山东某含金磁黄铁矿浮选尾矿磁选回收试验研究

山东某含金磁黄铁矿原矿金品位1.60 g/t,硫品位1.86%,属含金硫铁矿。矿石性质研究结果表明,部分以磁黄铁矿为载体的金,矿物含量为0.96%,金品位8.25 g/t,原矿金分配率5.25%。生产流程对以磁黄铁矿为载体的金矿物的回收水平仍有提高空间。为了解决这一问题,开展了从生产原矿和生产尾矿中回收以磁黄铁矿为载体的金的对比试验,结果表明,磁选不宜用于原矿、重选不宜用于尾矿中载金磁黄铁矿的回收;尾矿磁选流程可以实现含金磁黄铁矿的有效富集,最终选择全粒级磁选工艺流程,获得了金品位1.52 g/t,硫品位2.87%的含金磁黄铁矿。尾矿金、硫回收率分别为52.09%、62.93%,对原矿回收率分别为12.27%、18.56%,实现了以磁黄铁矿为载体的金矿物的综合利用。     

某含银高硫铜矿的综合回收试验

某含银高硫铜矿含铜0.76%、硫24.35%及银34.92 g/t,有价矿物种类多、矿石性质复杂,采用抑硫优先浮选铜-活化浮选硫的原则工艺流程进行试验,配合石灰作为硫化铁矿物抑制剂以及筛选出丁基黄药+酯-105作为硫化铜矿物的组合捕收剂,强化了银在铜精矿中的富集。在选定工艺条件下,可获得铜品位21.60%、银品位602.84 g/t的铜精矿(铜和银回收率分别为89.30%和54.39%),硫品位45.60%、银21.55 g/t的硫精矿(硫和银回收率分别为89.79%和29.59%),实现了铜、硫和银的综合回收利用。     

云南某铜尾矿中铜和金的选矿回收试验

云南某铜尾矿主要金属矿物有黄铜矿、黄铁矿、磁黄铁矿等,黄铜矿以原生硫化铜为主,金以裸露金和黄铜矿包裹金为主。为综合回收其中有价铜、金,进行了选矿试验。试样在磨矿细度为-200目占85%的情况下采用两次粗选、第二次粗选后扫选、两次精选、第二次精选后扫选、混精矿再磨至-325目占85%、粗选后扫选精矿再磨至-325目占85%、中矿循序返回流程处理。最终获得铜品位15.51%、回收率68.34%、产率1.41%的铜金精矿,其中的金品位19.93 g/t、回收率54.04%,银品位231.72 g/t、回收率41.89%。     

国外某铅、锑复杂矿石中金的提取预富集试验研究

国外某铅、锑复杂矿石中主要金属矿物为脆硫锑铅矿及黄铁矿,矿石中的伴生金主要赋存于脆硫锑铅矿中,其次赋存于黄铁矿中。矿石锑品位1.50%,铅品位2.21%,金品位5.1 g/t,对矿石进行选矿提取预富集,有效地回收矿石中各有价金属。此外,对选矿预富集所得的产品的冶炼加工技术进行了探讨。     

河北某石英脉型金矿石选矿试验研究

河北某石英脉型金矿石金品位5.4 g/t,银品位6.4 g/t。针对该矿石性质,开展浮选试验,在最佳药剂制度条件下浮选闭路试验获得精矿金回收率为78.9%,银回收率35.6%,金品位44.0 g/t,银品位23.5 g/t。为提高选矿指标,开展重选与浮选工艺联合试验。与单一浮选工艺相比,重、浮联合工艺获得混合精矿金回收率提高6.8%,银回收率提高2.2%。     

某高硫微细粒金矿选冶试验研究

某高硫金矿中金矿物与黄铁矿紧密共生，金矿物和黄铁矿平均粒径分别为3.58和32.80μm，嵌布粒度较细，在实际生产中精矿品位和回收率均不理想。为进一步提高精矿品位和回收率，针对该矿特点，确定黄铁矿为浮选目标矿物，通过系统条件试验和精选试验得到了最优浮选工艺流程和参数，继而开展开路试验和闭路试验，得到的浮选指标并不理想。基于中矿中黄铁矿多是连生体的判断，对浮选中矿进行再磨处理，获得了精矿金品位17.4 g/t、金回收率80.66%的满意指标。同时，结合“超细磨”、“碱浸预处理”工艺，对浮选精矿进行浸出试验，得到金浸出率77%的满意指标，为生产现场提供了具有指导意义的技术方案。     

山东某含金硫铁矿强化浮选回收试验研究

山东某含金硫铁矿原矿金品位为3.06 g/t、含硫量为2.65%。工艺矿物学研究表明,金主要以自然金等独立金矿物形式存在,其次以黄铁矿为载体,少量以磁黄铁矿为载体。采用快速浮选和常规浮选组合的工艺流程,以硫酸铜做活化剂,MA-1做捕收剂,HX-609做起泡剂,分别获得了金品位为34 g/t、32 g/t的快速浮选精矿和常规浮选精矿,金总回收率达到90%以上。     

紫金山铜金矿中金铜银的赋存状态研究

采用矿物自动分析仪(MLA)、扫描电镜(SEM)、X射线衍射(XRD)研究了紫金山金铜矿入选矿石中有价元素铜、金、银的赋存状态以及分选过程中的金属走向。结果表明,铜矿物主要有蓝辉铜矿、铜蓝、硫砷铜矿,金银以游离矿物和硫化物包裹体为主。铜矿物常见沿明矾石溶蚀孔洞或碎裂缝隙充填,与黄铁矿密切连生,从原矿中分选铜矿物,理论品位为Cu 69.70%,理论回收率93.55%。中粒金嵌布于铜矿物和黄铁矿矿物粒间或裂隙,可随着铜和硫的回收进入铜、硫精矿,金的理论回收率分别为57.19%和27.27%;微细金粒包裹于明矾石和石英中,随脉石损失于尾矿中。银以显微银为主,多见呈微细粒包裹于硫化矿物中,铜精矿和硫精矿中银的理论回收率分别为56.96%和26.71%。     

富银铜锌多金属矿选矿试验研究

某富银铜锌多金属硫化矿,其银品位为125 g/t,铜品位为0.26%,锌品位为1.13%,硫品位为3.04%;90%的银赋存于银黝铜矿、黝铜矿等铜矿物中。采用“优先浮银铜﹣锌硫混浮﹣锌硫分离”工艺流程进行处理,选择高效银捕收剂SAC强化银的回收,全流程实验获得的银(铜)精矿含银10094 g/t,含铜16.67%,银回收率88.78%,铜回收率80.23%,锌精矿含锌45.46%,锌回收率81.81%。实现了矿石中银铜锌的综合回收。     

云南某含银铜矿伴生银矿物强化回收实验研究

云南某含银铜矿石银品位为21.77 g/t,主要赋存于黄铜矿、游离银和磁黄铁矿中,在选别过程中铜硫分离时兼顾银的回收具有一定的难度。采用抑硫浮铜流程,研究筛选出石灰及Z200作为合适的调整剂和高效捕收剂,在抑制黄铁矿、磁黄铁矿的同时强化银的回收。最终闭路试验获得了品位23.92%、回收率97.10%的铜精矿,且含银136.38 g/t,银的回收率达到77.05%,实现了铜硫分离的同时强化银的回收。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.