A new process for the extraction and recovery of tungsten from APT crystal mother liquor in N235/isooctanol system was proposed and studied.The effects of organic phase composition,feed pH,temperature and other factors on tungsten extraction were studied.The extraction and stripping isotherms were drawn.And the test of simulated multi-stage countercurrent extraction was conducted.The results show that high-fold enrichment and recovery of tungsten and efficient separation of SO₄^2-and Cl^-from the ammonium paratungstate crystal mother liquor can be achieved in the solvent extraction system of N235/isooctanol.When the acidified feed liquid with WO3content of 22.1g/L and pH value of 3.5is subjected to4-stage countercurrent extraction,1-stage washing and 2-stage stripping,and the organic phase consisting of 10%N235,20%isooctanol and sulfonated kerosene is used,the results are obtained as follows:WO₃content in the raffinate is less than 0.02g/L,WO3recovery rate is higher than 99.5%,WO₃content in the stripping solution is higher than 230g/L,and the removal rate of SO₄^2-or Cl^-is greater than 98.5%.

To solve the problem that calcium molybdate and low-valence molybdenum in industrial molybdenum oxide are insoluble in ammonia water and there are other impurity elements in the leaching solution,a new efficient and simple process was studied,mainly including the two parts of leaching and extraction.The effects of Na₂CO₃dosage,leaching temperature,leaching time and liquid-to-solid ratio on molybdenum leaching were investigated.The extraction and stripping conditions were explored by changing phase ratio,extraction time,extraction stage,stripping agent concentration and stripping stage.The results show that under the conditions of Na₂CO₃dosage coefficient 1.16,leaching temperature 140℃,leaching time 3 h,and liquid-solid ratio 4∶1,the molybdenum leaching effect is the best,and the leaching rate is over 99%.The optimum technological conditions of extraction and stripping are as follows:the extraction conditions are organic phase composition of 15%N235+10%octanol+75%kerosene,pH value of 3.2,extraction time of 6 min,phase ratio of 3.5∶1 and 4-stage countercurrent extraction;the stripping conditions are 13.64%NH3·H2O as the stripping agent,stripping time of 10 min,phase ratio of 5∶1 and 2-stage countercurrent stripping.Both the extraction rate and stripping rate of molybdenum are over 99%under the above conditions.This technology has high utilization efficiency and low loss of molybdenum resources,and the concentration of molybdenum solution can reach 173.45 g/L after purification.

The electrochemical deoxidation process of tantalum in molten LiCl-NaCl was studied by cyclic voltammetry and constant cell voltage electrolysis,along with SEM,XRD and oxygen-nitrogen analysis techniques.The effect of graphite anode gas on the deoxidation process was investigated.The research results show that in LiCl-NaCl molten salt system,the oxygen content in tantalum can be effectively reduced by electrolysis,and the deoxidation reactions include Ta₂O₅→Ta(O)+LiTaO₃ and Ta(O)+LiTaO₃→Ta.The molten salt electrochemical deoxidation process employs electrons as the reducing agent,and 10%oxygen is removed by electrolyzing tantalum powder at-2.8 V for 10 h.Besides,electrochemical deoxidation promotes the sintering of tantalum particles.

Taking acidic titanium dioxide waste water formed after the preparation of titanium dioxide as the research object,sodium chloride(NaCl)and diisoocyl phosphate(P204)were used to synergistically extract and recover vanadium from the titanium dioxide waste water.The effects of initial solution pH value,NaCl addition amount,oscillation rate and oscillation time on vanadium extraction rate were investigated.Under the conditions of organic phase composition of 20%P204 and 80%sulfonated kerosene,phase ratio of 1∶1,initial solution pH value of 2.3,NaCl addition amount of 75 g/L,oscillation rate of 220 r/min,and oscillation time of 5 min,the single-stage extraction rate of vanadium reaches 92.38%.However,the single-stage extraction rate of vanadium without NaCl is only 66.67%under the same conditions.

The technology and research progress are reviewed of preparing boiling chlorination burden from electric furnace titanium slag by removing impurities such as calcium and magnesium.The technical characteristics and problems of various methods are analyzed.The main directions of the research on preparing boiling chlorination burden from electric furnace titanium slag by impurity removal in China are pointed out as follows:reducing the silicon content in electric furnace titanium slag by further beneficiation desiliconization from ilmenite,reconstructing the mineral phase by using the sensible heat of molten titanium slag after smelting,recycling the leaching reagents in impurity removal process,and realizing high-efficiency,low-consumption and clean preparation of boiling chlorination burden from electric furnace titanium slag.

The leaching effect of As,Sb and Bi from copper anode slime by composite acid leaching with hydrochloric acid-sulfuric acid-sodium chloride was studied.The effects of chloride ion concentration,hydrogen ion concentration,heating temperature,stirring time,ultrasonic time and solid-liquid ratio on the lea-ching rate of As,Sb and Bi were investigated.The results show that the leaching rate of As,Sb and Bi is better under the conditions of chloride ion concentration of 6 mol/L,hydrogen ion concentration of 6 mol/L,heating temperature of 60℃,stirring time of 3 h,ultrasonic time of 1.5 h and solid-liquid ratio of 1∶9.

The periodic central cracks of large-size radially forged molybdenum alloy bars were analyzed by metallographic microstructure observation, chemical composition analysis, fracture morphology observation, microhardness test, finite element simulation and other methods.The results show that there is slight component segregation in the center of the bar, and severe uneven deformation is the main reason for the center cracks in the bar during forging.By improving the purity of raw materials, homogenizing annealing, and increasing the tempering temperature and time, serious center cracks in large-size molybdenum alloy bars during processing can be prevented to a certain extent.

With Al(NO₃)₃,La(NO₃)₃,Zr(NO3)4 and(NH4)2Mo4O13 as raw materials, the Al₂O₃,La₂O₃ and ZrO₂ doped molybdenum powders were prepared by hydrothermal synthesis, low temperature calcination and two-stage reduction processes.SEM,XRD,EDS and other detection methods were used to analyze the morphology and phase structure of the powders in each preparation stage.The results show that the evolution of molybdenum in the preparation process is h-MoO₃→α-MoO₃→MoO₂→Mo, and the doping of oxides has influence on each stage.The pH value of the mixture is different due to the different pH value of each group after the second phase suspension is mixed with h-MoO₃ suspension, which results in the decomposition of h-MoO₃ with the hexagonal micron column structure to different degrees.The crystal form of h-MoO₃ transforms into α-MoO₃ with layered structure during calcination, the surface of α-MoO₃ in the mixed powder has obvious lamellar structure under the action of the second phase.The morphology of the powder is irregular and MoO₂ particles in the mixed powder have small size and obvious adhesion after the primary reduction.Mo particles are nearly spherical and the second phase can obviously refine Mo particles after the two-stage reduction.The effects of different oxides to refine Mo particles are La₂O₃,ZrO₂ and Al₂O₃ from strong to weak, among which La₂O₃ has the best refining effect, and the average size of La₂O₃-doped Mo particles can reach 1 μm.

The rare earth microalloyed copper wires were prepared by smelting,ingot casting and cold and hot processing,and the effects of La,Y,Te,Zr and Ag microalloying on the mechanical properties,electrical properties and microstructure of copper wires were studied.The results show that the elongation of the microalloyed copper wires reaches 30%and the resistivity is 0.01715Ω·mm2/m under the condition of 220~260 MPa yield strength.The rare earth microalloyed copper wires have excellent performance,meeting the service requirements of copper wires for transformers.

Nano VC whiskers were prepared by using ammonium metavanadate,xylose,etc.as precursor materials with carbothermal reduction method.The effects of type and dosage of halogenation agents on the preparation of nano VC whiskers were studied by SEM,TEM and XRD.The results show that nano VC whiskers with about 100 nm diameter,smooth surface and good morphology can be prepared at 1000℃for 2 h by adding 10%NaF as the halogenation agent.NaF is the most ideal halogenation agent for preparing VC whiskers in six kinds of halogenation agents.The dosage of halogenation agents has an important influence on the preparation of nano VC whiskers.The optimal dosage of NaF is 10%.Too little NaF cannot promote the growth of VC whiskers,while too much NaF will inhibit the growth of VC whiskers.