The theoretical breakthrough of the mainstream technology in hydrometallurgy of tungsten and its existing problems in engineering and technology are summarized.The factors of China's tungsten re sources, technology and environmental protection policies are also comprehensively analyzed. A new tung sten metallurgy technology, sulfuric-phosphoric mixed acid decomposition technology of scheelite, developed by Central South University is introduced. The new technology can solve these problems in the cur rent tungsten hydrometallurgy. It provides a new way for promoting the healthy development of tungsten industry in China under the new situation.

The nanofiltration process has been widely used in the metallurgical process of rare metal tung sten, molybdenum and rare light metal lithium. Because of expansion and deepening of the research on nanofiltration process,it is necessary to establish a model which can accurately predict the performance of nanofiltration membrane. Many nanofiltration process models are formed and several nanofiltration mathe matical models described in this study are as follows: the simple irreversible thermodynamics model and the solution-diffusion model, the steric hindrance-pore model concerning nanopore, the charge model, the electrostatic and steric-hindrance model and the Donnan-steric partitioning pore model introducing charge factors,and the steric, electric and dielectric exclusion model with dielectric effect. Then the differences among the models and their application ranges are respectively discussed. The study of finite element analy sis and artificial neural network in the simulation of nanofiltration process is reviewed,and research priori ties and directions are put forward.

Using waste lithium titanate from anode materials of Li-ion batteries as the raw material and after pretreatment,Li and Ti in waste materials were separated and recovered by dilute sulfuric acid preferential leaching process. The effects were investigated of sulfuric acid concentration, liquid-solid ratio, leaching temperature and leaching time on the leaching rate of lithium and titanium in the acid leaching process. The experimental results show that the optimized dilute sulfuric acid preferential leaching process parameters are as follows: sulfuric acid concentration is 4 mol/L,liquid-solid ratio is 6:1 , leaching temperature is 80℃ and leaching time is 4 h. Under these conditions, the primary leaching rate of lithium can reach 90%,and that of titanium is 1.08%.

The production process of manganese monoxide roasted product prepared by using manganese di oxide ore as raw material,and using single cylinder dryer for drying ore,high pressure grinding roller for milling and electrothermal rotary kiln for reduction roasting was introduced. The reduction rate of manga nese can reach 98.5%,and high quality raw materials can be provided for the subsequent leaching,purifica tion, electrolysis, reprocessing, evaporation crystallization and other process steps to produce electrolytic manganese dioxide and high purity manganese sulfate products.

Arsenic (As) is a common impurity element in scheelite,and needs to be removed in the metallurgical process. However, the effect of arsenic on the subsequent tungsten products is not clear. APT-As composite powders with As mass content of 1% was prepared by using ammonium tungstate and As element as raw materials. After the treatment of calcination and carbonization, violet tungsten oxide(W18O49-As) and tungsten carbide (WC-As) containing arsenic were obtained, respectively.X-ray diffractometer, scanning electron microscope, high-resolution transmission electron microscope and differential scanning calorimeter were used to analyse the morphology and structure of W18O49-As and WC-As. The results show that As element mainly exists in the surface of the bar W18O49-As in the form of W2O3 (AsO4)2 phase,making bar W18O49-As easily break. The initial reaction temperatures of reduction and carbonization of W18O49-As are lower than those of W18O49. The phase of W2O3 (AsO4)2 is distributed between W18O49 powders,hindering substance migration and diffusion in the process of W18O49 carbonization and inhibiting aggregation and growth of fine WC particles,so the uniform WC-As powders are obtained.

The process of doping yttrium by co-precipitation with yttrium nitrate aqueous solution added during evaporation crystallization of ammonium tungstate was studied. Yttrium-doped ammonium paratungstate powder was prepared by the above process,and then tungsten carbide powder containing yttrium was prepared by redox,carbon distribution and carbonization.The results show that yttrium in APT pow der prepared by co-precipitation has relatively uniform distribution, and exists mainly in the form of Y(OH)3. The average particle sizes of tungsten carbide powders doped with 0.5%Y and 1%Y is 0.37μm and 0. 28μm,respectively.Yttrium doping has the effect of refining tungsten carbide powder.

The material used in nuclear spent fuel reprocessing equipment and three-phase corrosion test ap paratus are introduced. The latest research progress on corrosion resistance of Ti-Ta and Ti-Ta-Nb typical corrosion resistant alloys in the simulated environment of nuclear spent fuel reprocessing is reviewed.

The universal testing machine was used to carry out different strain compression tests of the isostatic-pressure beryllium at room temperature.SEM and EBSD were used to analysis twinning formation and texture evolution in beryllium material. The results show that only stretching twinning {1012} of be ryllium forms during room temperature compression. During the evolution of stretched twinning,twinning formation and growth has great promotion effect on the large-angle changing of grains and the formation of new texture {0001}. However,the coordination effect is reduced on the slip deformation of beryllium dur ing the later twinning period. In addition, uniaxial compression couples also play an important role in the formation of new texture {0001}.

The interface has a significant regulatory effect on the electroacoustic transport properties of the material.Therefore,the effect of homogeneous interface density on thermoelectric performance of P-type Bi0.5 Sb1.5Te3 alloy was investigated. The results show that the electrical conductivity of the alloy decreases and Seebeck coefficient increases with the increase of homogeneous interface density. Meanwhile,the ther mal conductivity decreases attributed to the enhanced scattering of phonons by increasing homogeneous in terface density. Because the sintered sample prepared by pulverizing for 1 min has the optimal electrical properties,it has excellent thermoelectric performance in the high temperature range.

Superalloy with difficult machining problem is the key material for engines. In order to reduce the tool wear depth in the machining area,the EHM simulation model of the superalloy Inconel 718 is estab lished by DEFORM-3D software. Then the simulation experiments of single factor experiments and or thogonal experiments are carried out with the EHM simulation model. The experimental results show that with the continuous increase of cutting speed, cutting depth and feed rate, the tool wear depth shows a steadily upward tendency,and the increase of the initial temperature of the workpiece continuously reduces the tool wear depth. Under the condition that the initial temperature of the workpiece keeps rising, the wear depth of the EHM simulation model tool is reduced by 21.9% compared with that of non-current heating cutting tool.