By thermodynamic calculations of reactions of MgCl₂and AlCl₃with rare earth concentrates,Xray diffractometer(XRD)and inductively coupled plasma optical emission spectrometer(ICP-AES),the chlorination capabilities of MgCl₂and AlCl₃were compared,and the phase composition of the reaction products between Bayan Obo rare earth concentrate and MgCl₂or AlCl₃was determined,as well as the contents of rare earths and thorium in the filtrate after water leaching of the products.The study also investigated the chlorination effects of MgCl₂and AlCl₃on rare earth oxides(La₂O₃,CeO₂,Nd₂O₃,Pr6O11,etc.)and ThO₂,as well as their enrichment effects on Th and Ce.The results indicate that AlCl₃has a greater chlorination ability towards rare earth concentrate than MgCl₂,but the reaction products contain fluorinated and phosphorylated rare earths,which prevents effective enrichment of cerium and thorium.The optimal conditions for separating rare earths and thorium from Bayan Obo rare earth concentrate by roastingleaching are as follows:molar ratio of RE in rare earth concentrate to MgCl₂of 1∶1.3,roasting time of 4 h,roasting temperature of 700℃,and water leaching time of 1 h.Under these conditions,the enrichment rate of thorium reaches 82.5%,and the enrichment rate of cerium reaches 95.4%.

In response to issues such as the lack of coordination among upstream and downstream enterprises and low resource allocation efficiency in the industrial chain of the rare earth industry clusters,the network collaborative manufacturing technology and system for rare earth industry clusters are proposed.It constructs an integration mechanism for collaborative design,manufacturing,and service and intelligent decision-making methods for enterprises.This system supports the deep integration of information,operations,and resources across the entire manufacturing chain,enabling collaboration and iteration across the whole operation process of R&D,supply,production,sales,and service and the entire product lifecycle.It provides technical support for establishing a network collaborative manufacturing system that integrates design,manufacturing,and service and facilitates seamless collaboration between the industrial chain and the market.The effectiveness of the above method in improving enterprise resource allocation efficiency and promoting inter-enterprise collaboration is illustrated through demonstrative application cases.

The ion exchange method was used to purify the acid leaching solution of power generation ash from high-carbon stone coal vanadium ore after blank roasting and enrich vanadium.The influence of different factors on vanadium adsorption and desorption was studied,and the optimal process conditions for adsorption and desorption were determined.The results show that the acid leaching solution has a pH value of 2.3,and can directly undergo ion exchange without neutralization.The order of vanadium adsorption capacity of various resins is D201>D380>D314>D202,the mixed desorption agent of NaOH and NaCl is the best in the desorption process,and the appropriate mass ratio of the two is 3∶1.The optimal dynamic adsorption conditions of D201 resin are as follows:the sodium chlorate dosage is 0.05 times the mass of V₂O₅,and the feed rate per hour is 2 times the resin volume.The V₂O₅adsorption capacity is 186 mg/g and 283 mg/g,respectively when c/c₀value is 0.5 and 0.8,and the adsorption rate is 98.53%when the resin is penetrated.When the D201 resin is desorbed with 6%NaOH+2%NaCl solution as the desorption agent,and the volume ratio of desorption solution to wet resin is 4.36,the V₂O₅content of the desorption solution reaches a peak of 75.46 g/L.When the volume ratio of desorption solution to wet resin is 7.44,the desorption rate of vanadium reaches 99.31%.The vanadium adsorption capacity of the desorbed D201 resin after regeneration by HCl is comparable to that of the new D201 resin.V₂O₅product with purity of 98.98%can be prepared by impurity removal,neutralization,vanadium precipitation and calcination of vanadium-rich solution obtained by desorption.

Spraying powders with WC particle sizes of 1μm and 0.5μm were used to prepare two kinds of WC-10Co4Cr coatings.By means of testing metallographic microstructure,friction coefficient,wear scar morphology and potentiodynamic polarization curves of WC-10Co4Cr coatings,friction and wear properties of the coatings under high loading force of 1000 N were studied,and corrosion resistance of the coatings in sodium chloride solution with different mass fractions was investigated.The results indicate that compactness,microhardness and fracture toughness of the coating prepared by spraying powder with smaller WC particle size are all higher than those of the coating with larger WC particle size.When loading force is 150 N,wear scars of these two coatings are shallow and their difference in wear volume is small,so it is hard to compare their wear resistance.Under loading force of 1000 N,wear resistance of the coating with smaller WC particle size is obviously higher.With the increase of friction time,the friction coefficient of the coating surface gradually decreases,and the wear mechanism is mainly abrasive wear.The friction coefficient of the coating with larger WC particle size increases with friction time,and the wear mechanism of the surface includes adhesive wear and abrasive wear.As mass fraction of sodium chloride in solution increases from 1%to 10%,corrosion potential of the coating with smaller WC particle size is higher than that of the coating with larger WC particle size,and the corrosion resistance of the former coating is better.When the mass fraction of sodium chloride is 3.5%,difference in corrosion potential between these two coatings is highest,and the distinction in corrosion resistance is most apparent.

Ultrafine Ti(C,N)-based cermets with different contents of(Ti,W)C solid solution powder were prepared by low pressure sintering.The effects of(Ti,W)C on the microstructure and mechanical properties of Ti(C,N)-based cermets were systematically studied.The results show that using(Ti,W)C instead of TiC+WC can lead to the formation of white core/ring structure in the microstructure of the cermets,and inhibit the formation of black core/ring structure.At the same time,the morphology of the hard phase changes from cuboidal to spherical.The Vickers hardness and fracture toughness of the cermets can be improved while keeping the bending strength unchanged.Under the condition of low(Ti,W)C content(2.5%~10%),with the increase of(Ti,W)C content,the size of the black core of the cermets decreases,and the white core/gray ring structure increases.The addition of(Ti,W)C makes the microstructure more uniform,enhancing the intergrain bonding force.And the hardness of the cermets increases gradually,while the bending strength and fracture toughness increase at first and then decrease.When the content of(Ti,W)C is 7.5%,the cermet has the best comprehensive mechanical properties,and the bending strength and fracture toughness are 2212 MPa and 9.0 MPa·m^1/2,respectively.

(Ti,Cr,V,Nb,Mo)(C,N)high-entropy ceramic solid solution powders were prepared via mechanical alloying plus carbothermal reduction-nitridation method with TiO₂,Cr₂O₃,V₂O₅,Nb₂O₅,MoO₃and carbon black as raw materials.The phase composition and microstructure of the reaction products were characterized using X-ray diffractometer(XRD)and scanning electron microscope(SEM).The results show that high-quality(Ti,Cr,V,Nb,Mo)(C,N)high-entropy ceramic solid solution powders with an average particle size of about 3μm,uniform element distribution and single phase composition were successfully synthesized at the carbothermal reduction-nitridation temperature of 1600℃with the ball milling speed and time of 600 r/min and 120 min.Carbonthermal reduction-nitridation temperature is the main factor affecting the synthesis of high-entropy ceramic solid solution powders,followed by ball milling speed,and the ball milling time has the least effect.Increasing carbonthermal reduction-nitridation temperature,ball milling speed and ball milling time are beneficial to solid solution of elements,but has a negative effect on inhibiting grain growth.

The influence of Mo content on the microstructure,mechanical properties,and wear resistance of(Ti_42.5Zr_42.5Nb₁₀Ta₅)_10-xMo_x(x=0,3,5,7)high-entropy alloys(HEAs)were systematically investigated.The results show that there is a single BCC phase in the HEAs.With the increase of Mo molar fraction from 0 to 7%,the lattice distortion of HEAs increases,the nanohardness increases from(2.33±0.09)GPa to(4.93±0.09)GPa,the Rockwell hardness increases from(27.76±0.74)HRC to(40.01±0.82)HRC,the Vickers hardness increases from(247.4±6.2)HV to(350.1±7.4)HV,and the wear rate decreases from 9.85×10^-5mm³/(N·m)to 3.5×10^-5mm³/(N·m),which decreases by 64.5%.The wear mechanisms of HEAs include abrasive wear,oxidation wear and adhesive wear.With the increase of Mo content,the wear mechanism gradually changes from abrasive wear to adhesive wear and oxidative wear.

Based on the domestic and foreign literature,the influence of grain size and texture on the sputtering yield of tantalum targets is analyzed,and it is considered that the tantalum target with fine and uniform grains has relatively high sputtering yield.High purity tantalum ingots were used to prepare tantalum targets through large deformation forging combined with rolling and vacuum annealing.The microstructure,grain size,and texture composition of the tantalum targets were analyzed using metallographic microscope and EBSD technology.The results indicate that by increasing the forging deformation of the ingot,the tantalum target can obtain fine and uniform grains in the thickness direction,and its texture is uniformly distributed randomly in the thickness direction.

In order to improve the poisoning resistance of ZrCo alloy against CO impurity gas,ZrCo alloy particles were embedded into SiO₂matrix by SiO₂sol coating method to prepare ZrCo/SiO₂composites with different mass ratios.The phase composition,micro-morphology,and elemental composition of the samples were characterized by X-ray diffractometer,scanning electron microscope,transmission electron microscope,and energy-dispersive X-ray spectrometer.The effects of CO concentration and SiO₂coating ratio on the hydrogen absorption kinetic performance of ZrCo/SiO₂were investigated by using a hydrogen storage material performance test device in a mixed H₂/CO atmosphere,and the hydrogen absorption behavior of the samples was analyzed by kinetic model.The experimental results show that ZrCo hydrogen storage alloy particles are well bonded with the SiO₂matrix and uniformly distributed in the matrix.The SiO₂coating effectively improves the hydrogen absorption rate of ZrCo alloy in H₂/CO atmosphere.When the mass ratio of ZrCo/SiO₂is 1∶1.5,it takes only 5 h for the composite to reach the saturation hydrogen absorption capacity in H₂containing 0.5%(molar ratio)CO,whereas it takes 55 h for the uncoated ZrCo.Therefore,the ZrCo/SiO₂composites have good CO poisoning resistance and certain cycling pulverization resistance.

Li₂CO₃was prepared by carbonate precipitation from lithium-containing wastewater produced in the process of producing Al2O3 from fly ash with hydrochloric acid method.The effects of lithium precipitation temperature,stirring rate and feeding rate on the purity and particle size of Li₂CO₃were studied.The Box-Behnken response surface method was used to optimize the preparation process of Li₂CO₃.The results show that increasing lithium precipitation temperature is beneficial to the growth and purity of Li₂CO₃grains,and Li₂CO₃is easy to form rod-like crystal at higher temperatures.Stirring rate has little effect on the purity of Li₂CO₃products,and suitable stirring rate is conducive to the growth of Li₂CO₃crystal.The lower feeding rate can promote the full growth of Li₂CO₃crystal and reduce the probability of peritectic phenomenon.The optimum conditions for Li₂CO₃preparation are lithium precipitation temperature of 90℃,stirring rate of 200 r/min and feeding rate of 2%/min.The Li₂CO₃prepared under the optimum conditions has the best quality with purity of≥96.71%and average particle size of≤7.35μm.