The denitration catalyst was prepared by impregnating the active components of rare earth tailings onto activated carbon particles.The influence of flue gas temperature,catalyst particle size and NH3/ NO ratio on the SNCR denitrification efficiency of the flue gas produced from high temperature coal-fired circulating fluidized bed boiler was investigated.The content of flue gas components was determined by flue gas analyzer combined with infrared spectrum analysis and then denitrification rate was calculated.The properties and microstructure of the catalyst were characterized by TG,SEM,XRD,TPD and TPR.The results show that the prepared catalyst exhibits high porosity,large specific surface area and good gas adsorption and desorption properties.Flue gas temperature and ammonia nitrogen ratio are important factors affecting the denitrification rate.With the increase of flue gas temperature,denitrification efficiency increases first and then decreases.With the increase of NH3/NO ratio,the decrease of catalyst particle size and the increase of catalyst addition,denitrification efficiency increases first and then decreases.The presence of the catalyst plays a significant role in improving the SNCR denitration efficiency of the coal fired circulating fluidized bed boiler flue gas.A part of Fe,Ce,La,Nd,Pr and other components of the catalyst are easily combined with activated carbon at high temperature to form a co-melt,which is conducive to the progress of the joint synergistic catalytic denitrification reaction.The prepared denitrification catalyst has higher specific surface area,acid content and reducibility than the raw ore.

接北京大学图书馆《中文核心期刊要目总览》2017版编委会通知,由中国有色金属学会和长沙有色冶金设计研究院有限公司共同主办、长沙有色冶金设计研究院有限公司主管的《稀有金属与硬质合金》期刊入编《中文核心期刊要目总览》2017年版(即第8版)之冶金工业类核心期刊。这是本刊自2008年起连续第4次入编《中文核心期刊要目总览》。

Tungsten powder was mixing with carbon by double cone mixer and vertical high speed mixer, the effects of parameters of the new carbon addition process by double cone mixing and stirring mixing on the quality of W+C mixture were studied,and the uniformity of carbon distribution in W+C mixture was analyzed by range analysis.The results show that the uniformity of carbon distribution of W+C mixture produced by double cone mixing and stirring mixing process is better than that of traditional ball milling mixing process.The W+C mixture with good carbon uniformity can be produced under the conditions of 12 r/min operating velocity,50% filling rate,5hmixing time,alternating operation from positive to negative direction,and 4min stir mixing time.

The latest development is reviewed of separation and recovery technologies for complex mineral resources containing molybdenum,lead and zinc, etc. Combined with research results from the authors＂ re- search group on separation and recovery of complex minerals containing molybdenum,lead and zinc, etc by electro-oxidation leaching, the application prospects, research focus and development direction are discussed of electro-oxidation leaching technology in the comprehensive separation and recovery of complex minerals.

Abstract.Selective separation of vanadium and tungsten from the simulated NaOH leaching solution of waste SCR denitration catalyst by anion exchange resin was studied. The effect of solution pH change on adsorption behavior of vanadium and tungsten onto the resin was investigated. The experimental results show that solution pH change has little influence on W adsorption under the alkaline condition,but has re- markable influence on V adsorption. When pH increases from 8 to 12, the main ion form of V is trans- formed from V4O12^4- to HVO4^2- , resulting in greatly reduced adsorption ability of V onto the resin. When pH increases from 12 to 14,the increase of OH^- concentration becomes the main factor affecting the ad- sorption of V and W. Due to the adsorption capacity of WO4^2-〉VO4^3-〉OH^- ,the inhibition effect of in- creased OH^- concentration on V adsorption is more obvious,resulting in further weakening of V adsorp- tion. As pH increases from 8 to 14,W/V separation coefficient increases from 0. 146 to 2.36. When pH is equal to 14 and the loaded resin is eluted with a mixed solution of 1 mol/L NaOH ＋ 2 mol/L NaCl,the maximum desorption concentration of W can reach 84 g/L,while the maximum value of V is not more than 2 g/L. As a result,the separation of tungsten and vanadium is achieved to some extent,tungsten is enriched to a certain extent,and the desorbed liquid can be used as a mother liquid for the subsequent calcium pre- cipitation or crystallization process.

Using a 200 L front chamber extraction tank without batiles as the model,and based on the dis- tance of the original agitator from the bottom of the mixing chamber （installation depth） b= 60 mm, the mixing process of feed liquid and P507 in the rare earth mixing chamber was simulated at 5 mm intervals through fluid dynamics Fluent software. Suction pressure, suction flow velocity and agitating power were used as evaluation criteria to analyze the effect of installation depth on suction performance of the agitator through the simulation analysis with different agitator installation depth. The optimized installation depth b = 50 mm is determined,which provides theoretical guidance for on-site debugging and installation of agita- tors. The results from simulation analysis show that when the installation depth keeps 50 mm,the suction negative pressure is --140.2 Pa, the suction flow velocity is 1.25 m/s,and the agitating power is 105.68 W. The results of simulation analysis are successfully applied in the factory, and the consistency between the simulation analysis conclusions and the on-site test results is verified at the same time.

Research status is reviewed on the application,the preparation method of molten salt electrolysis and the electrochemical mechanism of Dy metal and some typical Dy alloys. The current research progress is analyzed in preparation technology of Dy metal and Dy-Al,Dy-Mg,Dy-Ni,Dy-Fe,Dy-Cu alloys at home and abroad. The development trend of Dy alloy preparation by molten salt electrolysis is prospected.

接北京大学图书馆《中文核心期刊要目总览》2017版编委会通知,由中国有色金属学会和长沙有色冶金设计研究院有限公司共同主办、长沙有色冶金设计研究院有限公司主管的《稀有金属与硬质合金》期刊入编《中文核心期刊要目总览》2017年版（即第8版）之冶金工业类核心期刊。这是本刊自2008年起连续第4次入编《中文核心期刊要目总览》。

Using ammonium tungstate, cupric nitrate trihydrate and citric acid as raw materials, tungsten- copper oxide precursor was synthesized by sol-gel self-propagating combustion and then reduced to tung- sten-copper composite powder with hydrogen gas. Cold mold pressing and sintering in hydrogen were fol- lowed to prepare tungsten-copper composites. The composition and properties of the precursors and the re- duced powders were characterized by XRD, SEM and laser particle size analyzer. The morphology and phys- ical properties of the sintered billet were also studied. The results show that the sol-gel self-propagating combustion method can be used to prepare tungsten-copper composite powders with average particle size of 3.5-7.1 /μm and uniformly distributed tungsten and copper particles of 23-42 nm size. W-50Cu sintered at 1 300 ℃ has the highest relative density and conductivity,reaching 99.52% and 68.96%IACS, respec- tively. W-20Cu sintered at 1 300 ℃ has the highest Vickers hardness,reaching 229.

The （FeCrCo/Ni）5-SiTiNbMoW high-entropy alloy coatings were successfully prepared on the surface of the tool steel by laser cladding technology. The microstructure,composition, phase and hardness of the coatings were analyzed and tested by SEM/EDS, XRD and microhardness tester. The results show that the （FeCrCo）5-SiTiNbMoW coating contains BCC main phase,and a small amount of MC phase and Laves phase. The （FeCrNi）5-SiTiNbMoW coating contains FCC main phase and a small amount of MC phase and Laves phase. The two coatings are dominated by dendrites,while the （FeCrNi）5-SiTiNbMoW coating also has eutectic microstructure. The microhardness of the （FeCrCo）5-SiTiNbMoW high-entropy alloy coating is slightly higher than that of the （FeCrNi）5-SiTiNbMoW high-entropy alloy coating.