The extraction of vanadium and scandium from red mud were carried out by leaching with tita-nium dioxide wastewater.The effects of liquid to solid ratio, leaching temperature, leaching time and stirring rate on the leaching rate of vanadium and scandium were investigated.The phase composition of lea-ching residue and the chemical composition of leaching solution were analyzed by XRD and ICP-AES.The results show that under the conditions of liquid to solid ratio of 6 mL/g, stirring rate of 400 r/min, leaching temperature of 75 ℃ and leaching time of 1 h, the leaching rates of V and Sc are 75% and 80%,respectively.Compared with the titanium dioxide wastewater, the leaching solution contains significantly decreased H+ concentration, vanadium and scandium are enriched and the concentration of iron and aluminum is also increased.Compared with the red mud, anhydrite minerals appears in the leaching residue, while calcite is completely dissolved, cancrinite, brookite and hematite are partially dissolved.

The electrochemical reduction process of Y(Ⅲ) and the cathode behavior of Y₂O₃ in YF₃-LiF molten salt system were studied by cyclic voltammetry.The results indicate that the reduction potential of Y(Ⅲ) on molybdenum electrode is-0.95 V(vs.Pt) in YF3-LiF molten salt system, and the reaction is a quasi reversible reaction that transfers three electrons in one step.The redox peak does not change with the scanning speed, which indicates that the reaction is a quasi reversible reaction with great reversibility.The peak current Ip is linearly related to v^1/2,so the reaction is controlled by diffusion with diffusion coefficient of 3.626 4×10^-8 cm²/s.The addition of Y₂O₃ into molten salt contributes to reducing reduction potential of Y(Ⅲ) and has a certain depolarization effect.There are three different reduction current peaks in the reduction process of Y(Ⅲ) on the iron electrode.Yttrium-iron alloy phase is formed by underpotential deposition and yttrium metal is formed by electroreduction.

The solubility of yttrium oxalate in oxalic acid solution with different concentration(0.6~1.0 mol/L) was determined by FBRM combined with dynamic method at atmospheric pressure and 318.15~343.15 K.The experimental results show that the solubility of yttrium oxalate in oxalic acid solution with different concentration decreases with the increase of temperature and increases with the increase of oxalic acid concentration.Apelblat equation and polynomial empirical equation are used to fit and correlate the experimental data, and the correlation results are good.When the concentration of oxalic acid is low, the effects of the two models are similar.When the concentration of oxalic acid is high, Apelblat equation is slightly better than polynomial empirical equation.The solution enthalpy and entropy of yttrium oxalate in different oxalic acid solution calculated by Van′t Hoff equation are negative, the dissolution process is a non-spontaneous exothermic process, and the main driving force of this process is entropy driving.

Ferrosilicon alloy containing titanium was prepared by carbothermal reduction and induction melting with a polymetallic ore from Xinjiang as raw material.The effects of carbothermal reduction temperature, carbon content and holding time on metal recovery, alloy composition and slag phase were studied by single factor experiment.The experimental results show that under the optimum single factor conditions of 2 073 K carbothermal temperature, 0.8 times of theoretical carbon content and 0.5 h holding time, the highest metal recovery is 52%.The contents(mass fraction) of Al, Si, Fe, Ti and C in alloy are 0.338%,39.74%,45.54%,6.84% and 0.058%,respectively, and the main phase of reduced slag is MgAl₂O₄.

Zirconium is an indispensable material in nuclear industry due to its excellent nuclear properties.Hafnium co-exists with zirconium in nature, their physicochemical properties are extremely similar, but their nuclear properties are quite opposite.Therefore, the separation of zirconium and hafnium for nuclear grade zirconium production has been an important research topic in nuclear industry for a long time.At present, a variety of zirconium and hafnium separation technologies have been developed, which can be roughly divided into pyro-and hydro-metallurgical processes according to their characteristics.In this paper, the research progress on the main zirconium and hafnium separation technologies is reviewed, and the research and development of new nuclear grade zirconium production technologies are prospected.

The research progress on quality control of APT calcination, tungsten oxide reduction and W powder carbonization in the preparation process of high-quality ultrafine WC powder is reviewed.The qua-lity of APT raw material and the control of process parameters in the production process are the key to the preparation of ultrafine WC powder.APT with single property is beneficial to control the quality of calcined products, and optimizing calcination process parameters can avoid entrained hard particles.It is di-fficult to control consistent reaction conditions in the reduction process of tungsten oxide.When the heterogeneous reactions simultaneously occur, the key is to control the formation and reduction of WO2 and the growth of W powder.The uniformity of both composition and grain size of WC particles should be con-sidered in the carbonization process.

After vertical melting sintering, the axial density of large unit-weight doped tungsten rods is low at the two ends and high in the middle, which leads to cracks and splits on the end surface of tungsten rods after rotary forging.Therefore, the scheme of reducing the local diameter of both ends of doped tungsten rods was proposed, and the optimal diameter reduction amount was determined.When the diameter of the two ends of doped tungsten rods decreases by 1.2~1.8 mm, the end density of tungsten rods after vertical melting sintering increases, the difference of the overall density distribution decreases, and the grain size of the restricted area is almost the same as that of the non restricted area.At the same time, the surface cracks after rotary forging are reduced, and the comprehensive processability of tungsten rods is improved.

Low-temperature La/Ce doped Mn-based denitration catalyst powders were prepared by copre-cipitation.The sulfur resistance of the catalyst powders was improved by SO₄^2- acidification treatment.ICP,FT-IR,XRD,SEM,BET and denitration activity test were used to characterize the catalyst.The results show that when calcination temperature is 500 ℃ and 0.2 mol/L H2SO4 is employed for acidification treatment, the prepared La1-Ce6-Mn/Ti catalyst powder has the largest Mn/Ti mass ratio and the most active sites with specific surface area of 105.34 m2/g and denitration efficiency of 84% at 200 ℃.

Tensile strength, yield strength, elongation and reduction of area of the Nb-1 Zr alloy at 1 000~1 800 ℃ were tested, and the fracture morphology after unidirectional tensile test was observed.The results show that with the increase of temperature, the tensile strength and yield strength of Nb-1 Zr alloy at high temperature decrease from fast to slowly, and the two gradually approach.The elongation is almost unchanged at 1 000~1 200 ℃,but it increases rapidly with the increase of temperature above 1 200 ℃.The reduction of area does not change much within the test temperature range.The major deformation modes of Nb-1 Zr alloy are dislocation slipping at 1 000~1 200 ℃ and grain-boundary sliding at 1 400~1 800 ℃.There are two kinds of second-phase particles in Nb-1 Zr alloy: Zirconia particles mainly play the role of dispersion strengthening, while zirconium carbide particles mainly play the role of precipitation strengthening.

ZrCo-based alloy with excellent anti-disproportionation performance was developed by alloying, that is ZrTiCoMm alloy.Pd membrane was deposited on the ZrTiCoMm alloy by chemical plating.The characteristics of Pd membrane was analyzed by SEM,EDS and cross-section BSE imaging.The activation kinetic performance and P-C-T curve of Pd/ZrTiCoMm were tested, and the influence of Pd membrane on anti-poisoning performance of ZrTiCoMm alloy was studied.The results show that a dense and uniform Pd membrane with a thickness of about 3 μm can be deposited on the surface of ZrTiCoMm alloy particles.Pd/ZrTiCoMm alloy has excellent activation kinetic performance, and its saturated hydrogen absorption capacity at room temperature is over 200 mL/g.By fitting Van′t Hoff equation with P-C-T curve of hydrogen absorption and desorption process, the equilibrium pressure of hydrogen absorption is calculated, that is about 1 Pa at room temperature, and the equilibrium pressure of hydrogen desorption can reach 100 kPa only by heating to 520 K.The hydrogen absorption kinetic performance of ZrTiCoMm alloy without coating and coated with Pd membrane was tested in 4% N₂+1% O₂+90% H₂ mixed gas.It is found that uncoated ZrTiCoMm alloy almost loses its hydrogen absorption ability in the mixed gas.However, the hydrogen absorption capacity of Pd/ZrTiCoMm alloy decreases with the increase of hydrogen absorption and desorption times, but the hydrogen absorption capacity in the initial seven times can still reach more than 55% of that in high purity hydrogen, and the hydrogen absorption kinetic performance is also excellent.