At present,the energy density of lithium iron phosphate,the mainstream cathode material for lithium ion batteries in the market,has almost reached its limit,while lithium manganese iron phosphate is expected to break this bottleneck.Lithium ion batteries with lithium manganese iron phosphate as the ca-thode material offer advantages of high voltage,high energy density,and better low-temperature stability.This paper describes the characteristics of structure and performance of lithium manganese iron phosphate,introduces the latest research progress in its preparation methods,and discusses the deficiencies of these methods.Finally,this paper looks ahead to the future development directions and application prospects of lithium manganese iron phosphate.

The process flow and design parameters are introduced of the wastewater treatment in the extraction section for raw material preparation before the synthesis of a ternary precursor in Sichuan Province.According to the water quality characteristics of the wastewater,a treatment process combining air flotation deoiling,chemical precipitation removal of heavy metals,ozone catalytic oxidation removal of COD,resin deep removal of heavy metals and MVR salt evaporation was adopted to produce industrial anhydrous sodium sulfate product(purity of 95%,classⅢqualified product),and achieve zero discharge of wastewater,which provides important reference value for the treatment of similar industrial wastewater.

Rare earths serve as key raw materials to support high-end technological innovation and the development of new energy industry.Thus,it is imperative to address the financing difficulties faced by small and medium-sized enterprises(SMEs)in the rare earth supply chain,strengthen China′s rare earth industry chain,and better safeguard the national strategic interests.As an innovative financing method,supply chain finance has become a major means to realize SME financing credit,but the credit risk issue remains one of the most critical issues that need to be solved in financing decision.Therefore,this paper proposed a hybrid augmented machine learning algorithm.First,the support vector machine(SVM)algorithm was optimized using the dynamic lens imaging inverse learning improved marine predator algorithm(IMPA),and then the optimized SVM was integrated using the AdaBoost algorithm to build an AdaBoost-IMPA-SVM model.The model was employed to evaluate the financial risk of the supply chain and re-establish the financial risk system indicators of the supply chain.Then,special effects were selected through correlation analysis,and 140 samples from 52 Chinese listed SMEs in the computer communication and other manufacturing industries during 2019—2021 were selected and input into the model as characteristic variables.The results of simulation experiments verify that the model has better classification and identification perfor-mance compared with other credit risk evaluation models.

Orthogonal experiments were used to determine the optimal process conditions for oxygen-pressure water leaching of molybdenite concentrate,and the kinetics study of MoS₂ oxidative decomposition reaction during oxygen-pressure water leaching was carried out under the optimal process conditions.The results show that under the optimal conditions of ore particle size D₉₀=46 μm,oxygen pressure of 1.1 MPa,temperature of 230 ℃,liquid-solid ratio of 7∶1,and reaction time of 1 h,the highest molybdenum conversion ratio can reach 99.77%,with the copper leaching ratio of 97.56%,and the iron leaching ratio of 88.71%.Within the leaching temperature range of 170~230 ℃(other process conditions are set at the above-mentioned optimal values),the oxidative decomposition reaction of MoS₂ in molybdenite concentrate follows the unreacted nucleus shrinking model and is primarily controlled by chemical reaction with an apparent activation energy of 45.71 kJ/mol.

Using the leachate of the decarbonized slag of high-carbon stone coal after blank roasting and acid leaching as raw material,the vanadium extraction and stripping processes were studied using extractant N235 and stripping agent Na₂CO₃.The results show that under the optimal extraction conditions of an extraction solution pH of 2.3,an organic phase composition of 15%N235+5%sec-octanol+80%sulfonated kerosene,a phase ratio(O/A)of 1∶4,an extraction time of 4 mintues,an oxidant sodium chlorate dosage being 0.05 times the mass of V₂O_5,and five extraction stages,the vanadium extraction rate reaches 99%.The optimal stripping parameters include a Na₂CO₃solution concentration of 8%,a stripping phase ratio(O/A)of 4∶1,a stripping time of 10 minutes,and three stripping stages,allowing the stripping rate of vanadium to reach 99.50%.Under these optimal extraction and stripping conditions,the concentration of vanadium is enriched from 4.25 g/L to 68.50 g/L,with a pH value of 8.5 without neutralization.The final product V₂O₅obtained by further precipitation and calcination of vanadium-rich liquid has a grade of 98.95%and low impurity content,meeting the requirements of 98-level V₂O_5inindustry standard of YB/T 5304—2017.

In the flotation of lepidolite ore in strongly acidic pulp system(pH=2~3) using amine collectors,different issues occur,including high consumption of H₂SO_4,serious corrosion of equipment,large viscosity of flotation foam,and difficult wastewater treatment.Using the tungsten-tin separation tailings(lepidolite flotation feed and Li_2O grade of 0.44%) from a polymetallic ore containing tungsten,tin,rubi-dium,and lithium in Hunan Province as the study object,a combined anionic(WJ)/cationic(dodecylamine,DDA) collector was used to conduct flotation recovery of the low-grade lepidolite ore under neutral pulp pH and non-desliming conditions,and the synergistic effects and adsorption mechanism of the combined collector were investigated by atomic force microscope(AFM) and pyrene fluorescence spectrum at microscopic level.The results show that compared with using DDA alone,when the combined WJ+DDA with a mass ratio of 3.5∶1 is used,the collector dosage decreases by 130 g/t,the Li_2O grade increases by 0.35% and the Li_2O recovery rate also increases by 1.41% in the obtained concentrate.Meanwhile,the flotation foam is fresh with less gangue entrainment.The molecules of the combined WJ+DDA collector are densely adsorbed on the surface of lepidolite and barely absorbed on the surface of quartz/feldspar.And compared with using WJ or DDA alone,the combined WJ+DDA collector exhibits greater non-polarity and stronger hydrophobicity,thus possessing higher surface activity.

Using powder metallurgy technology,ODS-Mo-14Re was prepared by adding lanthanum oxide to molybdenum-rhenium alloy.The microstructure and mechanical properties at room temperature and high temperature of the molybdenum alloy tubes before and after the addition of lanthanum oxide were analyzed by EBSD,XRD,Vickers hardness tester,and electro-mechanical universal testing machine.The results show that the addition of an appropriate amount of lanthanum oxide can play an effective role in fine grain strengthening and dispersion strengthening of the molybdenum-rhenium alloy.The addition of 0.3%(by mass) lanthanum oxide reduces the average grain size of the molybdenum-rhenium alloy from 22.6 μm to 7 μm.And when lanthanum oxide is added to the molybdenum-rhenium alloy as a fine dispersed second phase,it increases the dislocation density within the grains,causing dislocations to tangle with each other and hindering dislocation movement,thereby improving strength and plasticity of the molybdenum-rhenium alloy,with a significant dispersion strengthening effect.The tensile strength of Mo-14Re is 725.8 MPa and 195.3 MPa at room temperature and high temperature(1 300 ℃),while that of ODS-Mo-14Re reaches 780.9 MPa and 226.4 MPa,representing increases of 7.6% and 15.9%,respectively,which indicates that the addition of lanthanum oxide significantly improves the mechanical properties at room temperature and high temperature of the molybdenum-rhenium alloy.

Using La(NO₃)₃·6H₂O,Al(NO₃)₃·9H₂O,and Ce(NO₃)₃·6H_2O as the raw materials and C₂H_5NO_(2 ) as a reducing agent,La_1-xCe_xAlO₃(x=0.01,0.02,0.03,0.04,0.05) samples were synthesized by solution combustion method and analyzed by XRD,SEM,UV-Vis DRS,XPS,and XRF.The results show that compared with LaAlO₃ prepared at other temperatures or with different Ce doping amount,La_0.97Ce_0.03AlO₃ prepared at 825 ℃ for 4 h possesses more prominent and distinct XRD characteristic peaks.And the sample exhibits dispersed particles,and a clear contour,with a particle size of 21.59 nm.The absorption of the sample also becomes stronger in the ultraviolet-visible region with a band gap width of 4.86 eV.Ce³⁺ ions have occupied part of the positions of La³⁺ in the LaAlO₃ lattice,with an optimal Ce³⁺ doping concentration of 0.03.Its strongest characteristic peak of the emission spectrum appears at 525 nm,emitting yellow-green light.

To investigate the effects of rare earth Ce on the microstructure and mechanical properties of DH36 ship plate steel,the DH36 ship plate steels with different Ce contents were smelted in a vacuum induction furnace.The effects of Ce on the microstructure,hardness,impact properties,and tensile properties of DH36 ship plate steel were studied using field emission scanning electron microscope,microhardness tester,impact testing machine,and electro-mechanical universal testing machine.The results show that the addition of Ce to the DH36 ship plate steel refines the structure of ferrite and pearlite.The test steel containing 0.009% Ce exhibits the best comprehensive mechanical properties,with the largest increase in its hardness,which is 15.6% higher than the Ce-free test steel.The tensile strength is increased from 581.97 MPa to 643.80 MPa,which is 10.6% higher.And the impact energy is increased from 162.8 J to 174.5 J,7.2% higher.After adding rare earth Ce,the morphology of the tensile and impact fracture of the test steel is improved,and the number of ductile dimples also increases.The type of inclusions on the fracture surface changes from large-sized irregular inclusions to small-sized spherical rare earth inclusions,reducing the stress concentration caused by harmful inclusions and significantly decreasing the number of crack sources on the fracture surface.

In response to the insufficient research on the influence law of rare earth on the corrosion resis-tance of steel and the local corrosion mechanism of rare earth inclusions on ship plate steel,the influence of rare earth Ce content on the microstructure and corrosion resistance of DH36 ship plate steel in a 3.5% NaCl solution was studied using metallographic microscope,scanning electron microscope,laser confocal microscope,and electrochemical workstation.The results indicate that rare earth Ce can refine the grain size of the test steel and reduce the interlayer spacing of pearlite in the test steel.The addition of rare earth Ce transforms the MnS and Al₂O₃+MnS inclusions in the test steel into MnS+CeAlO₃,Mn-Al-O-Ce and Mn-S-Al-O-Ce inclusions.Compared with the test steel without Ce and with 0.001 0% Ce,the corrosion rate of the test steel with 0.009 2% Ce is the lowest,the flocculent corrosion products are the least,the size and number of corrosion pits are the smallest,the surface roughness is relatively small,and it still has a metallic luster in the initial stage.The addition of rare earth Ce increases the corrosion potential and reduces the corrosion current density of the test steel.When the corrosion time is 5 d,the corrosion current density of the test steel with 0.009 2% Ce is the lowest(2.225 × 10^-5 A/cm~2),the corrosion voltage is the highest(-1.057 V),and the corrosion resistance performance is the best.