某微细粒难选金矿氰化尾矿的浮选提金工艺试验研究

新疆某金矿历年来生产的氰化浸出尾矿,组成较为复杂,金、银、硫集中分布在-0.045 mm粒级中,通过对该金矿氰渣的实验室试验和扩大连续浮选试验研究,取得了金精矿品位19.50 g/t,回收率66.50%的工艺指标,有效地回收了该矿石中的微细粒金和包裹金。     

低品位微细粒金矿浮选精矿的处理工艺研究

针对低品位微细粒金矿中金的赋存特点,对其浮选精矿进行高压氧化-氰化浸出工艺处理。重点考察了高压氧化预处理过程中的温度、液固比和氧化时间对预处理效果的影响。预处理渣再磨后氰化浸出,金的浸出率(对浮选精矿)为94.30%,渣率为10.88%。     

提高金矿浮选回收率的选矿试验研究与生产实践

新疆阿希金矿由于原矿性质发生变化,浮选指标波动大。为了降低浮选尾矿品位,提高金浮选回收率,进行选矿试验研究。试验获得了浮选金精矿品位>40 g/t,浮选尾矿品位<0.7 g/t,回收率>85%的良好浮选指标。     

低品位石煤矿中钒和碳的浮选回收（英文）

在工艺矿物学的基础上,进行高碳含钒石煤浮选工艺研究。浮选工艺包括选碳流程和选钒流程,可以分别对碳和钒矿物进行富集。在碳浮选流程中,通过再磨工艺可以将碳和钒矿物有效分离。结果发现,浮选精矿中,钒的品位和回收率分别为1.32%和88.38%,尾矿产率为38.36%。碳精矿品位为30.08%,回收率为75.10%,可以直接作为燃料使用。对浮选产品进行酸法浸出实验,浮选产品的浸出率都在85%以上,说明该浮选工艺对浸出影响比较小。该浮选工艺可以减小钒浸出的处理量,降低冶炼成本,对石煤浮选工艺有借鉴作用。     

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%。     

含砷难处理金精矿提金新工艺

对某金矿合砷难处理金精矿进行了超细磨氰化提金工艺和焙烧氰化提金工艺的试验研究,获得金浸出率分别为96.77％和96．38％的良好指标。对比分析表明,超细磨氰化提金工艺无环境污染、工艺简单、低成本、金浸出率高,具有广阔的发展前景。     

金宝山铂族矿物氧压浸出-浮选联合工艺（英文）

为了生产适合冶炼的铂族精矿,提出一种氧压浸出-浮选联合工艺处理金宝山铂族矿物。结果表明:氧压浸出条件(矿物粒度、搅拌速度、液固比以及木质素磺酸钙用量)对浸出过程中贱金属(铜、铁和镍)浸出率以及浮选工艺中铂族金属(铂和钯)的回收率产生明显影响。浸出过程中贱金属硫化矿物的完全溶解导致铂族金属浮选降低了浮选载体的数量,降低浮选过程中铂族金属回收率。综合考虑贱金属浸出率和铂族金属回收率,确立如下最佳工艺条件:精矿粒度-0.043 mm占有率为73%,搅拌速度为400 r/min,液固比为10 mL/g,木质磺酸钙用量为0.6 g。最佳工艺条件下,铜、镍和铁的浸出率分别为87.6%、87.6%和90.3%。采用浮选工艺处理浸出渣获得浮选精矿铂族金属品位为420 g/t。     

某低品位铜硫矿综合回收浮选工艺技术试验研究

针对该低品位铜硫矿的矿物特征,采用抑硫浮铜的优先浮选方案,配合石灰、硫化钠组合抑制剂抑制黄铁矿,成功实现了铜硫的有效分离。该浮选工艺流程结构简单,最终取得了铜精矿品位20.02%,回收率94.33%;硫精矿品位47.33%,回收率79.24%较为理想的试验指标。     

贵州某黄金选矿厂弱酸性浮选工业试验

贵州某金矿含金4.3 g/t,金主要赋存在黄铁矿中,矿石含碳较高,属难选难冶型金矿。为实现该金矿资源的高效利用,采用热压预氧化打开矿石中金包裹,提高金的浸出率,同时将原有的碱性浮选工艺调整为弱酸性浮选。采用"二粗二精四扫"的选矿流程,进行工业试验。通过条件试验确定磨矿细度及各作业的药剂用量,最终获得金精矿金品位19.34 g/t,回收率88.25%。与原工艺相比,弱酸性浮选可以利用废酸,节约碱性调节剂的使用。     

高铁富金铜硫多金属矿选矿实验研究

某高铁富金铜硫多金属矿铁品位为31.81%,金品位为1.37 g/t,铜品位为0.70%,硫品位为6.52%,矿石中71.83%的金赋存于铜矿物、黄铁矿、磁铁矿等矿物,而铜矿物、黄铁矿、磁铁矿的嵌布粒度均较粗,普遍在+0.04 mm。采用“优先浮选铜-活化浮选硫-硫尾磁选回收铁”联合工艺处理该矿石,并采用ZA作铜捕收剂,全流程实验获得金品位27.80 g/t,铜品位20.60%,金回收率59.05%,铜回收率83.29%的铜精矿;金品位2.16 g/t,硫品位45.07%,金回收率20.24%,硫回收率86.25%的硫精矿;金品位0.80 g/t,铁品位60.83%,金回收率14.25%,铁回收率45.90%的铁精矿。实现了矿石中金铜铁及载体矿物的高效回收。     

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.     

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.