Selective and Efficient Extraction of Zinc from Mixed Sulfide–oxide Zinc and Lead Ore

Mixed sulfide–oxide lead and zinc ores are generally composed of both sulfides and oxides. The dissolution of sulfides is more difficult than oxides thus the addition of oxidant is necessary. In this paper, oxidative leaching of mixed ore in NH₃-(NH₄)₂SO₄ solution using ammonium persulfate as oxidant under atmospheric pressure and relatively low temperature was investigated for the first time. The effects of factors on the leaching of pure ZnS were studied and the optimal conditions with zinc 98.7% were determined. Selective and efficient extractions of 93.9% and 94.9% zinc from zinc sulfide ore and mixed ore were also achieved, respectively.     

汤丹氧化铜矿石尾矿在氨水-碳酸铵溶液中的浸出试验研究

研究了云南汤丹高碱性低品位氧化铜矿尾矿在NH3.H2O-(NH4)2CO3体系中的浸出,考察了浸出时间、反应温度、液固体积质量比、总氨浓度及[NH4+]/[NH3]、氧化剂用量、氧化剂添加顺序、氧化时间等因素对铜浸出率的影响,确定了最佳浸出条件。结果表明:最优浸出条件为液固体积质量比10∶1,浸出温度40℃,加入H2O2作氧化剂,用量为0.25mL/g,反应2h;然后添加NH3.H2O及(NH4)2CO3,控制c(NH4+)=3.2mol/L,c(NH3)=0.8mol/L,继续反应4h,铜浸出率达72.3%。     

Dissolution kinetics of malachite in ammonia/ammonium carbonate leaching

The leaching of oxide copper ore containing malachite, which is the unique copper mineral in the ore, by aqueous ammonia solution has been studied. The effect of leaching time, ammonium hydroxide, and ammonium carbonate concentration, pH, [NH₃]/[NH₄⁺] ratio, stirring speed, solid/liquid ratio, particle size, and temperature were investigated. The main important parameters in ammonia leaching of malachite ore are determined as leaching time, ammonia/ammonium concentration ratio, pH, solid/liquid ratio, leaching temperature, and particle size. Optimum leaching conditions from malachite ore by ammonia/ammonium carbonate solution are found as ammonia/ammonium carbonate concentrations: 5 M NH₄OH+0.3 M (NH₄)₂CO₃; solid/liquid ratio: 1:10 g/mL; leaching times: 120 min; stirring speed: 300 rpm; leaching temperature: 25 °C; particle size finer than 450 μm. More than 98% of copper was effectively recovered. During the leaching, copper dissolves as in the form of Cu(NH₃)₄⁺² complex ion, whereas gangue minerals do not react with ammonia. It was determined that interface transfer and diffusion across the product layer control the leaching process. The activation energy for dissolution was found to be 15 kJ mol⁻¹.     

废酸堆浸氧化铜锌矿工艺

本文涉及工业废酸资源化和废弃的氧化铜锌矿资源综合利用的方法。利用废酸堆浸氧化铜锌矿，从浸出液中回收硫酸铜、铁红、铁黄、活性氧化锌及硫酸铵。本法成本低廉，具有经济效益及环保效益。     

高碱性氧化锌矿氨性浸出研究

以NH3—NH4C1体系浸出某高碱性氧化锌矿,考察了氨浓度、液固比、时间和温度等因素对锌浸出率的影响,并分析了相应的浸出过程,得到的最佳实验条件为:NH3:NH4Cl摩尔浓度比为1∶1、氨浓度5 mol/L、液固比为3∶1、浸出时间为2 h、浸出温度40℃,此时锌浸出率为89.3%。     

含碳酸盐脉石氧化铜矿的酸浸动力学

针对碳酸盐脉石对氧化铜矿酸浸动力学的影响进行探讨,研究了温度、酸度、矿石粒径、液固质量比、振荡速度等因素对含碳酸盐脉石氧化铜矿浸出的影响.结果表明,高温、高酸度、高液固质量比、小粒径和高振荡速度利于矿石的浸出,但碳酸盐脉石使得酸耗增加.考虑浸出成本确定合理的浸出条件为温度303 K、酸度35 g·L-1、矿石粒径0.074~0.125 mm、液固质量比3∶1以及振荡速度180 r·min-1,浸出180 min后铜浸出率达53.6%.对浸出前后矿石表面形貌进行分析.结果显示碳酸盐脉石与酸反应后在矿石表面形成CaSO₄·2H₂O沉淀,覆盖在颗粒表面,限制了矿石颗粒孔裂隙的发育.基于收缩未反应核模型对浸出动力学进行分析,发现碳酸盐脉石反应生成的沉淀阻碍了浸出反应,固体产物层扩散为浸出反应的控制步骤,反应的表观活化能为8.65 kJ·mol-1.      

产氨细菌浸出碱性氧化铜矿

采用产氨菌种Providencia JAT-1,对云南某矿高碱性氧化铜矿进行氨浸体系下的摇瓶浸出试验.结果显示温度、矿浆液固质量比、助浸剂种类、助浸剂浓度以及细菌初始接种浓度对铜浸出率具有显著影响.在温度为30℃、矿浆液固质量比7:1、助浸剂硫酸铵浓度0.024 mol·L-1以及细菌初始接种浓度20%的条件下,产氨细菌浸出碱性氧化铜矿144 h后铜浸出率可达42.35%.通过对浸渣铜物相分析发现矿石中次生硫化铜浸出率最高.      

氨法加压浸出钴铜氧化矿工艺

氨法浸出是基于目标金属与氨形成配合离子进入溶液,实现目标金属与部分杂质的分离,因此浸出过程具有选择性。对钴、铜与氨的配合机制及亚硫酸钠还原性能的影响因素进行了分析。结果表明:提高cNH3/cMe有利于形成稳定性高的钴、铜氨配合离子;降低cSO42-/cSO32-,提高体系pH可降低还原剂还原电位。实验过程采用加压氨浸工艺,在NH3-NH4+-H2O体系中浸出钴铜氧化矿中的钴和铜,研究了总氨浓度、氨铵比、液固比、浸出温度、还原剂用量对氧化矿中钴和铜浸出率的影响。结果表明,在总氨浓度7 mol.L-1、氨铵比2∶1、液固比6∶1、浸出温度100℃、还原剂亚硫酸钠用量为三价钴含量(摩尔比)4倍的最优条件下,钴浸出率可达到95.2%,铜浸出率可达到95.8%。浸出液后续处理工艺简单,氨及铵盐可实现闭路循环,对环境友好。     

Principal processing flowsheet of copper–brass wastes of metallurgical brass production

The process flowsheet of dusty wastes forming during metallurgical brass production with the use of two-stage leaching is proposed. The production solution, which contains the main amount of zinc ions (0.46 mol/L) and a small amount of copper ions (less than 0.02 mol/L) is formed at the first stage during the dust dissolution with the 0.5 mol/L sulfuric acid solution. Copper and zinc are sequentially electrochemically isolated from this solution at the current density of 0.1 A/dm² and 5.0 A/dm², respectively. A dry residue (cake) is subjected to copper–ammonia leaching, due to which copper completely transfers into the solution, while accompanying metals remain undissolved. To recover copper from the formed solution, liquid extraction with the solution of 0.34 mol/L DX-510A in kerosene is applied. Copper ions are recovered from the organic phase by reextraction with the 2.0 mol/L sulfuric acid solution. Cathodic copper is isolated from the sulfuric acid electrolyte at the current density of 1.5–2.0 A/dm². The advantages of the proposed flowsheet are an increase in environmental safety due to the use of recirculation of solutions at all process stages, as well as minimization of wastes of the whole process of processing of dusty metallurgical slime.     

Pressure leaching of copper arsenic-containing mattes with copper sulfate solutions

The topicality is shown to improve the processing technology of complex polymetallic raw material containing a considerable amount of toxic impurities of arsenic and lead. Results on pressure leaching the mattes formed after reduction smelting the dusts of OAO Sredneural’skii Copper Smeltery (SUMZ) by solutions of copper sulfate are discussed. These mattes contain a considerable amount of lead and arsenic. According to the data of X-ray phase analysis of matte samples, phases of sulfides (PbS, PbS ? As₂S₃, Cu₂S, FeS, and (Zn,Fe)S) and arsenides (FeAs₂, Cu₃As, FeAs, and Cu_0.85As_0.15), as well as inclusions of metallic copper, are revealed in them. Optimal parameters of matte leaching by copper sulfate solutions are the temperature of 150–180°C, acidity from 5 to 30 g/dm³, and copper concentration of 14–32 g/dm³. This process made it possible to extract 85% As into the solution, while copper and lead remained in the cake in this case.     

Oxidative Pressure Leaching of Silver from Flotation Concentrates with Ammonium Thiocyanate Solution

The thermodynamics and technologies of the selective pressure leaching of silver from flotation concentrates were investigated in an ammonium thiocyanate medium. Thermodynamic analyses, which include silver solubility in NH₄SCN solution and Eh-pH diagrams of the Me-MeS-NH₄SCN-H₂O system at 25 °C, were discussed. The effects of several factors, such as temperature, leaching time, oxidant, pH value, flotation concentrates concentration, surfactant concentration, and so on, on the extraction percentages of silver and zinc were investigated. The following optimal leaching conditions were obtained: NH₄SCN concentration 1.5 M, lignin concentration 0.5 g/L, Fe³⁺ concentration 2 g/L, flotation concentrates addition 200 g/L, and oxygen pressure 1.2 MPa at 130 °C for 3 hours. Under these optimum conditions, the average extraction percentage of silver exceeded 94 pct, whereas the average extraction percentage of zinc was less than 3 pct. Only 7 pct of ammonium thiocyanate was consumed after 4 cycles, which indicated that ammonium thiocyanate hardly was oxidized under these oxidative pressure leaching conditions.     

Investigation of Leaching Kinetics of Copper from Malachite Ore in Ammonium Nitrate Solutions

The production of metallic copper from low-grade copper ores is generally carried out by hydrometallurgical methods. Leaching is the first prerequisite of any hydrometallurgical process. Solutions containing ammonia may allow for selective leaching of the copper from the ore. In this study, the leaching kinetics of malachite, which is an oxidized copper ore, in ammonium nitrate solutions was examined. The effects of some experimental parameters on the leaching process were investigated, and a kinetic model to represent the effects of these parameters on the leaching rate was developed. It was determined that the leaching rate increased with increasing solution concentration, temperature, and agitation speed, as well as decreasing particle size. It was found that the leaching reaction followed the mixed kinetic controlled model, which includes two different leaching processes including the surface chemical reaction (303?K to 323?K [30?°C to 50?°C]) and diffusion through a porous product layer (323?K to 343?K [50?°C to 70?°C]). The activation energies of these sequential steps were determined to be 95.10 and 29.50?kJ/mol, respectively.     

Leaching behaviour of low-grade copper ore in the presence of organic acid

This study investigated the kinetics of copper leaching from malachite ore using formic acid as an organic leaching reagent. The analysis was carried out to determine the effect of the following parameters: particle size, acid concentration, leaching time, formic acid/malachite ratio, reaction temperature and stirring speed. Based on the experimental results, the optimum leaching parameters are as follows: particle size, +75?30?µm; formic acid concentration, 0.4?mol?L^?1; leaching time, 90?min; formic acid (volume)/malachite (weight) ratio, 10?mL?g^?1; temperature, 25°C; and stirring speed, 200?rev min^?1. Copper extraction was 70.25% under optimum experimental conditions. Furthermore, a kinetic model was used to indicate the effects of these parameters on the leaching of copper from malachite ore in formic acid solution. It was observed that the leaching process was controlled by film diffusion through a product layer. In conclusion, formic acid can be utilised as an organic leaching reagent in the leaching process of other ores that are similar in structure and composition to malachite.     

某氧化铜钴矿硫酸浸出试验研究

采用硫酸为浸出剂,对氧化铜钴矿浸出工艺进行了研究。试验结果表明:硫酸加入量为氧化铜钴矿质量的12.5%,氧化铜钴矿粒度磨样-74μm占87%,浸出温度80℃,浸出时间2 h,浸出液固比L/S=2∶1;铜浸出率为89.26%,钴浸出率为78.69%。     

铜锌银精矿冶炼新工艺

介绍了一种处理复杂铜锌银精矿的新工艺。该工艺是利用 SO2 -3 还原浸出液中的 Cu2 ,使生成 Cu2 Cl2 ,而将铜锌有效分离。Cu2 Cl2 经氧化可制取 Cu SO4,铜的总回收率为 94 .2 9% ,硫酸铜平均品位为 96.72 % ,超过 GB4 3 7— 80一级品要求 (96% ) ;沉铜后的溶液经净化后可制取质量分数大于 99.5%的氧化锌产品 ,锌的直收率为 80 .60 % ,总回收率为 86.4 1 % ;浸出渣用高浓度 NH4Cl溶液循环浸出银 ,银总回收率为 94 .70 %。     

Improving the Estimation Accuracy of Copper Oxide Leaching in an Ammonia–Ammonium System Using RSM and GA-BPNN

In this study, a response surface methodology (RSM) model was used to analyze and optimize the factors affecting copper leaching efficiency in a copper oxide ammonia-ammonium (AA) system based on the parameters of AA concentration (ammonium hydroxide and ammonium bicarbonate matched with 1: 1), leaching time, grinding fineness, liquid-solid ratio, and temperature. The RSM analysis showed that five individual variables had a significant influence and that the interaction between AA concentration and leaching time had the most significant influence on leaching efficiency. In order to improve the estimation accuracy of the copper leaching efficiency, a model consisting of a genetic algorithm and a back propagation neural network (GA-BPNN) was used to optimize the operation index. A back propagation feed forward neural network with 3 layers (5–10–1) was applied to predict copper leaching efficiency. The genetic algorithm was applied to analyze the optimal leaching conditions. The results revealed that the GA-BPNN model outperformed the RSM model for predicting and optimizing copper oxide AA leaching. The optimization results of the GA-BPNN resulted in an R² of 0.99827 and the highest predicted copper leaching efficiency of 79.49% was obtained under the conditions of an AA concentration of 4.78 mol/L, a leaching time of 157 min, a grinding fineness of 86.86% (–74 μm content account), a liquid-solid ratio of 2.87: 1, and a temperature of 313.17 K. A prediction and optimization method combining RSM and GA-BPNN, as used in this paper, can be further employed as a reliable and accurate method for ore leaching.     

空气氧化—氨浸出废旧电路板中的铜

提出了在氨水—硫酸铵体系下鼓入空气浸出废旧电路板中铜的新工艺。考察了氨水浓度、硫酸铵浓度、固液比、反应温度、通入空气流量和浸出时间对铜浸出率的影响。结果表明,在下述最佳浸出条件下,渣计铜浸出率达到96.67%:氨水浓度2mol/L,硫酸铵浓度2mol/L,固液比1∶20,反应温度25℃、通入空气量8m3/h、浸出时间4h。     

Separation of zinc from spent zinc-carbon batteries by selective leaching with sodium hydroxide

Physical methods such as crushing and sieving followed by magnetic separation steps were applied to separate non-magnetic material (88.4 wt.%) from zinc-carbon spent batteries. The oversize material was processed by eddy current separation to recover zinc sheet, carbon rods, and plastics. The undersize fraction (− 2.36 mm) with a metal composition of 15.5% Zn, 17.5% Mn, and 1.4% Fe was used for the leaching experiments under different conditions such as concentration of sodium hydroxide, temperature, agitation speed, and pulp density. Selective leaching using 4 mol dm^− 3 NaOH at 100 g dm^− 3 solid/liquid ratio, 80 °C and 200 rpm gave a zinc extraction of 82% and a manganese extraction of less than 0.1%. An overall zinc recovery was about 88.5% by the processes described in this study.     

从含砷钼矿浸出液中脱砷

采用砷酸铵镁沉淀法对含砷钼矿的浸出液进行了脱砷研究。理论分析得到脱砷过程中浸出液pH=10、浓度为0．1moL／L时，溶液中砷浓度为3．2×10^-8mol／L。试验研究了pH值大小、NH4Cl、MgCl2用量对浸出液脱砷率、钼入渣率以及钼砷比（Mo／As）的影响。找到了脱砷的最佳试验条件，在该条件下砷的脱除率可达到99．71％；钼入渣率可降至2．36％；Mo／As可达8697．82，实现了含砷浸出液中砷的脱除。     

Hydrothermal Sulfidation and Flotation of Oxidized Zinc-Lead Ore

The sample with smithsonite and cerussite as the main valuable metal minerals is a carbonate-hosted lead-zinc ore in the current study. Hydrothermal sulfidation of oxidized zinc-lead ore was carried out with a particle size of 74 to 58 μm and the mole ratio of sulfur and zinc of 2.0 at 453 K (180 °C) for 240 minutes, and 73 pct zinc and 86 pct lead sulfidation fraction were achieved. Flotation of the unsulfided sample was ineffective, with less than 55 pct recovery of zinc and lead. After sulfidation, the recoveries of zinc and lead in flotation concentrate were over 92 pct. A flotation concentrate was obtained with zinc and lead content of 41.2 pct and 22.1 pct, respectively.