In the new process of scheelite leaching in H2 SO4-H3 PO4 synergistic system,the phosphorus impurity in the ammonium tungstate solution can be effectively removed by adding magnesium salt into the ammonium tungstate solution obtained by the ammonia dissolution of phosphotungstic acid.However,the residual Mg^2＋in the phosphorus removed solution can easily lead to the excessive magnesium content in the APT product.In order to obtain the product meeting Chinese standard of GB/T 10116—88 APT-0,D850 chelating resin was used to adsorb Mg^2＋from ammonium tungstate solution.At room temperature,different volume of wet resin was loaded into a plexiglass ion exchange column with a diameter of 15 mm.The ammonium tungstate solution containing 200 mg/L Mg^2＋and 220 g/L WO2-4 was passed through the resin bed with the flow rate 1.1 mL/min.The results show that when the volume ratio of ammonium tungstate solution to wet resin is less than 22~25,the concentration of Mg^2＋in the exchanged solution is almost zero,the solution can be deeply purified,and APT product from evaporative crystallization fully meets the requirements of the national standard.Washed by deionized water at room temperature,the Mg^2＋-loaded resins were desorbed with 0.5 mol/L sulphuric acid at a flow rate of 6 mL/min.The desorption rate of Mg^2＋is more than 96.4%,and the resins can be well regenerated.

The smelting process was studied of rare earth and scandium recovery from rare metal associated iron concentrate with 61.26% TFe,0.30% REO and 78.20 g/t Sc2 O3.The results indicate that the proper smelting process parameters are as follows：smelting temperature of 1 500 ℃,smelting time of 60 min,the flux of 2.24%lime and 0.06% quartz,and graphite dosage of 10% as the reducing agent.Under the above conditions,the pig iron with 92.61% TFe and smelting slag with 2.64% REO and 673.11 g/t Sc2 O3 are obtained,the iron recovery of pig iron is 97.99%,and the recoveries of REO and Sc2 O3 of smelting slag are96.98% and 94.86%,respectively.

The distribution and main existent forms of lithium resources in the world are introduced.The current research status of lithium extraction from solid lithium-containing ore at home and abroad in recent years is reviewed from the aspects of sulfuric acid method,sulfate method,chlorination roasting method and sodium carbonate autoclave method.The current status of lithium extraction from salt lake brine is summarized from the aspects of precipitation method,extraction method and adsorption method.The mechanism,advantages and disadvantages of various methods are analyzed,and the direction of improvement is proposed.Finally,the development trend and direction of the technology of lithium extraction from solid lithium ore and salt lake brine are analyzed and prospected.

According to the representative process flowsheet of tellurium recovery from copper anode slime,the research progress is systematically reviewed in the main process steps including roasting,leaching,separation/extraction of tellurium and crude tellurium refining,the advantages and disadvantages of each processing technology are analyzed and compared.The methods of tellurium extraction from the intermediate product of cuprous telluride（Cu2 Te）are also introduced.On this basis,the main problems in tellurium recovery from copper anode slime are pointed out,and the corresponding solutions are proposed.In the end,the development direction of tellurium recovery from copper anode slime is pointed out.

The conditions of ash deposition and coking in waste heat utilization device of high-temperature flue gas from metallurgical furnaces are introduced.The mechanisms of physical and chemical coking of high-temperature flue gas and dust are analyzed.And the effective and practical specific measures are proposed to solve the coking problem of high-temperature flue gas and dust in waste heat utilization device.

The reserves and distribution of rare earth resources in the world are introduced.By analyzing the relationship between supply and demand of rare earth and the balance of supply and demand structure of rare earth,it is pointed out that there are disorderly competition and serious environmental load in China＇s rare earth mining and smelting industry.And other countries are also actively developing rare earth minerals.With the development of new industries,the demand structure of rare earth permanent magnetic materials and phosphors also has according changes,resulting in a certain impact on the supply and demand structure of rare earth in the world,and the future pattern of rare earth supply and demand is expected to be diversified.Finally,the future development mode of rare earth in China is prospected,that is intensive,environmentally friendly,sustainable,high-end applicable and intelligent industrial development based on the domestic demand.

The effects of cold rotary forging on the microstructure and tensile mechanical properties of Nb521 alloy bars for high temperature fasteners were investigated using metallographic microscope,electron backscatter diffractometer and tensile mechanical property test.The results show that with the increase of processing rate of cold rotary forging,the grains of the bar are elongated in the axial direction to form fibrous microstructure,the tensile mechanical properties show an obvious tendency of work hardening,and the strength gradually increases.When the bars with different processing rates are annealed in vacuum at 1 350℃for 1 h,all the microstructures are incompletely recrystallized.The recrystallization ratio of the bar with 60% processing rate is medium,but its average grain size is the smallest and its comprehensive mechanical properties are the best.The grain sizes of the core and the edge of the bar with 60% processing rate are quite different,and the strength of the core is higher than that of the edge in the hard state,but lower than that of the edge in the annealed state.

LaAlO3 infrared radiation ceramic materials doped with Fe ion and Fe-Ni ions in B site were prepared with sol-gel method.The doped LaAlO3 samples were characterized and analyzed by XRD,FTIR,SEM,IR-2,XPS and other means.The results show that all the doped products are perovskite type complex oxides.The infrared emissivity is increased but the increment is small after Fe doping,and the infrared radiation properties are obviously improved after Fe-Ni co-doping.When the doping content of Fe^3＋is 0.25,the infrared emissivity within 3~5μm waveband increases from 0.345 to 0.821.The physical mechanism of the enhancement of infrared emissivity is as follows.There are two compensation mechanisms including the generation of oxygen vacancy and the change of chemical valence after B-site doping.The chemical valence change can produce small polarons from Ni ^3＋Ni 2＋and Fe^3＋Fe2＋,which is contributed to the transition of electrons from the valence band to the conduction band.With the increase of oxygen vacancy concentration,the ratio of the adsorbed oxygen increases,which is beneficial to improve the absorption properties of the ceramic materials in near mid-infrared waveband.Thus,lanthanum aluminate material as the lining material of furnaces can improve the radiation heat transfer in the furnace,and has a broad application prospect.

BiVO4 and Y-BiVO4 semiconductor photocatalytic materials were prepared by one-step hydrothermal method and low temperature calcination,and the structure and properties were characterized and analyzed by XRD,SEM,FT-IR,UV-Vis DSR and PL.The test results show that the crystal form of Y^3＋-doped BiVO4 is transformed from tetragonal phase to monoclinic phase with decahedral grains.Photocatalytic activity test results show that both Y^3＋doping and low temperature calcination could enhance the degradation rate of BiVO4 to RhB.The calcined Y-BiVO4 exhibits higher photocatalytic activity,which is 2 times the degradation rate of uncalcined BiVO4,and the degradation rate of RhB is 86.6% within 120 min.

The three kinds of bluish-green,yellowish-green and orange-red long afterglow luminescent materials were prepared by high-temprature solid-state synthesis with aluminum hydroxide prepared from industrial sodium aluminate solution as the raw material.The phase composition of the obtained samples was determined by X-ray diffractometer.The excitation and emission spectra of the samples were determined by fluorescence spectrophotometer.The determined results show that the alteration of Sr/Al molar ratio in precursor reactants causes the crystal structure of the samples to change and thus affect their luminescent properties.When Sr/Al molar ratio is 2/7,1/2 and 3/2,respectively,the synthesized samples are pure Sr4 Al14 O25∶Eu2＋,Dy^3＋,SrAl2 O4∶Eu2＋,Dy^3＋and Sr3 Al2 O6∶Eu2＋,Dy^3＋in turn,and they have bluishgreen,yellowish-green and orange-red afterglow color,respectively.All the excitation and emission spectra of the three prepared samples are broadband spectra,and they can be effectively excitated by the natural light such as sunlight and daylight lamps.With the increase of Sr/Al molar ratio,the strongest excitation peak is redshifted from 350 nm to 450 nm,and the strongest emission peak is also redshifted from 460 nm to 600 nm.