本地混合菌群微生物氧化难处理含金硫化精矿（英文）

采用含铁氧化菌和硫氧化菌的混合嗜中温菌群浸出阿根廷Andacollo矿的含金硫化浮选精矿。实验在摇瓶中进行,矿浆浓度为10%,采用pH 1.8的含亚铁离子的基础盐溶液作为介质。采用不同的方法对浸出液的pH值、氧化还原电位、亚铁离子和总金属浓度进行测定。结果表明,该种混合菌能够很好地还原浸出该难处理金矿,金的回收率可达91.6%,同时,铜和锌的浸出率也较高。动力学研究表明金属的溶解符合收缩核模型。其中,铜的溶解速率受生成产物层的扩散控制,而锌的溶解没有明显的控制步骤。     

初始pH对极端嗜热菌万座嗜酸两面菌作用下黄铜矿氧化溶解的影响(英文)

采用生物浸出和循环伏安试验研究初始pH对黄铜矿在65℃条件下氧化溶解的影响,分别采用XRD和拉曼光谱分析黄铜矿生物浸出过程中和电极表面形成的氧化产物。化学浸出结果表明:黄铜矿溶解速率随着初始pH的减小而增大,然而初始pH对黄铜矿生物浸出的影响却正好相反。当初始pH为1.0时,万座嗜酸两面菌的加入几乎没有促进黄铜矿的溶解,这主要是由于高酸度严重抑制了万座嗜酸两面菌的生长。电解液中存在或不存在万座嗜酸两面菌时黄铜矿的阳极氧化电流都随着初始pH的增大而增大,同时在黄铜矿电极表面检测到了单质硫和铜蓝。结果表明,在化学浸出过程中黄铜矿是在质子作用和氧化作用下溶解的,黄铜矿氧化生成了铜蓝和单质硫。     

某难选金矿加温化学预氧化浸出技术

以某实际含铜金矿为研究对象,在氯盐酸性加温体系下,分析浸出温度、时间、矿物粒度、NaCl浓度、H2SO4浓度、氧气流量等因素对化学预氧化浸出除铜和浸出渣氰化浸金的影响过程.结果表明:在90%矿样粒度小于37 μm、浸出温度95 ℃、初始H2SO4浓度0.75 mol/L、起始NaCl浓度0.7 mol/L、液固比5-1、浸出时间24 h、搅拌速度750 r/min的条件下,可使铜的浸出去除率达到80%以上,预氧化渣金的氰化浸出率达98.23%.     

原电池效应对混合硫化矿细菌浸出的影响

研究了黄铜矿与黄铁矿混合矿细菌浸出过程的原电池效应，提出了原电池效应模型。研究结果表明：当黄铜矿细菌浸出过程中加入黄铁矿及C时，浸出率大大提高，黄铜矿浸出30d，Cu浸出率可达40％；单一黄铁矿细菌浸出时，黄铁矿会被大量氧化分解，而当与黄铜矿混合浸出时，黄铜矿氧化加快，黄铁矿氧化速率降低；加入C及黄铁矿与黄铜矿混合时，由于接触电位的影响，黄铜矿氧化反应电流增大、反应起始电位负移，反应加尉，而黄铁矿的氧化反应受到抑制；混合矿浸出过程中，黄铜矿表面Cu含量较单一矿浸出时低得多，说明混合效应对浸出具有强化作用；黄铜矿中Cu浸出愈多，表面生成的元素硫愈多，黄铁矿细菌浸出时，表面不会有元素硫产生。     

硫化锌精矿常压富氧直接浸出行为

借助工艺矿物学分析对常压富氧直接浸出条件下锌精矿中主要硫化物的浸出行为进行研究。结果表明,除黄铁矿外,其他硫化矿均会明显溶解。基于对浸出渣中单质硫与反应残余硫化物之间关系的分析,认为闪锌矿、黄铜矿、铜蓝、方铅矿的溶出可能遵循间接氧化方式,即硫化物首先酸溶,生成的H2S脱离矿物表面并迁移至溶液本体中进而氧化成单质硫。上述硫化矿的浸出过程可能受界面化学反应控制。对于磁黄铁矿的溶出,直接电化学氧化可能起主导作用,其浸出过程可能受产物层单质硫的扩散控制。     

细菌氧化预处理含砷难处理金矿的研究进展

含砷难处理硫化矿经过细菌预氧化,将包裹Au的硫化矿物毒砂、黄铁矿等溶解、破坏,将Au暴露出来,可大大提高后续氰化浸出中Au的回收率。细菌氧化技术具有投入低、工艺简单、污染轻或无污染等优点。作者在回顾细菌浸矿发展历史与现状的基础上,着重阐述了含砷难处理金矿细菌氧化预处理的机理、氧化菌种和工艺流程,并提出了该技术现存的一些亟待解决的问题。     

黄铜矿与斑铜矿在酸性细菌培养基中的电化学溶解对比(英文)

采用电化学测试和X射线光电子能谱(XPS)测试分析黄铜矿与斑铜矿在酸性细菌培养基中的电化学溶解过程。斑铜矿直接氧化反应比还原反应更容易发生,但黄铜矿既难被氧化,又难被还原。斑铜矿具有更高的氧化速率,从而比黄铜矿更容易被溶解。铜蓝(CuS)是黄铜矿与斑铜矿溶解过程的中间产物。因此,斑铜矿的溶解途径主要为直接氧化过程,中间产物铜蓝(CuS)可能限制其进一步溶解。黄铜矿的溶解途径包含了还原-氧化过程,其中,黄铜矿首先被还原为与斑铜矿类似的中间产物,再进一步被氧化,并产生铜蓝(CuS),而黄铜矿的最初还原过程是其溶解过程的主要限制步骤。     

利用生物质从黄铜矿和辉铜矿混合矿中可持续提取铜（英文）

本文阐述提铜工艺的可持续性。实际上,针对混合硫化矿(黄铜矿和辉铜矿),尝试在33.3℃下使用中温混合菌群的提铜工艺和三价铁浸出过程。其中,生物浸出实验是在矿石粒径-75+53μm范围内完成的。采用细菌作为催化剂,铜收率达65.50%。另一方面,在三价铁浸出过程中,矿石粒径为-53+38μm,温度升高至70℃时,铜收率提高到78.52%。与高温浸出过程相比,中温生物浸出过程在铜的提取中显示出明显的优势。通过SEM-EDS、FTIR和XRD表征,结合各种热力学分析,可以认为间接机理是主要的浸出机理。对于黄铜矿-辉铜矿混合矿而言,浸出机理分为三种过渡产物机理,即多硫化物机理、硫代硫酸盐机理和元素硫机理。铜形态转变为Cu_2S-Cu S-Cu_5Fe S_4-Cu_2S,最后转变为Cu SO_4。在发生亚铁氧化和硫酸铁生成反应的同时,细菌消耗掉硫化矿物,形成强酸,最后在低温下形成Cu SO_4,这种铜生产方案要求室温下氧化还原电位高于550m V,以便有效地提取铜。     

硫脲浸出银时其他矿物之行为

研究硫脲浸出硫化矿时共存矿物FeS_2、Sb_2S_3、CuFeS_2、FeAsS的浸出行为.并考查硫脲浓度、Fe~(3+)浓度、硫酸浓度及温度对银和杂质浸出的影响.银的最宜浸出条件是25℃、〔THIO〕=0.1mol/L、〔H_2SO_4〕=0.06mol/L、〔Fe~(3+)〕=0.04mol/L时经2h浸出,浸出率90%以上.当〔THIO〕≤0.3mol/L时,银的浸出反应是〔THIO〕的0.24级反应,〔Fe~(3+)〕≥0.12mol/L时,银的浸出反应是〔Fe~(3+)〕的0.27级反应.酸性硫脲溶液浸出银选择性良好,杂质铁、锑、砷、铜等因氧化反应而少量浸出,共存矿物氧化反应难易的顺序为:CuFeS_2>Sb_2S_3>FeAsS>FeS_2.黄铜矿因表面风化部分铜呈可溶状态存在,加上易被Fe~(3+)氧化,因此铜的浸出率较高.     

氯化物介质矿浆电解法浸出硫化铜精矿

研究了在ＦｅＣｌ３ＨＣｌＮａＣｌ体系中直接电解浸出硫化铜精矿矿浆制取铜粉的工艺条件及机理。试验表明，在阳极初始溶液含Ｆｅ３＋６０ｇ／Ｌ、ＨＣｌ３０ｇ／Ｌ、ＮａＣｌ１５０ｇ／Ｌ，阴阳极电流密度分别为３５０和６００Ａ／ｍ２，１００℃的条件下浸出５ｈ，可获得铜浸出率９８．８％、渣含铜０．３４％、铜粉纯度９７．５％的结果；Ｆｅ３＋浓度是影响铜浸出率最显著的因素，阳极上发生的主要反应是Ｆｅ２＋的氧化；元素硫产生的机理是酸直接分解黄铜矿生成Ｈ２Ｓ，Ｈ２Ｓ溶解后再被Ｆｅ３＋氧化。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。