation was returned to the lead rougher flotation or lead-zinc bulk flotation, whereas middlings from reflotation were discarded. Sulfur concentrate was a byproduct. The combined strategy of flotation, leaching, and flotation is recommended for the treatment of this kind of ore.

Sorption Recovery of Gold Thiosulphate Complexes

The gold sorption from thiosulphate solutions on carbon sorbents and on anion exchangers was studied. It was shown that the anion exchangers AV-17-10P and AP-100 are the most effective and selective at pH=5-8. These anion exchangers can be recommended for the gold recovery from the industrial solutions.

Kinetic studies of gold recovery from dilute aqueous solutions using Fe^(2+) chloride ions

The kinetics of Au3＋ chloride complex ions reduction using Fe2＋ chloride ions was investigated by stopped-flow method. The influence of initial concentrations of Au3＋ chloride ions, Fe2＋ ions, chloride ions, neutral salt （NaC104）, pH of the solution and temperature was investigated. Activation energy was determined to be 42.36 kJ/mol. Moreover, the kinetic equation was postulated. Obtained solid phase was analyzed using SEM techniques. Particles size varies in the range from 0.5 to 5 gm. It was shown that gold can be removed from the solution by the reduction ofAu3＋ chloride ions and filtration of precipitant.

Removal and Recovery of Chromium(III) from Aqueous Chromium(III) Using <i>Arthrobacter nicotianae</i>Cells

The removal of Cr(III) from aqueous Cr(III) using Arthrobacter nicotianae cells was examined. Cr(III) removal was strongly affected by the pH of the solution and the amounts of Cr(III) removed increased as the pH (1 - 5) of the solution increased. The removal of Cr(III) using the cells was also strongly affected by the Cr(III) concentration of the solution, and obeyed the Langmuir isotherm. The percentage of Cr increased as the cell quantity increased, whereas the amount of Cr (μmol/g dry wt. cells) decreased. The removal of Cr(III) using the cells was very fast, and reached an equilibrium within 6 h from the supply of Cr(III) in the solution. A small amount of Cr(III) absorbed by immobilized cells was desorbed at 30oC;however, most was desorbed at reflux temperature using diluted HCl. Cr(III) adsorption-desorption cycles can be repeated 5 times using immobilized cells. These results have practical implications for industrial wastewater management.

Removal of Chromium(VI) from Aqueous Solution Using Persimmon Tannin Gel and Subsequent Recovery as Chromium(III)

This study herein was investigated the removal of chromium(VI) from an aqueous solution using persimmon tannin gel and its subsequent recovery as chromium(III). At pH 2, Cr(VI) was effectively adsorbed (~80% adsorption) and ppm solution was reduced to Cr(III) on the persimmon gel within 10 min. Although desorption of the Cr(III) species was challenging at 30°, it was increased upon increasing the temperature and was quantitatively desorbed in the presence of 1 M hydrochloric acid under reflux. In addition, although the quantity of retained Cr(VI) on the tannin gel increased upon increasing the chromium concentration of the original aqueous solution, all the desorbed chromium was successfully reduced to Cr(III). Finally, Cr(VI) removal and recovery as Cr(III) was repeated effectively 8 times using the same persimmon tannin gel sample, thus demonstrating the recyclability of this system.

Influence of Copper and Arsenic on Gold Recovery in the Yalea Deposit, Western Mali

Gold recovery process is well known. The following paper presents the problematic related to the influence of Copper and Arsenic on the recovery of gold in the Yalea deposit. Multielement tests (Au, Cu, As) carried out on 37 blocks made it possible to understand that there is a correlation between these elements. This correlation has been observed since the analysis of block models (the block model for Copper, block model for Arsenic and the block model for gold. These models have shown that the Yalea deposit areas with a high gold content correspond to areas of high copper content and arsenic. Those who made it clear that copper and Arsenic are tracing elements of Gold in the Yalea deposit. In this paper, the mineralurgical tests carried out on 28 blocks revealed that the copper and the arsenic content in the ore penalize the recovery of Gold (146 ppm for copper and 4710 ppm for Arsenic). The Yalea deposit was emplaced by several hydrothermal phases that reactivated the structures. These phases are responsible for the establishment of large quantities of copper sulphides. Copper and Arsenic are elements that have a considerable influence on the gold recovery in the Yalea deposit.

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.

硫精矿中有价金属铜金银的综合回收利用实验

这是一篇矿物加工工程领域的论文。对某含铜金银硫精矿进行了选矿综合回收实验研究,实验结果表明,采用异丁基黄药+乙硫氮组合捕收剂,氧化钙做抑制剂,2^(#)油做起泡剂,经过一次粗选-三次精选-二次扫选的浮选工艺流程,最终可得到铜品位为16.66%、回收率为86.96%,金品位为278.95 g/t,回收率为75.56%;银品位为1848.74 g/t,回收率为78.55%的精矿产品,有效地实现了硫精矿中铜的综合回收,同时使金、银很好地富集在铜精矿中,便于回收利用,选矿指标理想。

基于双隐含层BP神经网络的某金矿回收率预测研究

为掌握某金矿选矿工艺影响因素对金实际回收率的作用规律并预测金的回收率,采用正交试验方法开展了金矿浮选试验,通过Pearson系数分析金回收率对不同工艺因素的敏感性,并利用双隐含层BP神经网络对金回收率进行预测。结果表明:生产过程中金回收率对不同因素的敏感性由大到小依次为2#油用量、Na2S用量、丁基黄药用量、CuSO_(4)用量和磨矿细度。在此基础上,选用2#油用量、Na_(2)S用量和丁基黄药用量3个主要影响因素,使用不同隐含层激活函数的BP神经网络对金回收率进行预测。预测结果表明:当使用“logsig”作为激活函数时,其拟合度与精度较高,拟合优度R2为0.9792,相对平均误差仅为0.666%,说明该模型能够较好地预测金回收率。研究结果对贵金属矿山生产中金属回收率的预测有一定的参考意义。

河南某微细粒复杂难选金矿回收金试验研究

河南某金矿石含金1.91 g/t,为主要有价元素,现场经浮选处理后尾矿中仍含金0.43 g/t,有较多损失,为进一步降低尾矿中金的含量,提高金的回收率,对原矿进行了详细的工艺矿物学分析。结果显示,矿石中含金矿物主要为银金矿,载体矿物主要为黄铁矿,脉石矿物主要为石英、长石、云母、白云石等,金的嵌布粒度整体较细,绝大部分在10μm以下,选别难度较大。针对矿石性质,进行了磨矿细度、矿浆pH值、分散剂用量、活化剂用量、捕收剂种类及用量、起泡剂用量等条件试验和金回收的闭路试验。结果表明,在磨矿细度为-0.074 mm占85%、矿浆pH自然状态、分散剂六偏磷酸钠用量为300 g/t、活化剂组合硫酸铜和KDH01用量分别为100 g/t和50 g/t、捕收剂丁基黄药用量为200 g/t、起泡剂MIBC用量为40 g/t的条件下,原矿采用“一次粗选—两次扫选—两次精选”流程,中矿采用循序返回方式,扫选药剂用量依次按粗选药剂用量减半添加,精选不加药,全流程闭路试验最终可获得金品位30.63 g/t、回收率86.28%的金精矿产品,尾矿中金品位降至0.28 g/t,显著提高了金的回收率,回收效果较好,同时,自研活化剂KDH01对该金矿有较好的适用性,增加了矿物表面活性位点,增强了浮选效能,有效指导了实际生产。

贵州某氰化尾渣金回收试验研究

贵州某氰化尾渣含金1.66 g/t,金主要以裸露金和硫化物包裹金的形式存在,氰化尾渣粒度较细,-0.038 mm粒级占比超过80%。针对氰化尾渣含泥量高的特点,采用泥砂分选工艺,通过旋流器分级,对沉砂和溢流分别进行浮选回收。采用一粗二扫三精流程,对沉砂和溢流分别采用适应其特性的工艺参数及药剂制度,泥砂分选全流程闭路试验可以获得金品位12.42 g/t、金回收率50.13%的精矿;氰化尾渣全粒级浮选可以获得金品位9.49 g/t、金回收率38.10%的精矿。结果表明,泥砂分选工艺获得的精矿中金品位提高了约2.9 g/t,金回收率提高了约12百分点,实现了氰化尾渣中金的有效回收。

采用组合捕收剂提高铜精矿中金的回收率试验研究

福建省某铜矿石采用石灰抑硫浮铜过程中,在铜硫分离过程中强压黄铁矿势必造成了金的损失,在不改变原工艺流程的基础上,采用组合药剂丁铵黑药+Y89来加强对金的捕收效果,最终组合捕收剂丁铵黑药+Y89闭路试验结果可获得含铜21.14%、含金2.39 g/t、铜回收率90.22%、金回收率51.36%的铜精矿,比单独丁铵黑药闭路试验指标铜精矿中金回收率提高了4~5个百分点,表明该类型铜矿石添加Y89对金的捕收有较明显的促进作用。

金尾矿综合回收技术研究进展

金矿选别过程中产生的尾矿量逐年上升,长期堆存不仅会占用大量土地资源,还会对环境造成污染,且金尾矿中还残留了金、钨、铁等有价金属矿物以及石英、长石、重晶石等非金属矿物,具有较高的回收利用价值,因此金尾矿的综合回收利用是金矿资源绿色高效开发的重要内容。综述了金尾矿中有价金属矿物(金、铁、钨、锌等)和非金属矿物(石英、长石、绢云母、重晶石等)的回收工艺、药剂种类及药剂制度,指出了各种矿物回收中存在的问题。未来应结合计算机技术加强新型浮选药剂的设计与开发,持续优化工艺流程,提高综合回收率,以实现金尾矿资源的最大化利用。

氰化尾渣中微细粒低品位金回收技术研究与应用

针对某黄金生产企业氰化尾渣选硫生产过程中,微细粒低品位金无法回收利用造成资源浪费情况,开展系统试验研究。以现有氰化尾渣选硫系统为基础,以氰化尾渣及硫精矿为试验对象,进行金回收技术方案条件试验,最终形成氰化尾渣经现有选硫系统进行金、硫富集后,进行旋流器分级生产高金硫精矿和低金硫精矿技术方案。该技术方案成本低、易于工业化实施。现场改造后,产出金品位大于3.0 g/t、硫品位大于46.5%的高金硫精矿和硫品位大于46.5%的低金硫精矿2种产品,最大限度地提高了经济效益。

某微细粒复杂难选金矿尾矿工艺矿物学研究

某微细粒复杂难选金矿原矿中金品位为1.91 g/t,浮选尾矿的金品位为0.43 g/t,金回收率在81.5%左右。为查清尾矿中金的损失状态和制约金回收率的主要因素,提高金的回收率,采用X射线荧光光谱(XRF)、X射线衍射(XRD)、工艺矿物学自动分析仪(BPMA)、扫描电镜-能谱仪(SEM-EDS)等手段对尾矿系统开展工艺矿物学研究。分析结果表明,尾矿中的金矿物主要为银金矿,其次为自然金;金矿物主要以与黄铁矿裸露连生金、黄铁矿裂隙金、黄铁矿与脉石粒间金形式产出,少部分以脉石包裹金形式存在;金矿物整体粒径小,绝大部分分布于1~10μm;金的载体矿物主要为黄铁矿,黄铁矿粒度多小于0.038 mm,单体解离度仅为4.60%;磨矿细度-0.074 mm含量占100%时,裸露金的占有率为55.81%,裸露金中大部分仍然与黄铁矿连生。黄铁矿单体解离度低以及大部分裸露金与黄铁矿连生是金损失的主要原因,通过提高磨矿细度,尾矿中的金才可能得到进一步的回收。但提高磨矿细度回收尾矿中的金时,应注意磨矿均匀度,在保证金及载体矿物尽量单体解离的同时,防止矿石泥化。

分金液中金浓度对沉金工序的影响探讨

因某有色冶炼公司采用贵金属品位很低的进口铜精矿为原料,影响了后续铜阳极泥处理系统的贵金属回收。试验考察了终点电位和分金液金浓度对沉金工序的影响,得到较优的终点电位控制为270 mV,且将分金液返回分金工序进行氧化酸浸分金,每年可降低生产成本29.31万元。

新型捕收剂MC在微细粒难选金矿浮选中的应用

河南省某微细粒难选金矿存在金回收率低的问题,急需对原工艺进行优化。烷基胺可在催化剂作用下与反应剂进行主反应,再进行分离、交连、螯合及乳化反应,从而制成新型捕收剂MC。引进MC进行浮选试验及工业试验,通过原矿性质分析,详细掌握金的赋存状态、嵌布特征和粒度特性等,通过实验室浮选试验确定最佳的磨矿细度、MC用量、矿浆pH值和活化剂用量等工艺参数,并与现场捕收剂体系浮选指标进行对比。试验结果表明,使用MC作为捕收剂,金精矿品位由原来的28.09 g/t提高到34.46 g/t,金回收率由84.85%提高到88.31%,回收率提高3.46%,取得良好的技术指标,实现金精矿品位与回收率的同步提升,预计年增加经济效益1300余万元。