Copper solvent extraction from alkaline cyanide solution with guanidine extractant LIX 7950

The use of the guanidine extractant LIX 7950 extracting copper and cyanide from alkaline cyanide solution was investigated.The extraction of copper and cyanide under different initial copper and extractant concentrations was examined and the stoichiometric extraction constant of Cu(CN)32- with LIX 7950 was calculated.Both the distribution coefficient and the stoichiometric extraction constant of Cu(CN)3 2-with LIX 7950 decrease when the temperature is varied from 25℃to 45℃, indicating the extraction process is exothermic.The calculated enthalpy change of the reaction(-HΘ)is about-190 kJ/mol.The copper extraction isotherms under different molar ratios of cyanide to copper are established.The preferential extraction of Cu(CN)32- over Cu(CN)4 3-and CN -has been confirmed and a high cyanide-to-copper molar ratio tends to suppress copper loading. The loaded copper and cyanide can be stripped efficiently by the moderately strong NaOH solutions(0.5-1.0 mol/L)and the presence of NaCN in the stripping solution facilitates copper stripping.

Enrichment of copper and recycling of cyanide from copper–cyanide waste by solvent extraction

The enrichment of copper from copper–cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components, aqueous pH values, temperature, inorganic anion impurities, CN/Cu molar ratio, and stripping reagents, were examined systematically, and the optimal conditions were determined. The results indicated that copper was effectively concentrated from low-concentration solutions using Aliquat 336 and that the extraction efficiency increased linearly with increasing temperature. The aqueous pH value and concentrations of inorganic anion impurities only weakly affected the extraction process when varied in appropriate ranges. The CN/Cu molar ratio affected the extraction efficiency by changing the distribution of copper–cyanide complexes. The difference in gold leaching efficiency between using raffinate and fresh water was negligible.

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.

Synthesis,Structure and Luminescence of a 1-D Chain of Copper(Ⅰ) Cyanide Decorated by Triphenylphosphine

A new wave-like infinite chain coordination polymer [Cu3（CN）3（PPh3）4]n（1,PPh3=triphenylphosphine） has been synthesized by solution reaction and characterized by X-ray single-crystal structure diffraction analysis.The complex crystallizes in space group P1 with a=13.343（6）,b=13.429（7）,c=20.694（10）A,α=103.163（4）,β=96.704（5）,γ=101.981（6）o,V=3479（3）A^3,Z=2,C75H60Cu3N3P4,Mr=1317.76,Dc=1.258 g/cm^3,F（000）=1356,μ=1.043 mm^-1,the final R=0.0680 and wR=0.1305 for 9232 observed reflections with I〉2σ（I）.The infinite chain is linked by C-H…π H bonding interactions to form a 2-D supramolecular network.Luminescent study reveals that the complex has green-light emission.

Copper and Cyanide Recovery in Cyanidation Effluents

Cyanidation is the main process for gold and silver recovery from its ores. In this study, a process is proposed to recover copper and cyanide from barren solutions from the Merrill-Crowe cementation process with zinc dust. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 97 and 99%, when copper concentration in the influent was 636 and 900 ppm. respectively. In this process (sulphidization-acidification-thickening-HCN recycling), the cyanide associated with copper cyanide complexes, is released as HCN gas under weakly acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide. Cyanide recovery was 90%. Finally, this procedure was successfully run at Minera William in México.

Copper Recovery from Barren Cyanide Solution by Using Electrocoagulation Iron Process

This paper is a brief overview of the role of inducing the nucleated electro winning of copper by using iron electrodes in electrocoagulation (EC) process. Cyanide compounds are widely used in gold ore processing plants in order to facilitate the extraction and subsequent concentration of the precious metal. Owing to cyanide solution employed in gold processing, effluents generated have high contents of free cyanide as well as copper cyanide complexes, which lend them a high degree of toxicity. In this regard, two options for the treatment of cyanide barren solutions has been used;in two ways;first for cyanide destruction by oxidation with the use of the EC process, in theory, has the advantage of decomposing cyanide at the anode and collecting copper simultaneously by a sludge of copper magnetic iron. In both cases excellent performance can be achieved using the high capacity of the bipolar iron EC technology. We found that it is possible to reduce the copper cyanide complex from 720 mg·l-1 to below 10 mg·l-1 within 20 minutes.

Application of ferrate(VI) in the treatment of industrial wastes containing metal-complexed cyanides : A green treatment

Ferrate（VI） was employed for the oxidation of cyanide （CN） and simultaneous removal of copper or nickel in the mixed/complexed systems of CN-Cu, CN-Ni, or CN-Cu-Ni. The degradation of CN （1.00 mmol/L） and removal of Cu （0.095 mmol/L） were investigated as a function of Fe（Ⅵ） doses from 0.3-2.00 mmol/L at pH 10.0. It was found that Fe（Ⅵ） could readily oxidize CN and the reduction of Fe（Ⅵ） into Fe（Ⅲ） might serve efficiently for the removal of free copper ions. The increase in Fe（Ⅵ） dose apparently favoured the CN oxidation as well as Cu removal. Moreover, the pH dependence study （pH 10.0-13.0） revealed that the oxidation of CN was almost unaffected in the studied pH range （10.0-13.0）, however, the maximum removal efficiency of Cu was obtained at pH 13.0. Similarly, treatment was carded out for CN-Ni system having the initial Ni concentration of 0.170 mmol/L and CN concentration of 1.00 mmol with Fe（Ⅵ） dose 2.00 mmol at various pH values （10.0-12.0）. Results showed a partial oxidation of CN and partial removal of Ni. It can be observed that Fe（Ⅵ） can partially degrade the CN-Ni complex in this pH range. Further, Fe（Ⅵ） was applied for the treatment of simulated industrial waste/effluent waters treatment containing CN, Cu, and Ni.

Activation of Nitromethane to Cyanide by a Mononuclear Cu(Ⅱ) Complex

The tridentate ligand DPA-Me（2） was readily prepared from DPA（DPA = 2,2-dipicolylamine） in high yield. The mixture of 2 and Cu（ClO4）26H2O in methanol gave a five-coordinated mononuclear complex [（DPA-Me）Cu（Me CN）（ClO4）]（ClO4）（3）. Recrystallization of 3 in CH3NO2 led to an activation of CH3NO2 to CN- by the formation of product as a dinuclear cyanide bridged complex {[Cu（DPA-Me）]2（CN）（ClO4）3CH3NO2}n（4）. Both 3 and 4 were characterized by X-ray crystallography, IR spectroscopy and elemental analysis. The crystal of 4 was grown in space group P21/c with a = 17.74582（15）, b = 13.89877（11）, c = 14.92546（13） A, β = 91.4246（8）°, V = 3680.15（5） 3, Z = 4, Dc = 1.695 g/cm^3, F（000） = 1912, C28H33Cl3Cu2N8O14, Mr = 939.05, μ = 1.602 cm^-1, Cu Kα radiation（λ = 1.54184 ）, R = 0.0485 and w R = 0.1246 for 6414 observed reflections with I 〉 2σ（I）.

络合沉淀法—硫化沉淀法联合处理铜氰贫液试验研究

针对某黄金生产企业产生的铜氰贫液,采用络合沉淀法—硫化沉淀法联合进行回收处理。在络合沉淀法五水合硫酸铜投加量3.0 g/L、焦亚硫酸钠投加量2.0 g/L,硫化沉淀法九水合硫化钠加药量0.35 g/L条件下,铜氰贫液中总氰化合物、铜和硫氰酸盐质量浓度从150.84 mg/L、121.46 mg/L、252.65 mg/L降至0.44 mg/L、86.17 mg/L、1.23 mg/L,回收金、银、铜的产值为116.62元/m^(3),扣除药剂成本后产生经济效益55.44元/m^(3)。研究结果为类似氰化企业铜氰贫液的净化处理提供参考。

中亚某难选含铜金矿选冶试验研究

采用“浮选—浮选精矿销售—浮选尾矿直接炭浆法氰化浸出”工艺综合回收中亚某矿山过渡带难选含铜金矿中的金和铜。矿石含金3.52g/t、银11.20g/t、铜0.54%、砷0.40%、硫1.54%,其中氧化铜含量为0.22%,占总铜含量的40.74%,金、铜嵌布粒度微细,嵌布关系复杂,属于复杂难选含氧化铜金矿。针对矿石特点,通过引进氧化铜矿石的捕收药剂体系,增加精选级数,按照便于现场技改的硫化铜、氧化铜混合浮选工艺进行金铜浮选回收,对铜浮选尾矿进行直接炭浆法氰化浸出回收金,最终可获得产率3.92%,含金48.50g/t、含铜8.45%的浮选精矿,可直接销售;浮选尾矿含铜0.21%,可氰化铜含量为0.12%,将其直接炭浸消耗氰化钠3.1kg/t,金浸出率达到74.71%;浮选+浸出金综合回收率为88.26%,铜回收率为62.16%。与现场“浮选—浮选精矿销售—浮选尾矿氨氰法抑铜浸金—氨氰尾浆炭浸”工艺相比,浮选精矿产率接近,精矿金铜品位更优,金综合回收率提高了6.02个百分点,铜回收率提高了9.24个百分点。研究结果可作为现场技改依据。

预浸对烧结钕铁硼HEDP电镀铜的影响

[目的]烧结钕铁硼(Nd Fe B)的电镀前处理技术还不够成熟,开发适宜的前处理工艺极其重要。[方法]在电镀铜前,先采用以羟基乙叉二膦酸(HEDP)为主配位剂的溶液对NdFeB进行预浸。预浸液组成和工艺条件为:HEDP 20~30 g/L,氢氧化钾20~25 g/L,碳酸钾10~15 g/L,葡萄糖酸钾1~2 g/L,乙酸0.5~1.0 g/L,室温,时间60 s。通过电化学测试对比了Nd Fe B基体有无预浸处理时,铜在其表面的电沉积行为,并通过金相显微镜、扫描电镜、能谱仪和荧光光谱测厚仪,对比了有无预浸处理的Nd FeB基体表面Cu镀层的宏观和微观表面形貌、截面形貌、元素分布及厚度分布均匀性。[结果]Nd Fe B基体预浸后表面被活化,静态电位降低。预浸液能够填满基体表面的孔隙并形成一层水薄膜,在后续电镀铜时保护基体不被腐蚀。预浸处理的Nd Fe B基体表面所得Cu镀层均匀、致密,不易氧化发黑,结合力和耐蚀性较好。[结论]对烧结钕铁硼进行预浸处理,能够保证其在后续电镀铜过程不被腐蚀,提高Cu镀层的综合性能。

哥伦比亚某含铜金矿石选冶过程优化生产实践

哥伦比亚某黄金矿山以含铜高的金矿石为主,技术改造后金回收率低,氰化钠消耗量大,系统中铜离子不断累积,选冶系统生产异常。通过相关试验研究与生产实践,将铜精矿产率从0.25%调整至0.75%,铜浮选金、铜作业回收率分别从20%、34%提高至35%、52%左右,金总回收率从87%提高至89%。将浸出时间从85.48 h减少至56.61 h,氰化钠浓度从1000 mg/L降低至600 mg/L左右,氰化钠消耗量从7.49 kg/t降低至3.60 kg/t,铜浸出率由27.18%降低至20.09%。根据双氧水破氰除铜试验研究,生产中通过焦亚硫酸钠、双氧水配合使用,进行高碱条件处理,破氰排矿铜离子含量从330.47mg/L降低至24.55mg/L,系统铜离子大幅降低。生产实践结果表明:对于哥伦比亚某含铜金矿石采用提高铜浮选回收率,优化浸出条件降低氰化钠消耗,进行双氧水破氰,高碱除铜可以取得较好的生产效果,对同类型的含铜金矿石选冶工艺优化及生产实践具有指导意义。

航空发动机零件环保无氰镀铜工艺

[目的]寻求适用于航空发动机的无氰镀铜工艺,适应绿色环保的发展需求。[方法]从阴极电流效率、深镀能力、均镀能力和沉积速率几个方面对比分析了无氰镀铜溶液和氰化物镀铜溶液的性能,并通过比较镀层外观、结合力、防渗性能和氢脆性,验证了无氰镀铜层的优越性能。[结果]无氰镀铜溶液的上述性能都与氰化物镀铜溶液相当,所得Cu镀层的各项性能均满足航空标准HB/Z 5069–2011的要求。[结论]本研究的无氰镀铜工艺可替代氰化物镀铜工艺,可用于航空发动机零件制造。

氰渣有价金属浮选回收试验研究与应用

为提高氰渣的资源利用率,解决氰渣中有价金属浮选精矿品位不高、回收率低的问题,开展了氰渣性质分析及回收铜、铅、锌的试验研究。根据试验研究结果,结合现场实际情况进行了工艺优化改造和药剂制度调整,生产实践表明:采用铅优先浮选—浮铅尾矿选铜工艺流程,在铅浮选活化剂ZJT用量3000 g/t、捕收剂乙硫氮用量100 g/t,铜浮选活化剂ZJT用量2500 g/t、捕收剂ZJB-2用量100 g/t,浮选流程均为一次粗选两次精选两次扫选的条件下,可以获得铅精矿铅品位22.32%、铅回收率45.76%,锌品位14.47%、锌回收率31.78%,铜精矿铜品位15.38%、铜回收率42.22%的良好指标。改造后,铅精矿铅、锌品位合计提高8~40百分点,铜精矿铜品位提高3~13百分点。

某金矿氰化尾渣铅、铜浮选流程考察及调整

经流程考察,铜、铅浮选均出现精矿品位低、回收率低的问题,根据现场实际情况,结合各个指标数据,将铅浮选将精一尾矿与扫二精矿合并后一起返回到扫一作业,在扫选作业设置补加药剂点,增加硫化铅矿物的浮选时间;使用ZnS对铜、锌、铁进行抑制,扩大与铅的可浮性差异,提高铅精矿的品位。铜浮选作业使用复合药剂,添加抑制剂,精选尾矿与扫二精矿合并后一起返回到扫一作业,扫二作业设置补加药剂点,适量增加返回流程的中矿的质量。调整后铅精矿品位提高至21.98%,铅的回收率提高至45.28%,满足生产要求。铜浮选调整后铜精矿品位提高至10.51%,铜的回收率提高至65.19%,满足生产要求。

ENHANCING GOLD EXTRACTION FROM COPPER BEARING ORES

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Synethesis and Crystal Structure of Bi(ethylenediamine)copper Tetracyanonickelate(II)

The crystal structure of the title compound C 8H 16 CuN 8Ni has been determined by single crystal X ray diffraction. The crystal is triclinic with space group P1, a=6.494(3), b=7.270(4), c=7.936(5) , α=106.67(3), β=91.33(4), γ=106.80(6)°, V=341.3(3) 3, Z=1, M r=346.54, F(000)=177, μ =2\^933mm -1 , D c =1.686 Mg/m 3. The final R factor is 0.0603 for 1214 unique observed reflections 〔 I≥2σ(I) 〕. The structure consists of 〔Cu(en) 2〕 2+ (en=ethylenediamine) cations and 〔Ni(CN) 4〕 2- anions linked together by two of the CN groups (the remaining two act as unidentate ligands) to form infinite chains, in the chain, the hydrogen bonds of N(4)…H-N(5) exist,with distance 3.148 , at the same time the hydrogen bonds of N(4)…H-N(7a) and N(5)-H…N(1a) (a: x-1,y-1,z-1 ) between the interchains also exist, with distances of 3.160 and 3.124 , so it forms a three\|dimensional structure of the title compound.

HEDP镀铜溶液中聚乙二醇6000含量的测定

采用碘沉淀-分光光度法对羟基乙叉二膦酸(HEDP)镀铜溶液中聚乙二醇6000含量的测定进行了研究。结果表明:HEDP镀铜溶液中铜离子会与碘反应干扰测量结果,采用草酸屏蔽铜离子后,可以准确测定HEDP镀铜溶液中聚乙二醇6000含量,标准回收率为98.08%~99.12%,加标回收率为98.24%~98.80%,测定方法误差满足生产控制要求。

SART法和配合沉淀法脱除氰化贫液中铜氰的对比研究

针对某黄金生产企业铜硫分离浮选后硫精矿氰化产生的氰化贫液,分别采用SART法与配合沉淀法净化处理,对比研究了2种方法的铜与氰化物的脱除效果及回收沉渣中铜、金的经济效益。结果表明:贫液中铜、金、氰化物和硫氰酸盐质量浓度分别为121.46、0.12、150.84、252.65 mg/L时,采用SART法时在溶液pH=5、硫铜物质的量比2∶1条件下,滤液中铜、总氰化物质量浓度为1.52、99.72 mg/L,沉渣中铜、金质量分数分别为65.26%、10.56 g/t;采用配合沉淀法时,在铜离子与亚硫酸根物质的量比1.25∶1、铜离子与氰化物与硫氰酸盐之和物质的量比2∶1条件下,滤液中铜、总氰化物质量浓度为22.08、0.77 mg/L,沉渣中铜、金质量分数分别为51.26%、86.53 g/t;相较SART法,配合沉淀法回收有价金属经济效益更高,更适于回收含铜氰化贫液中的铜和氰化物。

络合沉淀法净化处理铜氰贫液

针对某黄金生产企业产生的氰化贫液,采用络合沉淀法用复配亚铜溶液对贫液进行净化处理,考察初始pH值、硫酸铜与亚硫酸钠加药量对氰化物和铜离子去除效果的影响。采用BBD试验设计和响应面法建立贫液中氰化物和铜离子剩余含量的响应面方程。通过对数学模型进行求解得知,在硫酸铜和亚硫酸钠投加量分别为3.01 g/L和2 g/L的条件下,处理后贫液中氰化物和铜离子浓度同时达到最低值,分别为0.38 mg/L和61.94 mg/L,响应面法的预测值与试验值吻合较好,所建模型的可信度较高。对处理后的贫液过滤后调节pH值至10,除去剩余的铜离子,铜离子、氰化物和硫氰酸盐浓度分别达到7.26、0.35和1.42 mg/L,达到回用于生产流程的条件要求。