铀钼矿硫酸焙烧提取铀钼

采用硫酸焙烧-水浸法强化过程高效提取铀钼矿中的铀钼,运用单因素试验考察焙烧过程参数对铀钼浸出率的影响。结果表明:硫酸焙烧过程推荐参数为酸矿质量比0.5:1、硫酸浓度82%、焙烧温度270℃、焙烧时间120 min。优化条件下验证实验所得焙烧熟料水浸后铀钼浸出率可达92%～93%和81%～84%,较现有低温直接酸浸过程铀浸出率(85%～90%)有一定提高,钼浸出率(45%～50%)有大幅提高。对原矿、焙烧熟料、浸出渣物相进行XRD分析后发现,铀钼矿经过硫酸焙烧和水浸后主要组分已由原矿中铝硅酸盐和SiO_2转变为浸出渣中SiO_2。     

微细浸染型金矿的微波焙烧预处理研究

研究了微波焙烧预处理对微细浸染型难处理金矿浸出的影响。正交试验表明,各因素对浸出率影响程度大小依次为:微波焙烧温度、焙烧时间、浸出时间、浸出剂TY-3用量和氢氧化钠用量。在微波焙烧温度550℃,焙烧时间40 min,浸出剂TY-3用量14 kg/t,氢氧化钠用量8 kg/t,浸出10 h的优化条件下,浸出率达94.8%。XRD分析结果表明,经微波加热焙烧后,原矿中黄铁矿转化为赤铁矿。与马弗炉焙烧对比,微波焙烧可能具有选择性加热作用,更有利于矿石中包裹金的暴露。     

循环流态化焙烧加压浸出从极难浸石煤中提取钒

以广西某极难浸石煤钒矿为研究对象,研究循环流态化焙烧试样在加压浸出条件下的钒浸出率。结果表明:在相同酸浸条件下,循环流态化空白焙烧试样的钒浸出率高于钠化焙烧的钒浸出率。系统的焙烧浸出工艺对比研究表明:该石煤钒矿只有在循环流态化焙烧并加压高浓度酸浸作用下才能获得最高的钒浸出率,应属于极难浸石煤钒矿。在V(H2SO4):V(HF)=1:1和MnO2添加量(质量分数)为3%的条件下,循环流态化空白焙烧矿的最佳酸浸条件为液固比1:1、浸出温度150℃、浸出时间6 h,钒浸出率可达98.11%。同时,研究循环流态化空白焙烧矿加压浸出的动力学模型、浸出控制步骤及表观活化能。循环流态化空白焙烧能避免钠化焙烧产生的Cl2及HCl等有害气体的排放问题。从焙烧反应设备的创新应用着手,探索试验工艺条件,为极难浸石煤钒矿的工业化利用提供参考和依据。     

铜镍氧硫混合矿焙烧-浸出过程铜、镍、铁的转化

随着硫化镍矿资源的日趋枯竭,铜镍氧硫混合矿的利用将会愈发受到关注。通过对原矿进行差热-热重、XRD以及热力学分析,揭示焙烧过程矿石矿相的转变历程,研究铜镍氧硫混合矿焙烧过程中矿物粒度、焙烧温度和焙烧时间对铜、镍、铁转化的影响,探索浸出过程中溶剂、液固比、浸出温度及浸出时间对铜、镍、铁浸出的影响。结果表明:矿物粒度为74~80μm、焙烧温度为600℃、焙烧时间为2 h、选择水作为浸出溶剂、浸出温度为60℃、液固比为6:1、浸出时间2 h时,镍和铜的浸出率达到最高分别为46.25%和96.27%,铁的浸出率低于1%。     

响应面优化蔗渣焙烧还原低品位软锰矿的工艺(英文)

采用基于统计的优化策略优化了无氧条件下蔗渣焙烧还原低品位软锰矿的工艺。用中心组合设计收集实验数据,用二次模型表示锰浸出率与渣矿比(蔗渣与锰矿质量比)、焙烧温度、焙烧时间的函数关系,用统计分析(ANOVA)研究变量及变量的相互作用对浸出过程的影响。结果表明,渣矿比和焙烧温度对浸出过程的影响比焙烧时间的大,渣矿比和焙烧温度的线性项、二次项及其交互作用影响显著,而焙烧时间的影响却较小。利用所得的二次模型可得最佳工艺参数:渣矿比0.9:10、焙烧温度450°C、焙烧时间30min。在优化条件下,锰浸出率的预测值为98.1%,实验值为98.2%.     

石煤微波空白焙烧-酸浸提钒工艺

通过微波空白焙烧-酸浸提钒与传统加热焙烧一酸浸提钒和直接酸浸提钒的对比实验,考察H2SO<,4>用量和浸出时间对石煤中钒浸出的影响.结果表明:石煤在700℃下微波焙烧60 min,H2804用量为矿样质量的22%,浸出温度为90℃时,V2O<,5>浸出率达到83.50%,比传统加热焙烧一酸浸提钒和直接酸浸的浸出率提高约30%.通过对焙烧熟料酸浸和直接酸浸时Al2O3浸出率的分析发现,V2O<,5>浸出率与Al2O3浸出率呈正相关性.结合矿物晶体构造与微波加热原理,探讨了微波焙烧改善酸浸提钒的机理,认为微波焙烧可破坏含钒云母的晶体结构,是提高V2O<,5>浸出率的主要原因.     

MACA体系中循环浸出低品位氧化锌矿制备电解锌

以云南兰坪低品位氧化锌矿及其循环浸出渣的浮选精矿为原料,常温常压下在MACA(金属氨络合物)体系中进行循环浸出。浸出液先净化除砷和锑、再两段锌粉逆流置换深度净化,两次净化后液电积制取电解锌。考察工艺中循环浸出率、净化率、物质平衡以及电解锌质量和电耗等技术经济指标。结果表明:先用MACA法处理原矿粉,再浮选硫化锌的选冶结合流程是合适的兰坪低品位氧化锌矿的处理方案,原矿锌的平均浸出率为70.48%,其氨可溶锌浸出率达到89.14%,浮选精矿锌的浸出率为79.75%,杂质元素的净化率达到95%,电解锌纯度达到99.98%,电流效率可达97.02%。     

黔北务正道地区铝土矿焙烧脱硫及溶出性能的提升

提出了一种新的工艺路线—"闪烁焙烧+精矿拜耳法",研究矿物物相变化和热分析,对焙烧脱硫过程中的重要参数(焙烧温度和焙烧时间)进行系统优化,全面提升焙烧精矿在拜耳法工艺中的溶出性能。结果表明:在活化焙烧温度为550℃、炉内停留时间为1.6 s的条件下,所得焙烧矿中硫化物型硫的平均质量分数约为0.05%,脱硫率达到95.2%,且后续溶出试验效果明显优于原矿的;在溶出温度270℃、溶出时间60 min、石灰添加量14%、苛性碱质量浓度245g/L且配料苛性碱与氧化铝的摩尔比为1.40的条件下,焙烧矿相对溶出率可达到95%以上,相比原矿的提高2%～3%。研究成果为加快推进高硫铝土矿的高效产业化利用提供了一种新工艺及相关基础数据。     

基于田口法的铜阳极泥微波浸出工艺

基于田口方法,提出微波浸出铜阳极泥的优化方法,并对铜、碲、硒的浸出率进行信噪比分析。结果表明,固液比对铜、碲、硒浸出率的贡献率最大,贡献率分别达到60.83%、54.76%和62.05%。固液比是铜阳极泥微波浸出过程最重要的工艺参数,时间对于铜、碲浸出率为较重要因素,酸浓度对于硒浸出率为较重要因素,微波功率对于铜、碲、硒浸出率的贡献率都较小,分别为4.23%、12.37%和10.32%。铜浸出最优条件如下:微波功率450 W、时间5 min、固液比0.10 g/mL、酸浓度1.0 mol/L;碲、硒浸出最优条件如下:微波功率700 W、时间9 min、固液比0.10 g/mL、酸浓度1.0 mol/L。在优化后的工艺条件下进行验证实验,铜浸出率达到99.88%以上,碲浸出率达到95.70%以上,硒浸出率达到38.22%以上。     

硝酸氧化浸出难冶炼高砷钴矿

在100g钴矿加入39mL浓硫酸、浸出温度80℃、浸出时间2h、液固比2:1时,采用常规的硫酸浸出,钴浸出率仅为16.86%;当100g钴矿中加入42.5mL浓硫酸、在焙烧温度630℃、焙烧时间1.5h的焙烧条件下,采用硫酸化焙烧后硫酸浸出,钴浸出率达到67.48%;在100g钴矿中加入39mL浓硫酸和56mL浓硝酸、浸出温度60℃、浸出时间4h、液固比为3:1时,采用硝酸氧化下硫酸浸出,钴浸出率为96.35%。     

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).     

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.     

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.     

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。