赤泥酸浸的试验研究

以HCl和H2SO4为浸出剂,对赤泥中各有价金属的浸出条件进行了较系统的试验研究。结果表明,先采取低浓度HCl浸出,残渣再用高浓度H2SO4分解的两段浸出方式为佳。一段浸取盐酸浓度为6mol／L．液固比L／S=4：1．反应温度50℃,反应时间1h。Sc2O3的浸出率大于80％,TiO2的浸出率为1％左右。二段浸取硫酸浓度为92％．酸渣比为3：1．熟化温度为200℃,熟化时间为1．5h。TiO2的浸出率为96．57％。     

复杂金精矿铁锍酸溶渣控电位氯化浸出富集贵金属金

以复杂难处理金精矿火法造锍捕金所得铁锍合金的硫酸浸出渣为原料,采用控电位氯化浸出工艺分离酸溶渣中的Cu、As、Sb等主要杂质元素,贵金属Au单向富集得到高品位金泥,Au泥经过硫酸化焙烧脱硫进一步富集贵金属金。结果表明:双电极体系控电位氯化浸出优化条件为[H⁺]5mol/L、浸出电位380m V、液固质量比5:1、温度85℃和搅拌浸出2 h,所得渣率为28.2%,浸出渣中Cu、As、Sb含量分别降到0.18%、0.095%、0.084%,浸出率分别达到99.6%、99.8%、99.8%,浸出渣主要成分Si和S的含量分别为29.39%和22.72%,Au品位富集到2.609%;浸出渣硫酸化焙烧脱硫的烧成率为66.5%,S含量降至0.87%,脱硫率为96.2%,焙砂的主要物相为SiO₂和单质金,Au品位富集到3.937%。复杂金精矿铁锍合金酸溶渣通过控电位氯化浸出除杂—焙烧脱硫可将贵金属金有效富集。     

以废茶叶为还原剂在硫酸溶液中还原浸出氧化锰矿（英文）

采用废茶叶在硫酸溶液中还原浸出加蓬和湘西氧化锰矿石,探索废茶叶用量、硫酸浓度、固液比、浸出温度和反应时间对浸出过程的影响。对加蓬氧化锰矿,优化的浸出条件为:氧化锰矿与废茶叶的质量比10:4、硫酸浓度2.5 mol/L、固液比7.5:1、浸出温度368 K、浸出时间8 h;在此条件下,加蓬氧化锰矿的浸出率几乎达100%。对于湘西氧化锰矿,优化浸出条件为:氧化锰矿与废茶叶的质量比10:1、硫酸浓度1.7 mol/L、液固比7.5:1、温度368 K、浸出时间8 h;在此条件下,锰的浸出率达到99.8%。氧化锰矿的还原浸出过程符合内扩散控制模型,加蓬和湘西氧化锰矿石的还原浸出反应表观活化能分别为38.2 kJ/mol和20.4 kJ/mol。采用X-射线衍射(XRD)和扫描电子显微镜(SEM)对浸出前、后的锰渣进行表征。     

铁矾渣热酸分解及硫脲提银

进行铁矾渣热硫酸分解和分解渣硫脲法提银的试验研究,考察硫酸用量、分解温度、反应时间、液固比对铁矾渣中Fe、Zn、Ag浸出率的影响,以及硫脲法提银的最优条件。结果表明:在硫酸用量为其理论值的1.5倍、分解温度95℃、时间2.5 h、液固比2.5:1的最佳条件下,铁矾渣中Fe和Zn浸出率分别为93.85%和92.25%,而Ag的浸出率仅为1.99%。分解液净化后可用中温水热法制备铁红,分解渣中Ag富集到1060 g/t。在液固比10:1、硫脲浓度15 g/L、浸出温度90℃、反应时间2.5 h的最优条件下,Ag的平均浸出率在93%以上,同时,渣中Pb的品位由1.7%提高到7.5%。     

铜冶炼烟尘的控电位氧化浸出（英文）

采用氧化浸出和电位控制技术从铜冶炼烟尘中浸出金属,研究H2O2用量、H2O2加入速度、初始盐酸浓度、浸出温度、初始液固比和浸出时间对金属浸出率的影响。最终得到最优浸出条件为:H2O2用量0.8mL/g(氧化还原电位为429 mV)、H2O2加入速度1.0 mL/min、初始硫酸浓度1.0 mol/L、初始盐酸浓度1.0 mol/L、浸出温度80°C、初始液固比5:1 mL/g以及浸出时间1.5 h。在此最优条件下,铜冶炼烟尘中的铜和砷能被有效地浸出,剩下的浸出渣可作为一种合适的铅冶炼资源。此时,铜、砷和铁的平均浸出率分别为95.27%、96.82%和46.65%。     

锌冶炼中浸渣锌还原浸出机制与动力学

以锌冶炼中浸渣为研究对象,研究中浸渣的化学成分及锌的存在形态,锌主要以铁酸锌形式存在。采用SO2做还原剂,研究温度、初始硫酸浓度、二氧化硫分压对锌浸出效率的影响,并分析中浸渣中锌还原浸出反应机制及动力学。结果表明:H+在锌还原浸出过程中起关键作用,锌还原浸出反应活化能为31.67 k J/mol,为化学反应控制;SO2做还原剂时,反应时间、液固比及初始酸度均大幅降低。反应最佳工艺条件:初始硫酸浓度80 g/L、温度95℃、液固比(L/S)10 m L/g、二氧化硫分压200 k Pa、反应时间120 min。该工艺条件下,中浸渣中锌浸出率达99%以上。XRD和ICP分析表明:中浸渣中铁酸锌分解,硫化锌在该反应条件下未完全浸出,还原浸出渣中主要化学成分为铅和锌,主要物相为Pb SO4和Zn S。     

低品位铂钯精矿的富氧压浸出

对高镁低品位复杂铂钯精矿进行工艺矿物学分析,提出采用硫酸氧压浸出工艺对该精矿中的贱金属铜、镍、铁选择性浸出分离并富集铂钯的处理工艺。考察磨矿粒度、反应温度、时间、初始硫酸浓度、氧压、搅拌速度、木质素磺酸钙用量、液固比对铜、镍、铁浸出率及渣率的影响,确定最佳工艺参数。实验结果表明:当精矿粒度小于43μm占有率为93%、时间3 h、浸出温度150℃、初始硫酸浓度2 mol/L、氧分压0.7 MPa、搅拌速度400 r/min、添加剂木质素磺酸钙用量0.6 g、液固比5:1的最佳工艺条件下,铜浸出率达99.27%、镍浸出率达98.04%、渣率为37%左右,铂钯几乎不被浸出,铂和钯在浸出渣中富集近3倍。     

混合酸溶液浸出刚玉烟尘灰中的镓（英文）

为了从高硅含量的刚玉冶炼烟尘中提取镓,提出一种硫酸与氢氟酸混合酸溶液浸出的方法,并对浸出过程的各项实验参数进行优化。结果显示,当单独使用硫酸作为浸出剂时,刚玉烟尘中镓的浸出率仅为38%。从刚玉烟尘灰的微区成分分析结果中可知,烟尘中的富硅相镓含量较高;这部分镓无法溶入硫酸溶液。氢氟酸的加入对二氧化硅产生侵蚀,从而显著提高了刚玉烟尘灰中镓的浸出率。研究反应时间、温度、氢氟酸浓度和硫酸浓度对镓浸出率的影响。结果表明,在最佳浸出条件下,烟尘中镓的浸出率可达到91%。最佳的浸出参数如下:反应时间4 h、反应温度80°C、混合酸溶液中硫酸浓度1.5 mol/L、氢氟酸浓度6.4 mol/L和液固比5:1 (mL/g)。     

铵盐焙烧-酸浸法从石油重整废催化剂中富集回收铂的研究

采用铵盐焙烧-酸浸法进行了从石油重整废催化剂中富集回收铂的研究。结果表明,适宜的铵盐焙烧条件为:硫酸铵与废催化剂质量比为7.5,焙烧温度350℃,焙烧时间5 h;稀酸浸出条件:液固比12.5,浸出温度80℃,硫酸浓度为0.5 mol/L,浸出时间3 h。在上述条件下,铂的富集倍数达到274倍以上。通过XRD分析,焙烧产物的物相主要以硫酸铝铵形式存在,焙烧产物通过稀酸浸出,实现铂的富集回收。     

从赤泥高炉炼铁炉渣中回收钪

为了研究在硫酸介质中直接浸出拜耳法赤泥高炉炼铁炉渣中钪的工艺条件,通过正交试验,考察了硫酸浓度,反应温度和反应时间等因素对钪的浸出效果的影响,并通过单因素试验优化了工艺条件。结果表明,影响钪的浸出率的主要因素依次为反应温度,硫酸浓度和反应时间;钪浸出的最佳条件为:硫酸浓度7.36 mol L-1,反应温度80℃,反应时间1 h,在此条件下钪的浸出率能达到82.38%。     

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。