Technological conditions and kinetics of leaching copper from complex copper oxide ore

The kinetic behavior of leaching copper from low grade copper oxide ore was investigated. The effects of leaching temperature, H2SO4 concentration, particle size of crude ore and agitation rate on the leaching efficiency of copper were also evaluated. And the kinetic equations of the leaching process were obtained. The results show that the leaching process can be described with a reaction model of shrinking core. The reaction can be divided into three stages. The first stage is the dissolution of free copper oxide and copper oxide wrapped by hematite-limonite ore. At this stage, the leaching efficiency is very fast （leaching efficiency is larger than 60%）. The second stage is the leaching of diffiuent copper oxides, whose apparent activation energy is 43.26 kJ/mol. During this process, the chemical reaction is the control step, and the reaction order of H2SO4 is 0.433 84. The third stage is the leaching of copper oxide wrapped by hematite-limonite and silicate ore with apparent activation energy of 16.08 kJ/mol, which belongs to the mixed control.

Effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores

The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM-EDS. The results indicated that at ambient temperature, the easily leached copper oxide minerals were completely dissolved, while the bonded copper minerals were insoluble. At lukewarm temperature of 40℃, it was mainly the dissolution of copper in isomorphism state. With increasing temperature to 60℃, the copper leaching rate in the adsorbed state was significantly accelerated. In addition, when the temperature increased to 80℃, the isomorphic copper was completely leached, leaving 11.2% adsorbed copper un-leached. However, the copper in feldspar-quartz-copper-iron colloid state was not dissolved throughout the leaching process. Overall, the leaching rates of copper in different copper minerals decreased in the order: malachite, pseudo-malachite > chrysocolla > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite > feldspar-quartz-copper-iron colloid.

Copper Oxide Ore Leaching Ability and Cementation Behavior, Mesgaran Deposit in IRAN

One of the Iranian copper deposits that is located east of Iran and also known as a primeval one in that area is Mesgaran Field. Old mining works have been clearly seen in the area. Iran is located on global copper belt and as a result it has numerous potential areas as copper deposits. The purpose of this study is identifying possible potentialities of copper mining in less developed regions of Iran with basic modern technologies. In this study, laboratory investigations of this field were done on samples via leaching and the cementation method. According to the study purposes, acid concentration, temperature, time and pulp density were selected as the main factors that were tested in leaching studies. Moreover, pH, temperature, time and the amount of iron powder were factors which were tested for copper cementation. Optimum conditions of leaching studies with 99.11% recovery rate were obtained after 120 grams per liter of H2SO4, 80 degrees Celsius, 2 hours and 100 grams per liter of solid to liquid. On the other hand, optimum conditions of cementation by iron powder were resulted at more than 95% with a pH of 3, 45 degrees Celsius, 1 hour and 1.5 times more than the stoichiometric equation of required iron powder amount to precipitate copper.

Agglomeration and leaching behaviors of copper oxides with different chemical binders

The chemical binder is one of the critical factors affecting ore agglomeration behavior and leaching efficiency.In this study,we in-vestigated the effect of the type of binder and mass fraction of the H_(2)SO_(4)solution used on the curing,soaking,and leaching behavior of ag-glomerations.The results revealed that Portland cement(3CaO·SiO_(2),2CaO·SiO_(2),and 3CaO·Al_(2)O_(3))was the optimal binder for obtaining a well-shaped,stable agglomeration structure.A higher extraction rate was achieved when using Portland cement than that obtained using sodi-um silicate,gypsum,or acid-proof cement.An excessive geometric mean size is not conducive to obtaining well-shaped agglomerations and desirable porosity.Using computed tomography(CT)and MATLAB,the porosity of two-dimensional CT images in sample concentrations L1-L3 was observed to increase at least 4.5vol%after acid leaching.Ore agglomerations began to be heavily destroyed and even to disinteg-rate when the sulfuric acid solution concentration was higher than 30 g/L,which was caused by the excessive accumulation of reaction products and residuals.

Recovery prediction of copper oxide ore column leaching by hybrid neural genetic algorithm

The artificial neural network(ANN)and hybrid of artificial neural network and genetic algorithm(GANN)were appliedto predict the optimized conditions of column leaching of copper oxide ore with relations of input and output data.The leachingexperiments were performed in three columns with the heights of2,4and6m and in particle size of<25.4and<50.8mm.Theeffects of different operating parameters such as column height,particle size,acid flow rate and leaching time were studied tooptimize the conditions to achieve the maximum recovery of copper using column leaching in pilot scale.It was found that therecovery increased with increasing the acid flow rate and leaching time and decreasing particle size and column height.Theefficiency of GANN and ANN algorithms was compared with each other.The results showed that GANN is more efficient than ANNin predicting copper recovery.The proposed model can be used to predict the Cu recovery with a reasonable error.

Separation and recovery of copper in Cu-As-bearing copper electrorefining black slime by oxidation acid leaching and sulfide precipitation

A new hydrometallurgical route for separation and recovery of Cu from Cu-As-bearing copper electrorefining black slime was developed. The proposed process comprised oxidation acid leaching of Cu-As-bearing slime and selective sulfide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 ℃ after 4 h with initial H2 SO4 concentration of 1.0 mol/L and liquid-to-solid ratio of 10 mL/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulfide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulfide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 ℃.

Oxidation leaching of copper smelting dust by controlling potential

A study was conducted for metal extraction from copper smelting dust using the oxidation leaching and control of potential technology.The effects of H2O2 dosage,H2O2 feeding speed,initial HCl concentration,leaching temperature,liquid-to-solid ratio and leaching time on metals leaching efficiencies were investigated.The following optimized leaching conditions were obtained:H2O2 dosage of 0.8 mL/g(redox potential of 429 mV),H2O2 feeding speed of 1.0 mL/min,initial H2SO4 concentration of 1.0 mol/L,initial HCl concentration of 1.0 mol/L,leaching temperature of 80°C,initial liquid-to-solid ratio of 5:1 mL/g and leaching time of 1.5 h.Under the optimized conditions,copper and arsenic can be effectively leached from copper smelting dust,leaving residue as a suitable lead resource.The average leaching efficiencies of copper,arsenic and iron are 95.27%,96.82%and 46.65%,respectively.

Use of ionic liquid in leaching process of brass wastes for copper and zinc recovery

Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid （IL） 1-butyl-3-methyl-imi-dazolium hydrogen sulfate （[bmim]HSO4） at ambient pressure in the presence of hydrogen peroxide （H2O2） and potassium peroxymonosulfate （oxone） as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99%for Zn and 24.82%for Cu at a concentration of 50vol%[bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99%of zinc and 82%of copper are leached by the addition of 50vol%H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4.

Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst

CuO was used as a catalyst in the concentrated KOH solution to enhance the leaching of chromium from the chromite ore.The impacts of temperature,KOH-to-chromite ore mass ratio,CuO-to-chromite ore mass ratio,and gas flow rate on the chromiumleaching rate were investigated.The results indicated that CuO played an important role in improving the chromium leaching rate.The leaching rate reached98%after leaching for6h when CuO was applied,whereas it was only60.8%without CuO under thesame reaction conditions:temperature230°C,KOH-to-ore mass ratio6:1,stirring speed700r/min,gas flow rate1L/min.Accordingto the kinetics study,the catalytic oxidation was controlled by surface chemical reaction and the activation energy was calculated tobe15.79kJ/mol when the temperature was above230°C.In contrast,without CuO,the rate-determining step was external diffusionand the apparent activation energy was38.01kJ/mol.

ACTIVATION MECHANISM OF AlCl_3 DURING THE LEACHING OF Cu-Ni ORE WITH FeCl_3

After Cu-Ni ore powder pre-soaked in AlCl3 solution.the leaching ratios of copper andnickel can increase obviously.By X-ray diffraction analyses,electron energy spectrum analysesand electrochemical experiments,it is affirmed that,the activation of aluminum ion includestwo aspects:one is the surface change of the ore by the absorption of hydrolysates,and the oth-er is the change of semiconductor characteristics of the metal sulfides by impurity aluminum ionentering the lattice,so that leaching reactions are accelerated.

Techniques of copper recovery from Mexican copper oxide ore

Mexican copper ore is a mixed ore containing mainly copper oxide and some copper sulfide that responds well to flotation. The joint techniques of flotation and leaching were studied. The results indicate that an ore containing 19.01% copper could be obtained at a recovery ratio of 35.02% by using sodium sulfide and butyl xanthate flotation. Over 83.33% of the copper oxide can be recovered from the railings by leaching in suitable conditions, such as 1 h stirring at a temperature around 25 ℃with a mixing speed of S00 r/min, an H2SO4 concentration of 1.0 mol/L and a mass ratio of the ore-slurry-liquid to solid （mL/ms） of 3. The overall yield of refined ore after flotation and leaching is over 89.18% of the copper, which is much better than sole flotation or leaching. A copper product containing more than 99.9% copper was obtained by using the process： flotation-agitation leaching- solvent extraction-electro-winning.

Extraction of copper,zinc and cadmium from copper–cadmium-bearing slag by oxidative acid leaching process

An intensified oxidative acid leaching of copper–cadmium-bearing slag featuring using high-efficient oxygen carrier, such as activated carbon, was investigated to achieve high leaching rate of valuable metals. The effects of leaching variables, including agitation rate, sulfuric acid concentration, temperature, slag particle size, activated carbon and cupric ion concentration, were examined. It is found that leaching rates of cadmium and zinc both exceed 99 % in a very short time, but for copper, leaching rate of 99 % is achieved under the optimized leaching parameters, which are agitation rate of 100 r·min^(-1), sulfuric acid concentration of 15 wt%, leaching temperature of 80 ℃, slag particle size of 48–75 lm, activated carbon concentration of 3 g·L^(-1),liquid-to-solid ratio of 4:1, oxygen flow rate of 0.16 L·min^(-1),and leaching time of 60 min. The macro-leaching kinetics of copper metal was analyzed, and it is concluded that the inner diffusion is the controlling step, with apparent activation energy of 18.6 kJ·mol^(-1). The leaching solution with pH value of 2–4 can be designed to selectively extract valuable metals without neutralization, and the leaching residue can be treated by prevailing Pb smelting process.

Improving of copper extraction from chalcopyrite by using NaCl

The addition of NaCl in the ammonium persulfate-APS(as an oxidant)leaching was investigated.APS has some advantages compared with conventional oxidants and its standard redox potential(E°)is2.0V.Effect of six parameters such as NaCl concentration,APS concentration,temperature,time,liquid–solid ration(L/S),and stirring speed on the leaching behavior was studied.Results showed that metals extraction increased with increasing of NaCl concentration,APS concentration,leaching temperature(up to333K),and L/S ratio.During oxidative leaching of sulfide minerals,the occurrence of elemental sulfur layer on particle surface is known as primary problem that causes low metal extraction.According to the results,the passivation effect of sulfur layer and low dissolution problems can be eliminated in the presence of chloride ions.Copper and iron extraction yields were obtained as75%and80%,respectively under leaching conditions as follows:APS concentration250g/L;NaCl concentration150g/L;time180min;temperature333K;stirring speed400r/min;and L/S250mL/g.

Copper hydrometallurgy—current status, preliminary economics, future direction and positioning versus smelting

The heap leaching of oxide copper ores with copper cathode recovery by solvent extraction and electro-winning is now well established as a low-cost method of copper recovery. This technology has recently been applied successfully to mixed oxide and chalcocite ores, notably in Chile at Cerro Colorado, Quebrada Blanca and Zaldivar. Currently, there are significant development efforts underway to try to extend heap leaching to chalcopyrite ores. The success of heap leaching/SX/EW has also led to a revival in the development of hydrometallurgical processes to recover copper from chalcopyrite and other copper concentrates. The current status of copper hydrometallurgy is reviewed and the most commercially attractive potential applications are explored. The advantages and disadvantages of the hydrometallurgical treatment of chalcopyrite concentrates and its preliminary economics are compared with those for the current best practices in copper smelting and refining.

Enhanced leaching of copper from refractory oxidized copper ore by calcium fluoride: Behavior and mechanism

The Luanshya area of Zambia is rich in copper oxide resources.However,copper mainly exists in biotite and phlogopite,which presents challenges for efficient extraction.To improve the leaching rate of copper from these ores,local hydrometallurgical plants use heating and stirring;however,the leaching rate is not high.To address the issue in this work,CaF_(2) was introduced as a leaching aid,and the effects of various parameters on leaching were systematically studied.The results revealed that when the dosage of CaF_(2) is 5wt%of raw ore mass,the dosage of sulfuric acid is 120 kg/t,the leaching temperature is 60℃,and the leaching time is 200 min with a slurry concentration of 30wt%,the leaching rate of copper can reach 80.44%.Compared with regular heating stirring acid leaching,the copper leaching rate was found to increase by 8.76%,while the leaching temperature decreased by 5℃ and the leaching time shortened by 40 min.The results of the HSC Chemistry 6.0 thermodynamic calculations and mechanism analysis indicated that F can promote the fracture of si-O and Al-O bonds in the crystal structure of biotite and phlogopite in sulfuric acid solution,enabling a direct reaction between the acid and copper.The proposed method can be applied not only to the treatment of cupriferous mica ores but also to the processing of other copper ores.This process is more efficient and cost-effective than the regular heating-stirring acid leaching process.

刚果(金)某铜钴矿浸出新工艺

这是一篇冶金工程领域的文章。刚果(金)某铜钴矿为氧化矿,铜钴含量分别为Cu 3.43%和Co 0.42%。本文采用浸出液五级循环浸出工艺浸出铜和钴,在硫酸用量为矿石质量的7.4%、亚硫酸钠用量为理论量的1.68倍、磨矿粒度-74μm 75%、浸出温度45℃、浸出液固体积质量比2/1~3/1、单级浸出时间4 h的实验条件下,铜浸出率96.85%、钴浸出率95.67%。该工艺在确保铜钴浸出率的情况下,比一级浸出降低硫酸用量6 kg/t、浸出过程总溶液量减少约1/4,降低了酸耗、减少了后续钴沉淀和铜萃取处理液量。

铜阳极泥中有价元素湿法回收工艺研究进展

我国铜生产量居世界第一,其中80%采用火法冶炼工艺。冶炼过程中产生的铜阳极泥富含Cu、Ag、Au、Se、Te等多种有价元素,具有很高的回收价值。本文分析对比了铜阳极泥的主流处理工艺,其中,湿法工艺作为一种低能耗高效浸出工艺,近些年被广泛地研究。文章系统综述了铜阳极泥湿法处理工艺研究进展,归纳了铜阳极泥氧化浸出、物理强化浸出等预处理方法,总结了铜阳极泥中Cu、Se、Te以及贵金属Ag、Au的回收方法及反应机理。基于当前的研究进展,未来应重点关注湿法工艺的绿色性,开发用于浸出、配合、萃取等过程的绿色试剂,并加强对阳极泥中稀贵金属(Pt、Pd、Rh等)回收的研究,同时需要提升不同元素选择性分离的能力,以获得高纯度产品。

刚果(金)地区超大型铜钴矿资源选冶工艺研究与实践

非洲铜钴矿床主要分布于赞比亚—刚果(金)铜矿带,具有储量大、品位高、矿石性质复杂等特点,这些铜钴矿石按氧化程度与脉石矿物的特性差异,可分为原生硫化铜钴矿石、低钙混合铜钴矿石、高钙混合铜钴矿石、低钙氧化铜钴矿石和高钙氧化铜钴矿石,指出应根据矿石氧化率、脉石矿物的类型(对于碱性脉石矿物必须关注Ca、Mg含量)、矿石中铜钴矿物的赋存状态、金属回收率及加工成本等因素确定其开发利用工艺,并列举了这5类代表性矿石的生产工艺及生产指标。概括说,除低钙氧化铜钴矿石宜采用直接浸出工艺外,其余各类矿石均宜采用选冶联合工艺,但浮选工艺各有特色。研究与生产实践表明,针对不同性质的矿石选用不同的选冶工艺,是获得理想分选指标的关键。

赞比亚卢安夏难浸铜矿石扼酸控杂浸出技术研究

赞比亚卢安夏穆利亚希氧化铜矿石性质复杂,原采用常规加温搅拌浸出工艺处理,但浸出液中杂质离子含量高,影响了后续萃取—电积作业。为实现该矿石的高效清洁利用,开展了分支加酸扼酸控杂浸出试验研究。结果表明:在磨矿细度-200目占70%、硫酸用量45 kg/t、矿浆浓度40%、搅拌强度300 r/min,浸出温度65℃的条件下,对矿石进行常规浸出试验,铜的浸出率为80.35%,铁的浸出率为8.81%,锰的浸出率为39.38%;采用分支加酸工艺,在硫酸用量37.5 kg/t,各段加酸比例分别为30%、25%、20%、15%、10%、0,各段浸出时间均为40 min的条件下,分支加酸浸出试验的铜浸出率为83.29%,铁浸出率为7.78%,锰浸出率为34.86%。与常规加酸工艺相比,硫酸总用量减少了7.5 kg/t,铜的浸出率提高了2.94个百分点,铁和锰的浸出率分别下降了1.03和4.52个百分点;现场应用分支加酸技术,在铜浸出率不低于82%的前提下,吨铜硫酸用量降低0.6 t,浸出液中铁离子和锰离子的浓度分别下降0.75 g/L和0.70 g/L;新工艺在不新增设备和药剂的情况下即可达到提铜降酸控杂的目的,有效降低了吨铜生产成本,提高了料液质量,可为实现同类氧化铜矿的高效清洁浸出提供新的研究思路。

刚果(金)SCM矿区低品位高氧化率铜钴矿浮磁联合选冶试验研究

刚果(金)SCM矿区低品位铜钴矿样中,铜以自由氧化铜、结合氧化铜为主,并含少量次生硫化铜,原生硫化铜甚微;钴主要以水钴矿、菱钴矿、钴白云石等氧化钴的形式存在,铜矿物、钴矿物赋存状态复杂,回收难度大。根据矿石性质和实际生产需求,试验采用“预先浮选硫化矿-硫化浮选氧化矿-磁选-浸出”的原则流程,考察了硫化剂种类、铜钴矿浮选作业药剂制度和磁场强度等因素对铜钴分选指标的影响,考察了常规浸出条件下铜钴的浸出效果。研究结果表明:采用Na_(2)S作为氧化铜钴的硫化剂、丁基黄药为捕收剂、硫化时间4 min时,可实现自然矿浆环境中氧化铜钴的选择性分选;以磁场强度1.1 T、磁场流速1.0 cm/s、磁脉动频率16 Hz为磁选条件,磁选氧化铜钴矿硫化浮选的尾矿,可获得良好的铜钴矿磁选效果。针对含铜1.68%、含钴0.165%、氧化率94.05%的原矿,铜钴矿分选作业采用四段氧化铜浮选、三段氧化钴浮选和两段磁选的开路试验,获得了产率20.99%、铜品位6.67%、铜回收率79.91%、钴品位0.396%、钴回收率51.70%的氧化铜钴粗精矿。对开路试验获得氧化铜钴粗精矿进行硫酸浸出,用98%硫酸调节浸出矿浆酸度,在液固比5∶1、浸出时间4 h、搅拌速度200 r/min、浸出终点pH值约1.5的条件下,铜的浸出率为97.96%,钴的浸出率为91.08%,吨铜净酸为0.96 t酸/t铜。本文的研究结果可为同类型矿石的选冶处理提供一定的技术参考。