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.     

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.     

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.     

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%.     

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。     

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。     

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.     

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。     

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.     

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。     

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。     

Innovations in beneficiation technology for low grade phosphate rocks

As high grade deposits of phosphate rock are being depleted day by day in the world, future sources will be derived from low grade rocks containing various impurities. Low grade phosphate rocks are not suitable for direct use in acidulation plants unless their tricalcium phosphate (TCP) content is increased to 70% or more, using conventional methods such as crushing, screening, and drying, or some other physical separation process which include washing and desliming. Other special beneficiation techniques may also be applied, such as calcination, flotation and leaching before taking it as feed for the phosphatic industry.Most of the phosphate rocks are of sedimentary origin with low grade phosphate elements and higher levels of impurities. The first challenge to phosphate industry is the reduction of impurities in rock so that it is suitable for the production of phosphatic fertilizers to meet the increasing demand for phosphate and to cover the depletion of more amenable reserves in the world. This article addresses itself to this challenge: it considers the beneficiation methods for low grade phosphate rocks.     

A new route for the beneficiation of low grade calcareous phosphate rocks

The bulk of the world's phosphate reserves is located in sedimentary horizons that contain appreciable amounts of carbonate. During beneficiation of phosphate rocks, huge amounts of oversize phosphate rocks are rejected from crushers. This reject also mostly contains low tricalcium phosphate content and high carbonate content. In this work, various experiments have been carried out to reduce the carbonate content by leaching the ground phosphate rock with dilute formic acid solution in order to get marketable and industrially acceptable phosphate grades. By using this technique, the effect of formic acid concentration, reaction time, process temperature and liquid/solid ratio (vol./wt. basis) have been studied. It was found that upon treatment of the ground rock with formic acid, the P₂O₅ percent can be raised by up to 29% corresponding to a reduction of about 69% in the calcium carbonate content of the samples, depending on the reaction conditions as well as nature and size of the raw phosphate particles used for analysis.     

低品位矿石选矿工业试生产报告

为了进一步探讨矿区内低品位矿体矿石的可选性(可能达到的生产指标),2007年6～7月在第二铅锌选矿厂进行了工业性试生产.     

磷资源加工研究进展：1．高硅低品位磷矿的湿法浸取流程

针对磷矿资源贫化的问题,介绍了高硅低品位磷矿湿法浸取的新型二水工艺(CWP)及其中的逆流萃取强化过程,对工业化前景和效益进行了初步分析。研究中用16%P2O5的矿可以获得22%P2O5的磷酸,并可获得高质量的副产品磷石膏,显示了较好的应用前景。     

低温下非离子表面活性剂加速细菌浸出黄铜矿

为了提高中温菌氧化亚铁嗜酸硫杆菌(Acidithiobacillus ferrooxidans)在低温(8～10℃)下浸出黄铜矿的浸出速率和最终浸出率,研究了非离子表面活性剂(吐温-20、吐温.60、吐温-80)加速细菌浸出黄铜矿的作用.通过对浸矿溶液中铜的浸出率以及细菌浓度的测定来评价表面活性剂对氧化亚铁嗜酸硫杆菌浸出效果的影响.研究结果表明:3种吐温类表面活性剂在低温条件下对细菌浸出黄铜矿均有一定加速作用,其中吐温-20的加速浸出效果最好,其最佳添加量为0.01%,经过90天后最终浸出率可达49.87%.     

焦油加工废气吸收系统的改造

通过对焦油加工中废气成分的分析,采取增加洗油冷却器、将折流板改为填料的方法提高了废气回收率;利用风机将未吸收的废气送到加热炉燃烧,使废气达标排放。消除了现场异味,生产环境大为改善。