In view of the fact that it is difficult to prepare ultra-coarse grain cemented carbides with WC average grain size(d_WC)greater than 8μm by traditional ball milling method,this paper adopted two specifications(ϕ5.5 mm andϕ10.5 mm,aspect ratio 1.5∶1)of rod-shaped grinding media combined with different wet grinding time,so that the wet grinding strength can maintain at the degree of only mixing without excessive crushing,and the ultra-coarse-grained cemented carbides with d_WC greater than 8μm were successfully prepared.Their microstructure and physical and mechanical properties were then analyzed.The results show that the crushing and mixing effect of the large rod grinding media on the material is inferior to that of the small rod.With the increase of the small rod grinding media mass and the wet grinding time,the porosity and Co phase uniformity of the alloy are obviously improved,but the d_WC decreases gradually.With the decrease of d_WC,the hardness and strength of the alloy increase,while the thermal conductivity and the fracture toughness decrease.The ultra-coarse-grained cemented carbide with porosity of A02B00 level and d_WC of≥8μm can be prepared under the conditions of small rod and wet grinding time of 12 h or large rod and wet grinding time of 20 h.The hardness value is maintained at about 900 HV₅₀,the bending strength value exceeds 1800 MPa,the thermal conductivity exceeds 140 W/(m·K),and the maximum fracture toughness value is 21.6 MPa·m^1/2.Compared with super-coarse-grained cemented carbide,ultracoarse-grained cemented carbide shows better inhibition and hindrance to the generation and propagation of cracks,along with superior fracture toughness.

To improve the comprehensive properties of WC-based cemented carbides,WC-based cemented carbides with different mass fractions(0,0.6%,0.8%,1.0%,1.2%and 1.4%)of NbC added were prepared via pressureless melt infiltration using Cu-10Ni-5Mn-3Sn as the binder alloy.The effects of different NbC contents on the microstructure and mechanical properties of cemented carbides were analyzed by scanning electron microscope,energy dispersive spectrometer,X-ray diffractometer,universal testing machine,and Rockwell hardness tester.The action mechanism of NbC as an inhibitor was also explored.The experimental results show that the dissolution-precipitation process of WC in the binder phase is slowed down by adding an appropriate content of NbC(≤1.0%),resulting in grain refinement.When NbC is added in excess(>1.0%),the brittle Ni₂W₄C,Nb₄Ni₂C,and(Nb,W)C gradually form.As the NbC content increases,the average grain size of WC in the alloy first decreases and then increases,the hardness and bending strength first increase and then decrease,and the fracture toughness first decreases and then increases.After adding 1.0%NbC,the hardness and bending strength of the alloy reach their maximum values of 93.4 HRA and 1808.8 MPa,respectively.At this time,the fracture morphology of the alloy is mainly brittle fracture,and the fracture toughness value is relatively low.

为适应我国信息化建设需要,扩大读作者学术交流渠道,《稀有金属与硬质合金》已许可中国知网、万方数据、维普资讯、超星信息、长江文库、有科有数、钛学术及新华网学术等数据库以数字化方式复制、汇编、发行、信息网络传播整刊全文。本刊支付的稿酬已含上述数据库的著作权使用费,所有作者向本刊提交文章发表之行为视为同意上述声明。如有异议,请在投稿时说明,本刊将按作者说明处理。

With the depletion of high-quality tungsten ore resources,molybdenum-rich tungsten ore has gradually become the main production raw material for tungsten smelting enterprises in China.However,tungsten and molybdenum have similar properties and exhibit similar reaction behaviors during tungsten ore smelting,which increases the difficulty of removing molybdenum in production and often leads to excessive molybdenum content in ammonium paratungstate(APT)products.Therefore,elucidating the migration laws of tungsten and molybdenum in the tungsten ore smelting process has profound significance.This article applies the element flow analysis method to track tungsten and molybdenum in the process of producing APT through alkaline decomposition of tungsten ore,revealing their distribution patterns in various materials.The results indicate that using a mixed concentrate of wolframite and scheelite as the raw material,the distribution ratios of W in dust,tungsten slag,dephosphorization slag,post-exchange solution,primary solution,molybdenum removal slag,crystallization mother liquor,and APT products are 0.01%,1.40%,1.97%,1.93%,0.95%,0.01%,2.34%,and 91.39%,respectively.The distribution ratios of Mo in tungsten slag,dephosphorization slag,molybdenum removal slag,and APT products are 79.88%,0.61%,15.24%,and 0.73%,respectively,while its distribution ratios in the post-exchange solution and crystallization mother liquor are 0.61% and 2.93%,respectively.

Samarium iron nitride(Sm₂Fe₁₇N_x)alloy exhibits irreplaceable material advantages in miniaturized permanent magnet actuators and high-temperature motors owing to its exceptional permanent magnetic properties and high-temperature stability.Sm-Fe alloy is regarded as the precursor of the next-generation rare-earth permanent magnet material Sm₂Fe₁₇N_x,and the innovation in its preparation process remains a critical research focus in materials engineering.Molten salt electrolysis method has emerged as a cutting-edge technique for Sm-Fe alloy synthesis,leveraged for its unique capability in in-situ alloying and controlling ability of elemental distribution.This article systematically reviews research progress and existing challenges in the preparation of Sm-Fe alloy by molten salt electrolysis method.Special emphasis is placed on elucidating the electrochemical formation mechanisms of Sm-Fe alloy in chloride-based and fluoride-based molten salt systems.Key scientific issues,including the electrochemical reduction pathways of Sm³⁺and interfacial diffusion kinetics of alloy phase,are comprehensively analyzed.Finally,future research directions aimed at optimizing molten salt electrolysis method for high-performance Sm-Fe alloy fabrication are proposed.

Dy is extensively employed in low-carbon technologies,but its limited global reserves make the efficient separation of Dy from raw ore leachates and waste solutions crucial for the sustainable development of the rare earth industry and its related sectors.In this study,a solution of DyCl₃dissolved in hydrochloric acid was used as the aqueous phase,with P204 as the extractant and kerosene as the diluent,to investigate the extraction behavior of P204 for Dy(Ⅲ).The effects of various process parameters(extractant concentration,hydrochloric acid concentration,O/A phase ratio,extraction time,and extraction temperature)on the extraction rate of Dy(Ⅲ)were systematically examined and the extraction mechanism was further elucidated through infrared spectroscopy.The results indicate that the extraction rate of Dy(Ⅲ)initially increases and then stabilizes with rising P204 concentration,O/A ratio,and extraction time.In contrast,increasing the concentration of hydrochloric acid used to dissolve DyCl₃leads to a significant decline in Dy(Ⅲ)extraction rate,with the extraction process nearly ceasing at an HCl concentration of 3 mol/L.Temperature variations between 5℃ and 50℃ have minimal impact on Dy(Ⅲ)extraction rate.The optimized extraction conditions are determined as follows:P204 concentration of 0.2 mol/L,hydrochloric acid concentration of 0.02 mol/L,phase ratio of 1,room temperature,and extraction time of 60 min.Under these conditions,the extraction rate of Dy(Ⅲ)reaches nearly 90%.The essence of the extraction process is the formation of a dimer of P204 molecules,with the P=O double bond as the active site,where lone pair electrons of oxygen coordinate and bind with Dy(Ⅲ),accompanied by ion exchange between H⁺in the P OH group and Dy(Ⅲ),forming a stable neutral extraction complex that transfers to the organic phase.

In view of the difficulty in vanadium extraction from stone coal vanadium ores due to their complex structure,this study aims to achieve deep extraction and efficient recovery of vanadium resources.Taking a stone coal vanadium ore from a certain area in Shaanxi Province as the research object,and based on the analysis of the occurrence state of vanadium in the ore and its process transformation,a combined process of barium salt roasting-acid leaching-solvent extraction-ammonium salt vanadium precipitation was employed for vanadium extraction.Through parameter optimization,an optimal vanadium extraction effect was achieved.The research results show that the optimized process parameters are as follows:In the roasting stage,the grinding fineness is 60% passing 0.074 mm,the barium sulfate dosage is 5%,the roasting temperature is 900℃,and the roasting time is 4 h.In the leaching stage,the sulfuric acid dosage is 5%,the liquid-solid ratio is 1.5∶1,the leaching temperature is room temperature,and the leaching time is 2 h.Under these conditions,the V₂O₅leaching rate reaches over 82%.The vanadium-containing leachate is oxidized by sodium chlorate and then extracted using a 7.5%N235+5%sec-octanol+82.5% sulfonated kerosene extraction system,with an vanadium extraction rate of 99.45%.The obtained loaded organic phase is stripped with 10% sodium carbonate solution,and the vanadium stripping rate reaches 99.71%.After impurity removal with calcium chloride,vanadium precipitation with ammonium chloride,and calcination,the stripping solution yields a vanadium pentoxide product with a purity of 99.32%,which meets the requirements of grade 99 in the industry standard(YB/T 5304—2017).This study provides a technical path and data reference for vanadium extraction from similar stone coal vanadium ores.

With the rapid development of the global new energy industry,the demand for lithium has increased dramatically.Salt lake lithium resources with large reserves and low production costs have become the main source of lithium products.However,the development of lithium resources in salt lake is facing the double challenges of technology and environment,in which the separation of magnesium and lithium from brine with a high magnesium-lithium ratio is the key technical bottleneck.The adsorption method has attracted much attention in the field of lithium extraction from salt lake due to its advantages of strong adsorption capacity,high selectivity,simple preparation,low pollution and reusability of adsorbents.This paper reviews the research progress of the adsorption method for lithium extraction from salt lake,introduces the working principles and characteristics of inorganic adsorbents,organic adsorbents and composite adsorbents in detail,analyzes the problems and challenges faced by this method,and looks forward to its future development direction.

The smelting of complex multi-metal lead-zinc concentrates is one of the major challenges in modern non-ferrous metal metallurgy.Traditional single-metal smelting methods cannot economically and efficiently process this mineral to recover lead and zinc.The ISP process has several advantages,including strong raw material adaptability and high comprehensive resource utilization efficiency.It is particularly advantageous in handling complex multi-metal lead-zinc concentrates.In recent years,with technological upgrades and the introduction of advanced techniques such as oxygen-enriched sintering,oxygen-enriched reduction smelting,oxygen-enriched bottom-blown blister copper recovery,and efficient green recovery of germanium and indium,Shaoguan Smelting Plant has successfully strengthened and optimized the entire flow of the ISP process.The main advantages of the upgraded ISP process include:Firstly,it enhances the process's adaptability to raw materials,particularly in significantly improving its ability to handle complex multi-metal lead-zinc concentrates.Secondly,it facilitates the simultaneous processing of urban mineral resources.By employing targeted recovery processes for urban mineral resources and various smelting byproducts,the upgraded ISP process enables the efficient recovery of valuable metals such as copper,gold,silver,indium,and germanium,delivering good economic,environmental,and social benefits.

近日,在由中国采购与招标网、中国名企排行网于北京主办的“2025(第19届)招投标领域年度聚焦活动”中,“2025工程勘察设计行业综合实力百强榜单”正式发布。长沙有色冶金设计研究院有限公司(简称长沙有色院)凭借卓越的综合实力、突出的科技创新成果和广泛的行业影响力,成功入选该权威榜单,彰显了其在工程勘察设计领域的领先地位与强劲发展势头。