锰银矿同步浸出锰、银新工艺试验研究

介绍了在H2O2体系中处理锰银矿新方法。针对矿石中锰和银的赋存形式,采用在硫酸溶液中加入H2O2可以实现二氧化锰还原和银氧化同时进行。为了进一步提高银的浸出率,在溶液中加入高锰酸钾,以浸出未被二氧化锰包裹的银。研究结果表明,在最佳浸出条件下,锰浸出率可达到96．71％,银浸出率达85．1％。     

P204从高铝粉煤灰硫酸浸液中萃取除铁

主要针对高铝粉煤灰酸浸液中铁铝萃取分离性能进行研究,通过模拟高铝粉煤灰酸浸液(C(Al3+)=37.1 g/L,C(Fe3+)=5.1 g/L),采用P204+260#溶剂油萃取体系,对组成液中铁铝进行萃取分离,系统研究了P204体积分数、温度、反应时间、溶液初始pH值、相比V(O):V(A)等因素对萃取和反萃的影响,...     

Catalytic decomposition of hydrogen peroxide by ferric ion in dilute sulfuric acid solutions

Hydrogen peroxide decomposition in acidic solutions is catalyzed by the free ferric ion, Fe³⁺. The following rate law for this reaction is determined by the initial rate method in solutions similar to those used for acidicin situ uranium leaching: wherek = 4.3 × 10⁻³ s^°1 at 25 °C. From 25° to 50 °C, the activation energy is 85.6 kJ/mol. The decomposition of hydrogen peroxide proceeds by a particular redox reaction sequence that depends on the ratio of the concentrations of hydrogen peroxide to free ferric ion. The rate law determined here is consistent with the form derived from the redox sequence for the case where the ratio of hydrogen peroxide to free ferric ion concentration is greater than 1.0. The magnitude of the rate constant indicates that the decomposition of hydrogen peroxide may cause rapid loss of this oxidant in leaching solutions containing ferric ion. Formerly a Graduate Student with the Department of Geochemistry and Mineralogy, Pennsylvania State University,     

Kinetics of galena dissolution in nitric acid solutions with hydrogen peroxide

The extraction of lead from a galena concentrate in nitric acid solutions with additional hydrogen peroxide was studied taking stirring speed, temperature, hydrogen peroxide and nitric acid concentrations, and particle size as dissolution parameters. The dissolution curves followed the surface chemical reaction controlled shrinking core model over the whole range of parameters, except at high nitric acid concentrations where the reaction was diffusion-controlled. The activation energy of 42 kJ mol^− 1 and a linear relationship between rate and inverse particle size support the reaction controlled dissolution mechanism. Hydrogen peroxide addition accelerated the reaction compared with nitric acid alone. It was concluded that the dissolution process is favourable, since the acid consumed for oxidation of galena can easily be regenerated in the same reactor by means of hydrogen peroxide.     

铁闪锌矿在硫酸浸出过程中的电化学行为

为研究铁闪锌矿氧化浸出机理,以人工合成铁闪锌矿的悬浮矿浆为研究对象,采用三电极体系对其在硫酸浸出过程中的电化学行为进行了研究.结果表明在铁闪锌矿浸出过程中有H₂S中间产物生成;通氧、元素硫分散剂以及氯离子引入浸出体系均能明显促进铁闪锌矿的电化学氧化;随硫酸浓度升高,铁闪锌矿的电化学氧化不断加强而闪锌矿的电化学氧化受抑.与闪锌矿相比,铁闪锌矿更易发生电化学氧化.在铁闪锌矿硫酸浸出过程中,其电化学氧化作用不容忽视.     

Effect of solution composition on the optimum redox potential for chalcopyrite leaching in sulfuric acid solutions

The leaching rate of chalcopyrite (CuFeS₂) by Fe³⁺ in H₂SO₄ solutions depends on the redox potential determined by the Fe³⁺/Fe²⁺ concentration ratio, and there is a maximum leaching rate at an optimum redox potential. The present study investigated the effects of solution composition on the optimum redox potential by electrochemical measurements using a CuFeS₂ electrode and electrolyte solutions containing 0.01–1 kmol m^− 3 of H₂SO₄, Fe²⁺, and Cu²⁺ at 298 K in nitrogen.Anodic-polarization curves of the CuFeS₂ electrode showed that there was a current peak on the curves in the presence of Cu²⁺ and Fe²⁺, corresponding to the maximum leaching rate. The redox potential of the peak increased markedly with increasing Cu²⁺ concentration, while it was little affected by the H₂SO₄ and Fe²⁺ concentrations. These results agree with the results of leaching experiments reported previously, and indicate that the optimum redox potential for chalcopyrite leaching is a function of the Cu²⁺ concentration. An empirical equation for the optimum redox potential for CuFeS₂ leaching is proposed.     

Kinetics of iridium reduction by hydrogen in hydrochloric acid solution

The effects of stirring speed, initial iridium ion concentration, hydrogen pressure, hydrochloric acid, chloride concentrations, seeding, and temperature on the reduction rate of iridium ion by hydrogen have been investigated. The whole process of reduction occurs in a complicated heterogeneous stage. The reduced metallic Ir serves itself as a catalyst for the reduction. The rate in the earlier stage of the reduction (including the nucleation period) is controlled by chemical reaction; the apparent activation energy obtained in the temperature range of 363 to 423 K was 76.1 kJ/mol. The order of the reaction with respect to the iridium ion concentration and the hydrogen partial pressure was found to be one, and the reaction rate increased with the increase of HC1 and Cl concentrations. The rate in the later stage was controlled by diffusion, and the apparent activation energy was reduced to 25.5 kJ/mol. The reaction mechanism has been given by the analysis of experimental results. Formerly Graduate Student, Department of Extractive Metallurgy, Institute of Precious Metals     

硫化矿的浸金研究—酸性硫脲溶液体系

本文研究了在用酸性硫脲溶液从硫化矿中浸金时,硫酸铁浓度、硫脲浓度、酸度、温度、搅拌速度、浸取时间、矿石粒度及固液比等实验条件对金、银浸出率的影响。并对所得结果进行了讨论。     

Kinetics model for leaching of ion-adsorption type rare earth ores

This paper aims to establish a mathematical model that can analyze the whole leaching kinetics process of ion-adsorption type rare earth ores. This leaching process is composed of three steps: (1) ammonium ions arrive at the ore particle surface through the diffusion layer; (2) ammonium ions exchange with rare earth ions; and (3) rare earth ions enter into the external solution through the diffusion layer. In the leaching process, it is hypothesized that the ore particle size remains constant. The process of ammonium ions and rare earth ions passing through the diffusion layer was described by the Fick law, and the reversible ion exchange process between ammonium ions and rare earth ions was described by the Kerr model. A leaching kinetics model of rare earth ions by ammonium ions was constructed. Accuracy of this kinetics model was verified with laboratory tests. It is found that the correlation coefficients of all data are greater than 0.9000. The proposed kinetics model is therefore feasible for kinetics analysis throughout the leaching process.     

Enrichment of valuable metals from the sulfuric acid leach liquors of nickeliferous oxide ores

The enrichment of valuable metals from sulfuric acid leach liquors of various nickeliferous oxide ores has been investigated. Suitable enrichment processes based on sulfide precipitation and the Na-jarosite process have been tested and proved to be effective for recovering Ni, Co, and Cu from high-magnesium and high-iron pregnant liquors. Once the major impurities of magnesium and iron had been separated from the valuable metals, the resulting concentrated sulfate solutions mainly containing valuable metals (Ni, Co, and Cu) could be used for further metal separations by solvent extraction methods. It is hoped that such sequences may also be applied for the recovery and enrichment of valuable metals from dilute pregnant leaching liquors.     

蛇纹石硫酸法浸出MgO的热力学研究

本文通过对蛇纹石硫酸浸出过程中的热力学计算,分析了浸出MgO过程中各种矿物与酸的反应活性,及温度对各种矿物浸出的影响.结果表明,蛇纹石中主要矿物Mg6[Si_4O_(10)](OH)_8极易与硫酸反应;铁矿物中的FeO、FeO·SiO_2和FeCO_3易与硫酸反应,Fe~(2+)的析出将不利于Mg~(2+)的分离;磁黄铁矿FeS与硫酸有一定的反应;铝矿物Al_2O_3高温时不易与稀硫酸反应,低温时易与稀硫酸发生反应;而Fe_2O_3、黄铁矿FeS_2和黄铜矿CuFeS_2则不会与稀酸反应,它们的存在不影响Mg~(2+)的分离.     

Kinetics of the dissolution of pure silver and silver-gold alloys in nitric acid solution

This article describes a kinetic study of the dissolution of silver and silver-gold alloys in nitric acid. For pure Ag, the nitric acid reaction order is two at low concentrations and one for concentrations above 4 M. When attacking alloys, the reaction order is one and drops to zero when the alloy contains 51.1 pct of silver by weight or less and the nitric acid concentration is 6 M or above. The activation energy is 12.1 kcal/mol in both cases. When the molar fraction of silver is 0.70 or more, the rate of silver dissolution from its gold alloys is controlled by the chemical reaction on the solid surface. When the molar fraction of the silver is less than 0.65 and nitric acid activity and temperature are high, the dissolution is controlled by the outward diffusion of silver nitrate through the undissolved gold layer. The dissolution rate is affected by the composition of the alloy. When the molar fraction of silver is 0.76 or more, the gold atoms are found in the lattice isolated or in pairs and silver atoms may dissolve without difficulty. Between 0.55 and 0.76, the reaction rate decreases quickly when the gold content increases because the atoms make up chains into lattice and this makes the dissolution difficult. When the molar fraction is less than 0.54, the alloy does not dissolve since the gold atoms form continuous surfaces that impede the attack. Former Graduate Students, Department of Metallurgy, University of Barcelona.     

A simple kinetic model for sulfuric acid leaching of copper from chrysocolla

Experimental results obtained in room temperature laboratory leaching studies of lowgrade chrysocolla are interpreted by a kinetic equation of the form 1?(1?R)^1/3=(1/αKr _c) ln (αkKC ₀t+1) derived on the basis of a special form of the shrinking-core model and assuming chemical-reaction control. The experimental program encompasses a large range of particle sizes and reaction times and significantly extends previous experimental data on similar ore systems. The kinetic model, shown to be consistent with the experimental data, assumes the ore-particle structure to be characterized by pores and channelized regions which extend from the outer surface through a reacted zone into the unreacted core. Scanning electron microscope observations of unreacted particle surfaces as well as reacted particle surface structures lend support to this concept of leaching. The reaction rate is observed to vary inversely with initial mean particle radius, and diffusion in any form appears to be negligible by comparison with surface reaction phenomena.     

Kinetics of reductive leaching of manganese oxide ore with molasses in nitric acid solution

The kinetics of reductive leaching of manganese from a low grade manganese ore in dilute nitric acid in the presence of molasses is examined. The rate is controlled by diffusion through the “product” layer composed of the associated minerals. The leaching process follows the kinetic model 1 − 2/3X − (1 − X)^2/3 = kt with an apparent activation energy of 25.7 kJ/mole. It is concluded that the concentration of HNO₃ and molasses as well as temperature are the main factors influencing the leaching rate. The results indicate a reaction order of 1.2 for HNO₃ concentration and 1.9 for molasses concentration.     

Kinetics of vanadium dissolution from black shale in pressure acid leaching

The leaching kinetics of vanadium from black shale in the sulphuric acid-oxygen system is presented. The effects of agitation speed, leaching temperature in the range of 110-150 °C, sulphuric acid concentration, oxygen partial pressure and particle size on the rate of vanadium leaching were determined. The results indicate that the rate is nearly independent of agitation above 200 rpm and increases with increasing temperature, sulphuric acid concentration and oxygen partial pressure. As leaching occurs, there is a progressive dissolution of a vanadium-bearing alumino-silicate phase, while the inert quartz phase assembles onto the mineral surface and remains as an “ash” layer. The leaching kinetics was analyzed by using a new variant of the shrinking core model (SCM) in which both the interfacial transfer and diffusion across the product layer affect the leaching rate. The determined activation energy was found to be 40.14 kJ/mol and the reaction orders with respect to sulphuric acid concentration and oxygen partial pressure were 0.61 and 1.67, respectively. A semi-empirical rate equation was derived to describe the process.     

Kinetic investigation of sulfuric acid leaching of Zn-containing wastes from nonferrous metalworking plants

The kinetics of the dissolution of Zn-containing waste of brass production in sulfuric acid is investigated. It is proved that dissolution proceeds in two stages. Optimal conditions of obtaining zinc sulfate from mentioned waste are found. According to proposed recommendations, zinc vitriol of commercial grade corresponding to GOST (State Standard) requirements is obtained.     

从氯化浸金稀溶液中提取金、银工艺研究

试验采用C410树脂,对氯化浸金稀溶液进行预分离富集,研究了在静、动态条件下C410树脂对金和银的吸附、解吸性能、饱和吸附容量及杂质的干扰等。在试验最佳条件下,对某矿样氯化浸出液,金、银的吸附率分别达99．89％、86．5％,解吸率分别达99．32％、99．72％;解吸液经化学沉淀、溶金银、还原,获得的金、银的纯度达99．995和99．993％。     

Kinetics of hydrochloric acid leaching of smithsonite

The dissolution kinetics of smithsonite ore in hydrochloric acid solution has been investigated. As such, the effects of particle size (−180 + 150, −250 + 180, −320 + 250, −450 + 320 μm), reaction temperature (25, 30, 35, 40, and 45°C), solid to liquid ratio (25, 50, 100, and 150 g/L) and hydrochloric acid concentration (0.25, 0.5, 1, and 1.5 M) on the dissolution rate of zinc were determined. The experimental data conformed well to the shrinking core model, and the dissolution rate was found to be controlled by surface chemical reaction. From the leaching kinetics analysis it can be demonstrated that hydrochloric acid can easily and readily dissolve zinc present in the smithsonite ore, without any filtration problems. The activation energy of the process was calculated as 59.58 kJ/mol. The order of the reaction with respect to HCl concentration, solid to liquid ratio, and particle size were found to be 0.70, −0.76 and −0.95, respectively. The optimum leaching conditions determined for the smithsonite concentrate in this work were found to be 1.5 M HCl, 45°C, −180 + 150 μm, and 25 g/L solid to liquid (S/L) ratio at 500 rpm, which correspond to more than 95% zinc extraction. The rate of the reaction based on shrinking core model can be expressed by a semi-empirical equation as: