Recovery of copper values from bio-heap leaching of low grade Malanjkhand chalcopyrite ore

M/S Hindustan Copper Limited (HCL), India generates large amounts of lean sulfide ores of copper. The current production of lean copper ores in India is 0.55 million tons with ∼0.3% average copper content. Heap-bioleaching of the lean copper ores in 15 and 30 ton scales was undertaken at IMMT, Bhubaneswar. The leaching study showed 0.09% dissolution of copper from the ore body per day. The leach liquor was processed through solvent extraction and electrowinning. Extraction of copper from the actual leach liquor was carried out with 1.5% LIX 622N in kerosene with zero co-extraction of iron. The copper-free raffinate was fed back to the leaching unit. Stripping of copper from the loaded organic was carried out with 180 kg/m³ H₂SO₄. The copper pregnant electrolyte was passed through a carbon column to make it free from entrained organic and was fed to the electrowinning unit. The increase in current efficiency was due to the increase in the concentration of electrolyte. The energy consumption was 1.7 kWh/kg at a flow rate of 4.5 L/h. Smooth and bright sheets of copper of 99.99% purity were obtained.     

铜阳极泥脱铜渣中金、银、钯含量测定

建立了连续测定铜阳极泥脱铜渣中金、银、钯含量的分析方法,并与火试金法进行比较。首先,利用硝酸+乙二胺四乙酸（EDTA）+酒石酸消解铜阳极泥脱铜渣,得到含有银、钯和少量金的消解液,考察了硝酸、EDTA和酒石酸用量对消解效果的影响。结果表明,硝酸、EDTA和酒石酸用量分别为30mL、3mL、1.5g时,消解效果最好。然后,利用王水对残渣进行二次消解,得到含有金和少量银、钯的消解液,考察了王水用量对消解效果的影响。结果表明,王水用量为15mL时即可完成消解。最后采用火焰原子吸收光谱仪测定消解液中的金、银、钯含量。采用本方法测定铜阳极泥脱铜渣,Au、Ag、Pd各元素相对标准偏差均小于1%（n=10）,加标回收率在95.57%～98.70%之间,实验结果准确可靠、重现性好,与火试金法测定结果相一致。     

硫铁矿烧渣回收铜金属的工艺研究

铜陵有色2×400 kt/a硫铁矿制酸装置产生烧渣约600 kt/a,烧渣铁含量不高[w(Fe)≤55%]、铜含量不低[w(cu)≥0.3%].为了回收烧渣中铜等有价金属资源,进行了硫酸直接浸出法试验研究,试验结果表明,硫酸直接浸出法铜金属总回收率可达65%,该工艺铜回收率相对较低、工艺流程复杂,工业应用还需解决萃取剂消耗高、废液处理费用高等问题.同时简述了氯化还原(离析法)、高温氯化挥发-铁球团法回收烧渣中铜等有价金属试验研究.     

Dynamic global feature extraction and importance-correlation selection for the prediction of concentrate copper grade and recovery rate

Large-scale industrial data have brought great challenges to data calculation and analysis. Feature extraction and selection have become one of the research emphases in data mining. To mine the dynamic characteristics of large-scale industrial data, a dynamic global feature extraction (DGFE) method integrating principal component analysis (PCA) and kernel principal component analysis (KPCA) is proposed such that the achieved feature set is not only dynamic but also contains linear and non-linear features. To ensure that the obtained feature set is optimal with the minimum redundancy, a new importance-correlation-based feature selection (ICFS) method is proposed. To verify the validity and feasibility of the proposed methods, the partial least square (PLS) and least square support vector machine (LSSVM) prediction models for the concentrate copper grade and the recovery rate are established. The effectiveness of the proposed methods is verified through data experiments on a copper flotation industrial process.     

Bioleaching of copper from a low-grade chalcopyrite ore

Experiments conducted in this study provide good evidence that the rate of oxidation of chalcopyrite can be increased many fold by the action of the iron-oxidising, chemoautotrophic bacteria, Thiobacillus ferrooxidans. Studies were made between the range 28–48°C and between pH 2.0 and 3.5. The optimum temperature and pH were found to be 35°C and 2.7, respectively. Particle sizes of chalcopyrite ore used in the study were between 60 and 190 μm in diameter. The rate of leaching was found to be directly proportional to the decrease in particle size. Supply of air to the system had a pronounced effect on the leaching of chalcopyrite by T. ferrooxidans. During the same period of 48 days, the conversion of copper obtained was 17.8, 58 and 54.4% in stationary, a shake flask and a percolator system, respectively.     

Reduction of chalcopyrite with copper (I)

In the presence of Cu(I), chalocopyrite is reduced to Cu₂S and Cu₅FeS₄. Electrochemical studies on polished chalcopyrite crystals establish that this reaction is electrochemical in nature and dependent on the redox potential of the copper(II)/copper(I) couple. A sharp decrease in the initial rate of reduction is observed which is attributed to the rapid formation of bornite and diffusion of Cu(I) through a thickening film. Subsequent reaction of bornite to chalcocite is a slow electrochemical reaction with a Tafel slope of ? 162±5mV.     

盐湖铝系提锂吸附剂成型条件的影响研究

铝系锂吸附剂成型颗粒在盐湖卤水提锂工业应用过程中存在吸附容量低、吸附速率慢和吸附剂粉末脱落等问题。基于现有反溶剂法挤压成型工艺,对盐湖铝系提锂吸附剂成型条件的影响进行了系统性研究。实验结果显示吸附剂成型颗粒粒径越小,达到吸附平衡越快,当颗粒直径d<1 mm时,吸附剂颗粒可在24 h左右达到吸附平衡;降低黏结剂浓度可有效加快吸附剂颗粒的吸附速率,但黏结剂浓度过低会导致其对粉末的包裹性下降;吸附剂颗粒的吸附速率与致孔剂添加比例成正比,当致孔剂添加比例为20%时,吸附剂颗粒能在4 h内完成快速吸附阶段,吸附平衡时对察尔汗高镁锂比盐湖卤水中锂的吸附容量可达4.97 mg·g^-1。     

氯化铁浸出废金属回收海绵铜的工艺研究

采用氯化铁选择性浸出工艺对废金属进行综合利用,制备氯化铁及海绵铜。主要考察了废金属浸出、海绵铜洗涤工艺的可行性,并确定浸出工艺的最佳条件。结果表明:在搅拌速度150 r/min、氯化铁溶液质量分数29.91%、浸出剂量为理论量105%、反应温度60℃、反应时间1.0 h的条件下,铁浸出率为94.86%,铜浸出率为3.57%。浸出渣经盐酸溶液洗涤,能有效提高海绵铜的品质。     

低温下氧化亚铁硫杆菌浸出黄铜矿

使用中温菌氧化亚铁硫杆菌(Thiobacillus ferrooxidans)在低温条件(8～10 ℃)下浸出黄铜矿.结果表明:经过90d的低温摇瓶浸出后,在无菌硫酸浸出过程中,黄铜矿可以自发氧化分解,最终浸出率为16.08%;在无菌高铁硫酸浸出过程中,由于Fe3 起到了一定的氧化作用,最终浸出率为21.3%;在有菌浸出过程中,氧化亚铁硫杆菌在低温下的浸出率可达37.96%.氧化亚铁硫杆菌在低温下浸出黄铜矿的最适pH值为2.0,在接种量为10%,矿石粒径为0.16 mm,矿浆浓度为2%时较为适宜.在低温浸出的初始阶段,当添加Fe2 的量为6 g/L时能促进浸出率提高最大,最终可达到53.51%.     

铜工夹具设计

介绍了一种适用大批量加工铜工的专用夹具,结构简单,在各机床间具有较好的互换性能,能提高零件在电火花加工时的定位精度,并减少装夹时间,提高产品精度和生产率,节约铜工材料。本文对该夹具进行了结构分析,并说明了夹具的原理与用途。     

Ethylene recovery from low grade gas stream by adsorption on zeolites and controlled desorption

Carbon dioxide was partially removed from a nitrogen stream, which also contained some ethylene, by adsorption on a 4A (Na-A) zeolite. The treated nitrogen stream was then passed over a 13X (Na-X) zeolite bed upon which ethylene and any remaining carbon dioxide were adsorbed. Ethylene was recovered by desorption at 68 Pa pressure into a slow flow of nitrogen as stripping gas. The ethylene concentration in the extracted gas was extremely dependent on the nitrogen flow-rate, whereas the concentration of carbon dioxide remained practically constant. Thus, it was possible to obtain a gas mixture greatly enriched in ethylene with a reasonably low content of carbon dioxide.     

Bioleaching of copper via iron oxidation from chalcopyrite at elevated temperatures

The effect of elevated temperature on the bioleaching of copper from chalcopyrite (CuFeS₂) via iron oxidation using Acidithiobacillus ferrooxidans under mesophilic conditions was studied. It was shown that temperature tolerant and ore adapted strains of At. ferrooxidans could extract copper significantly better than non-adapted cultures at elevated temperatures. The presence of soluble iron and its oxidative state, as a determining factor in copper leaching were found to be closely related to pH and temperature.     

Ultrasonic-assisted leaching kinetics in aqueous FeCl<Subscript>3</Subscript>-HCl solution for the recovery of copper by hydrometallurgy from poorly soluble chalcopyrite

We studied the ultrasonic effect on the leaching of copper from poorly soluble chalcopyrite (CuFeS₂) mineral in aqueous FeCl₃ solution. The leaching experiment employed two methods, basic leaching and ultrasonic-assisted leaching, and was conducted under the optimized experimental conditions: a slurry density of 20 g/L in 0.1M FeCl₃ reactant in a solution of 0.1M HCl, with an agitation speed of 500 rpm and in the temperature range of 50 to 99 °C. The maximum yield obtained from the optimized basic leaching was 77%, and ultrasonic-assisted leaching increased the maximum copper recovery to 87% under the same conditions of basic leaching. In terms of the leaching mechanism, the overall reaction rate of basic leaching is determined by the diffusion of both the product and ash layers based on a shrinking core model with a constant spherical particle; however, in the case of ultrasonic-assisted leaching, the leaching rate is determined by diffusion of the ash layer only by the removal of sulfur adsorbed on the surface of chalcopyrite mineral.     

A study on acid reclamation and copper recovery using low pressure nanofiltration membrane

In this study, nanofiltration membrane is used to separate proton (H⁺) and copper ions from a ternary ions mixture (H⁺, Cu²⁺, SO₄^2?). The performance of membrane in separating Cu²⁺ and H⁺ was tested under the effect of pressure, concentration and different acid strength (pH). It was found that the H⁺ rejection is independent of the applied pressure. Permeability of solution decreased linearly with the increase of CuSO₄ concentration. In terms of H⁺ rejection, there is a continuous drop in rejection from 0.1 mM CuSO₄ to 10 mM CuSO₄ solution. H⁺ was poorly retained and concentrated in the permeate stream in corresponding to the electro-neutrality requirements, on the other hand, the rejection of copper ion was almost constant with pH. In overall, optimum acid reclamation and copper recovery can be achieved at higher volume flux. A Three Parameters-Combined Film-Extended Nernst-Planck Equation (CF-ENP) model is successfully applied to predict the performance of nanofiltration membrane in separating the ternary ions.     

谈谈涂料产品的高档与低档

作者从如何正确区分涂料产品的高档与低档这个实际问题出发，提出了开发涂料产品要根据国情，防止“过热”现象，要在提高产品质量的前提下向系列化方向发展。     

低品位硼矿生产硼酸硼泥中硼的回收技术

本文对青海大柴旦地区低品位硼矿生产硼酸排放的硼泥中的硼进行了回收,通过加入母液加热搅拌、絮凝沉降、过滤分离、清水洗涤等工序,使排放的硼泥中的B2O3质量分数小于0.2%,滤液返回硼酸生产工序,提高了硼酸收率,减少了资源浪费和环境污染,具有良好的经济和社会效益。     

Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate

Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, X-ray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite (Cu) and pyrite (S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate (AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology (RSM), the interaction between AH, pulp pH and iso-butyl ethionine (Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t^-1 involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing. The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings.     

从含铜电镀污泥中回收铜和铁的工艺研究

为了回收电镀污泥中的有价金属,提出了以含铜电镀污泥为原料,制备硫酸铜和氧化铁红的工艺流程,并确定了从含铜电镀污泥中回收铜和铁的工艺参数。试验采用硫酸浸取含铜污泥,铜和铁的浸取率分别为98.73%,97.91%;采用N902-磺化煤油-硫酸萃取分离体系萃取分离浸取液中的铜和铁,工艺条件为：水相pH为1.5～1.7,萃取剂体积分数为30%,相比O/A=1∶1,反萃液硫酸浓度为4 mol/L。试验结果表明,通过该工艺处理含铜电镀污泥,铜的回收率大于92%,铁的回收率达到88%以上。     

铜冶炼烟气制酸低温位热回收产汽量探讨

介绍了铜冶炼烟气制酸含空气干燥及低温位热回收的干吸工序串酸的典型流程、串酸水平衡和SO₃平衡的物料衡算方法,分析了干燥塔入口烟气温度、不同浓度硫酸产量比例、串至二吸塔的硫酸温度等因素对低温位热回收系统产汽量的影响。在烟气条件一定的情况下,低温位热回收系统的产汽量主要跟补水量及串至二吸塔的硫酸温度有关。补水量与进干燥塔的烟气、空气的含水量与不同浓度硫酸产量比例有关,产w(H₂SO₄)93%硫酸越多,产汽量越多,但当超过低温位热回收系统保持喷淋密度及硫酸浓度恒定的最大补水量时,产汽量保持不变。