Tungsten and vanadium were recovered from spent SCR denitration catalyst by high pressure leaching with Na2CO3.The effects were investigated of roasting pretreatment temperature,type and dosage of the leaching additive,Na_2CO_3 dosage,liquid-solid ratio,leaching time and temperature for tungsten and vanadium leaching.The phases of spent SCR denitration catalyst were analyzed by XRD characterization before and after leaching.The results show that spent SCR denitration catalyst can be leached without roasting pretreatment,and the optimized experimental conditions are as follows:Na_2CO_3addition of 20%,NaOH addition of 8%,liquid-solid ratio of 2∶1,leaching time of 2hand leaching temperature of 230 ℃.Under the above conditions,the leaching rates of tungsten and vanadium reach 75.06% and 89.35%,respectively.In addition,the XRD analysis results show that titanium exists mainly in the form of anatase TiO_2 in spent SCR denitration catalyst,and high-temperature roasting can promote TiO_2 transition from anatase to rutile,inhibiting tungsten and vanadium leaching.Part of tungsten may exist in TiO_2 in the form of solid solution,and therefore the microstructure of TiO_2 should be destroyed by strengthening leaching conditions to further improve the leaching rate of tungsten.

Experimental study was carried out on bioleaching of very low-grade molybdenum tailings with acidithiobacillus ferrooxidans and moderately thermophilic sulfobacillus sibiricu,respectively.The influences were investigated of the presence and type of bacteria on molybdenum tailing leaching.Molybdenum concentration in the leaching solution was measured by ICP,and its redox potential was determined by pH meter.The leaching residue was characterized by XRD and SEM.The results show that both the two bacteria bioleaching processes are effective for very low-grade molybdenum tailings of 5%slurry concentration.The presence of bacteria is beneficial to leaching of molybdenum tailings.Sulfobacillus sibiricu has better leaching results of molybdenum tailings,and its molybdenum leaching rate is 18%after 23 dleaching while acidithiobacillus ferrooxidans has only 8% molybdenum leaching rate.

Study was made on the process for recovery of La and Ce rare earth metal elements from rare earth sulfate solution with sodium sulfate double salt method.The effects were investigated of reaction time,reaction temperature,sodium sulfate dosage and solution pH on rare earth recovery.The optimized technological conditions were obtained through single-factor condition experiments and orthogonal experiments as follows:reaction time of 120 s,reaction temperature of 65 ℃,sodium sulfate-rare earth mass ratio of 5.2∶1,and rare earth sulfate solution pH value of 2.0.Under the optimized conditions,the overall recovery of rare earth is more than 95%.The rare earth-sodium sulfate double salt is analyzed by XRD,and the result shows that high-purity lanthanide-sodium sulfate double salt was obtained.

During production of tantalum powder by sodium reduction of potassium tantalum fluoride,power consumption is reduced by adjusting heat preservation time for sodium reduction with agitation to reduce the energy consumption and cost.After the activation temperature of potassium tantalum fluoride is adjusted and the activation time is extended,the activating effect is improved and the metal impurity content is less than 10×10-6 in the metallurgical-grade tantalum powder from continuous production while the national standard is 30×10-6.Therefore,the produced tantalum powder reaches high-purity grade.

Germanium-containing polymetallic materials were pretreated progressively with hydrochloric acid-ammonium fluoride-potassium,and then separated by distillation using hydrochloric acid to extract germanium tetrachloride.The final recovery of germanium is about 95.20%.The dosages were systematically studied through experiments of pretreatment hydrochloric acid,ammonium fluoride,potassium permanganate and distillation hydrochloric acid,and then optimum process conditions were determined.Compared with the conventional hydrometallurgical process of sulfuric acid leaching-tannin precipitation-germanium concentrate-hydrochloric acid distillation for germanium extraction,the recovery of germanium in the above process is improved by about 21%.

Resource distribution characteristics of complex rare metal associated ore are introduced.The main methods of separation and extraction of complex rare metal associated ore and their advantages and disadvantages are summarized.It is pointed out that the beneficiation-metallurgy combined process is an important way to realize comprehensive utilization of these resources.

Chemical and physical properties and phase characteristics of red mud are introduced.The latest development and existing problems are reviewed of valuable metal extraction,such as Fe,Al,Ti and RE elements from red mud at home and abroad.And also development trend of effectively extract valuable metals from red mud is pointed out.

时光荏苒,岁月如歌,历经六十载的砥砺磨练,长沙有色冶金设计研究院有限公司迎来了甲子华诞。六十年前,新中国成立之初,国家一穷二白,百废待兴。国家"一五"计划发轫,加快工业化建设的步伐,要求重点发展中南各省、

Ni-Co-ZrO_2 composite coating was successfully fabricated on the substrate of Q235 steel by pulse electro-deposition of nickel sulfate(NiSO4·6H2O),cobalt sulfate(CoSO4·7H2O)and zirconia(ZrO_2)particles.Microstructure and chemical components of the composite coating were analyzed by SEM and EDS,respectively.Moreover,the corrosion resistance of Ni-Co-ZrO_2 composite coating was investigated.The results show that the coating has homogeneous and compact microstructure without defects such as pores and cracks at the interface with the substrate.ZrO_2 particles dispersed in Ni-Co alloy substrate,and the morphology of Ni-Co alloy grains changes from fibril-like shape to cauliflower-like shape with the addition of ZrO_2 particles.The thickness of the coating is about 60μm after 1.5hdeposition,and Ni-Co-ZrO_2 composite coating has crystalline microstructure in the coated state.With the content of ZrO_2 particles increasing and duty ratio decreasing in the coating,Ni-Co alloy grains are refined and the corrosion resistance of the composite coating is significantly improved.The best corrosion resistance is obtained when ZrO_2 content is 20g/L and duty ratio is 40%.

W-2%ZrO_2composite powder was prepared via azeotropic distillation using(NH4)6H2W12O40·xH2O and Zr(NO3)4·3H2O as the raw materials,and CH3CH2 OH and CH3CH2CH2CH2 OH as the dispersants.Phase,morphology and microstructure of the products obtained from different preparation stages were analyzed using XRD,SEM,EDS and TEM,respectively.The results show that the composite complex of WO3 · mH2 O and Zr(WO4)2·nH2O is produced due to the coprecipitation reaction between(NH4)6H2W12O40·xH2O and Zr(NO3)4·3H2O during azeotropic distillation.The composite complex has better dispersibility without hard aggregates than the precursor powder prepared by evaporation crystallization,and transforms into the mixed oxide power consisted of WO3 and m-ZrO_2 by 750℃calcination.After 750 ℃×2hreduction and then 800 ℃×2hreduction,the composite powder still has WO_2-coated ZrO_2 particles with oval wormlike shape and 10~15nm particle size.When the temperature in the second reduction stage is improved to 900 ℃,the mixed oxide power completely transforms into W-ZrO_2 composite powder of polyhedron spherical and square morphology.