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1.
STUDYONTREATMENTOFAMMONIALEACHINGSLAGINTHEMETALLURGICALPROCESSOFTUNGSTENSunPeimen;LiHonggui;LiYunjiao;LiuMaosheng;SuPengtuan(... 相似文献
2.
1 INTRODUCTIONWiththecontinualexploitationanddevelopmentoftungstenmaterials ,wolframitebecomeslessandless .Statisticaldatashowthattheproportionofwol framiteisonly32 .9%andthatofscheeliteis 4 5 .5 %intungstenresources ,therestisscheelite wolframitemixedconcentrateandmostofnewlyexploredtung stenisscheelite[1] .Therefore ,howtoeconomicallyexploitscheelitebecomessignificantlyimportantindevelopingtungstenindustriesinChina .Currently ,causticleachingisappliedtohandlewolframiteconcentrate ,andh… 相似文献
3.
CAUSTIC DECOMPOSITION OF SCHEELITE AND SCHEELITE-WOLFRAMITE CONCENTRATES THROUGH MECHANICAL ACTIVATION 总被引:3,自引:0,他引:3
CAUSTICDECOMPOSITIONOFSCHEELITEANDSCHEELITE-WOLFRAMITECONCENTRATESTHROUGHMECHANICALACTIVATIONLiHonggui;LiuMaosheng;SunPeimei;... 相似文献
4.
Li Yunjiao San Peimei Li HongguiSu Pengtuan Zhao Zhongwei Liu Maosheng 《中南工业大学学报(英文版)》1997,4(1):32-35
Evaporatingcrystallizationiswidelyusedtoprepareammoniurnparatungstate(APT)crystalfromindustrialammoniumtungstatesolution.Usually,anammoniumtungstatesolutionwithdensityof1'20--1.28g.cm--3(aboutWO,250--280g.l--l)isevaporatedinanenamelreactorat80--90Cfor6--8htocrystallizeoutarnmoniumparatungstatecrystalswithapparentdensityof1'0--1.4g.cm--3.Intherecentyears,manyusersathomeandabroadhavestrictqualityrequirmentnotonlyinchemicalcompositionbutalsoinphysicalproperties,includingparticle--sizeanddistrib… 相似文献
5.
Leaching of low-grade refractory tungsten ore was carried out through mechanical activation. The effect of temperature, amount
of Na2CO3, addition of NaOH, ratio of liquid to solid and leaching time on the recovery of WO3 was studied. The WO3 recovery upto 96%–99% has been achieved when the tungsten ore was digested by soda not more than three times stiochiometric
amount at 185–195 °C for 1.0–2.0 h. The WO3 recovery can increase 10%–15% compared to that of conventional soda autoclave process.
Project supported by the Key Program of the 8th Five-year Plan of China
Synopsis of the first author Zhao Zhongwei, born in 1966, received Ph D degree in 1995. Major research field: hydrometallurgy, seperation science and
mechanochemistry. 相似文献
6.
WO3 nanowires were fabricated by a hydrothermal method, which proceeded at 170 °C for 48 h in a solution containing C2H10N6H2SO4 as a dispersant and Na2WO4 as a starting material. The nanowires exhibit a well crystallized one-dimensional structure with 20 nm in diameter and several microns in length. The physicochemical properties of WO3 were compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis spectroscopy (UV-Vis). The photoactivity of the as-perpared WO3 nanowires was evaluated through the photodegradation of methylene blue (MB) in aqueous solution. The experimental results demonstrate that addition of C2H10N6H2SO4 salt in the WO3 nanowires synthesis process can enhance its photocatalytic activity obviously. 相似文献
7.
Preparation of AgSnO2 composite powders by hydrothermal process 总被引:2,自引:0,他引:2
Silver-tin oxide powders were synthesized by the hydrothermal method with Ag(NH3)2^+ solution and Na2SnO3 solution as raw materials and Na2SO3 as reductant. The precipitation conditions of Na2SnO3 solution and the reduction conditions of Ag(NH3)2^+ were also investigated. The powders prepared were characterized by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and energy spectrum analysis, The results show that pH value of the solution is a key parameter in the formation of Sn(OH)4 precipitate and the reduction reaction of Ag(NH3)2^+ can release H^+ ions, which results in synchronous precipitation of Sn(OH)6^2- as Sn(OH)4. The reduction of Ag(NH3)2^+ and precipitation of Na2SnO3 occur simultaneously and the coprecipitation of silver and tin oxide is reached by the hydrothermal method. The silver-tin oxide composite powders have mainly flake shape of about 0.3 μm in thickness and there exists homogeneous distribution of tin oxide and silver in the powder synthesized. 相似文献
8.
Pt-WO3 nanoparticles uniformly dispersed on Vulcan XC-72R carbon black were prepared by an ethylene glycol method.The morphology,composition,nanostructure,electrochemical characteristics and electrocatalytic activity were characterized,and the formation mechanism was investigated.The average particle size was 2.3 nm,the same as that of Pt/C catalyst.The W/Pt atomic ratio was 1/20,much lower than the design of 1/3.The deposition of WO3·xH2O nanoparticles on Vulcan XC-72R carbon black was found to be very difficult by TEM.From XPS and XRD,the Pt nanoparticles were formed in the colloidal solution of Na2WO4,the EG insoluble Na2WO4 resulted in the decreased relative crystallinity and increased crystalline lattice constant compared with those of Pt/C catalyst and,subsequently,the higher specific electrocatalytic activity as determined by CV.The Pt-mass and Pt-electrochemically-active-specific-surface-area based anodic peak current densities for ethanol oxidation were 422.2 mA·mg-1Pt and 0.43 mA·cm-2Pt,1.2 and 1.1 times higher than those of Pt/C catalyst,respectively. 相似文献
9.
The dissolution kinetics of malachite was investigated in ammonia/ammonium sulphate solution. The effects of ammonia and ammonium
sulphate concentration, pH, leaching time, reaction temperature, and particle size were determined. The results show that
the optimum leaching conditions for malachite ore with a copper extraction more than 96.8% are ammonia/ammonium concentration
3.0 mol/L NH4OH + 1.5 mol/L (NH4)2SO4, liquid-to-solid ratio 25:1 mL/g, leaching time 120 min, stirring speed 500 r/min, reaction temperature 25 °C and particle
size finer than 0.045 mm. The dissolution process of malachite with an activation energy of 26.75 kJ/mol is controlled by
the interface transfer and diffusion across the product layer. A semi-empirical rate equation is obtained to describe the
leaching process and the reaction orders with respect to concentration of ammonia and ammonium sulphate are 2.983 0 and 0.941
1, respectively. 相似文献
10.
Preparation and characteristic research of anhydrous magnesium chloride with dehydrated ammonium carnallite 总被引:1,自引:0,他引:1
Taking the saline lake bischofite and NH4Cl that was removed with the ammonia method and continuously followed by filtration as raw materials with a molar ratio of 1 : 1 of MgCl2 to NH4Cl, ammonium carnallite was synthesized. And then the ammonium carnallite was dehydrated to some extent at 160 ℃ for 4 h. Ammonium carnallite reacted with ammonia at 240 ℃ for 150 min and the ammonation ammonium carnallite was produced. Finally, the ammonation ammonium carnallite was calcined at 750 ℃ into anhydrous magnesium chloride containing only 0.1% (mass fraction) of MgO. On the other hand, dehydrated ammonium carnallite was mixed with the solid ammonium chloride at mass ratio 1 : 4 at high temperature and with the differential pressure of NH3 above 30.5 kPa. The dehydrated ammonium carnallite of mixture was dehydrated at 410 ℃, and then calcined at 700 ℃ into anhydrous magnesium chloride with only 0. 087% (mass fraction) of MgO. X-ray diffraction and electron microscopy analysis results prove that anhydrous magnesium chloride obtained by both methods hasn't mixed phases,the particle is large and even has good dispersion, which is suitable for preparation of metal magnesium in the electrolysis. 相似文献
11.
A new technology was developed to recover multiple valuable elements from the spent Al2O3-based catalyst by X-ray phase analysis and exploratory experiments. The experimental results show that in the condition of roasting temperature of 750 ℃ and roasting time of 30 min, molar ratio of Na2O to Al2O3 of 1.2, the leaching rates of alumina, vanadium and molybdenum in the spent catalyst are 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by precipitators A and B, and the precipitation rates of vanadium and molybdenum are 94. 8% and 92. 6%. Al(OH)3 was prepared from sodium aluminate solution in the carbonation decomposition process, and the purity of Al2O3 is 99. 9% after calcination, the recovery of alumina reaches 90. 6% in the whole process; the Ni-Co concentrate was leached by sulfuric acid, a nickel recovery of 98. 2% and cobalt recovery over 98.5% can be obtained under the experimental condition of 30% H2SO4, 80 ℃, reaction time 4 h, mass ratio of liquid to solid 8, stirring rate 800 r/min. 相似文献
12.
Optimization of efficient stable reagent of alkaline thiourea solution for gold leaching 总被引:1,自引:0,他引:1
1 INTRODUCTIONThiourea ,asanontoxic goldleachingreagentsubstitutingcyanide ,hasattractedtheinterestofmanyresearchersallovertheworldsincethedissolu tionofgoldinthioureasolutionwasfirstreportedin194 1,andaseriesofstudiesonthetheoryandtech nologyforleachinggoldbythioureahavebeencon ducted[1 3] .Mostreportson golddissolutioninthioureasolutionwereconcernedwithacidicmedia .Itwasdifficultforgoldtodissolveinalkalinesolutionbecauseofthepassivationofelementsulfurproducedbytheirreversibledecompositi… 相似文献
13.
模拟水中B30铜镍合金耐蚀性的电化学研究 总被引:1,自引:0,他引:1
当模拟水介质的pH在7~9之间,随着pH值的增大,B30铜镍合金的耐蚀性能增加;pH大于9时,B30铜镍合金的耐蚀性能又随pH的增大而降低.模拟水介质的温度升高,氯离子或硫离子浓度的增加,都会使B30铜镍合金的耐蚀性能降低.在模拟水中加入绿色水处理缓蚀剂复配聚天冬氨酸40 mg/L时,对B30铜镍合金具有明显的缓蚀效果. 相似文献
14.
Highly crystalline orthorhombic Bi2WO6 powders were hydrothermally synthesized from aqueous solutions of Na2WO4 · 2H2O and Bi (NO3)3 · 5H2O over a wide range of pH. The effect of pH on morphologies, sizes and properties of the Bi2WO6 crystals was investigated. The band gaps of the as-prepared Bi2WO6 were determined from the onset of the absorption edge of UV-vis diffuse reflectance spectra. The methyl orange photodegradation
was employed as a probe reaction to test the photocatalytic activity of the as-prepared samples under visible light irradiation.
The photocatalytic activities of methyl orange degradation under visible light irradiation are strongly dependent on the pH
used in the synthesis. The highest efficiency is observed at pH=7.
Funded by the PCSIRT, the National Natural Science Foundation of China (Nos. 50532030 and 50625206) and the Zhejiang Provincial
Natural Science Foundation of China (No. Z4080021) 相似文献
15.
YAG(Y3Al5O12) powder was prepared by co-precipitation method.To avoid pH values changing intensely during titration process,the 4 3 NH HCO solution with 4 3 NH NO was used as precipitant solution.The pH change of precipitant solution during titration process,compositions of precursor,phase formation process and morphology of the prepared powder were investigated by means of pH meter,FT-IR,XRD and TEM.The results show that the presence of 4 3 NH NO in 4 3 NH HCO solution is crucial to alleviate the pH change,lower the calcination temperature and meliorate the morphology of YAG powder.The mechanisms were studied in detail.The YAG phase can be obtained at a lower temperature of 900 ℃.The obtained powder,composed of elliptical particles,showed a meliorated morphology. 相似文献
16.
Uniform crystalline TiO2 thin films were coated on silica glass fibers by liquid phase deposition from aqueous solution of ammonium hexafluorotitanate at low temperature. TiO2 thin films and nanopowders were prepared by adding H3BO3 into (NH4)2TiF6 solution supersaturated with anatase nano-crystalline TiO2 at 40 ℃. The effects of the deposition conditions on the surface morphology, section morphology, thickness of the deposited TiO2 thin films were investigated. The results indicate that the growth rate and particle size of the thin films were controlled by both the deposition conditions and the amount of anatase nano-crystalline TiO2. 相似文献
17.
The separation of Co2+ from Zn2+, Cd2+ by anion-exchange chromatography was discussed. The chromatographic column containing anion resin 201 × 7 which was saturated
with a solution of ammonium chloride. The effects of the eluant acidity and eluant composition on the separation were investigated.
The results indicate that this anion-exchange chromatography is suitable to the separation of Co2+ from Zn2+, Cd2+, and the condition of separation is simple and convenient. When the column is saturated with NH4Cl solution (2.0 mol/L, pH=4.0), the separation can be completed effectively. Zn2+ and Cd2+ can also be separated when different eluants are used and the pure solution with high concentration of Zn2+, Cd2+ respectively can be obtained easily.
Biography of the first author: WANG Xin-yan, born in Dec. 1975, majoring in extraction chemistry. 相似文献
18.
The precursor of ammonium aluminum carbonate hydroxide was synthesized by using aluminum sulfate (Al2 (SO4)3 ) and ammonium carbonate((NH4 )2CO3 ). The effects of α-Al2 O3 seeds and mixture composed of α- Al2O3 and ammonium nitrate, as well as multiplex catalysts (AT) on phase transformation of alumina in sintering process were investigated respectively. The results show that the α-Al2 O3 seeds and the mixture of α-Al2 O3 and ammonium nitrate can lower the phase transformation temperature of α-Al2O3 to different extents while the particles obtained agglomerate heavily. AT has great potential synergistic effects on the phase transformation of alumina and reduces the phase transformation temperature of α-Al2O3 and the trends of necking-formation between particles. Therefore the dispersion of powder particles is improved significantly. 相似文献
19.
Synthesis of polycrystalline Yb:Gd3Ga5O12 nanopowders by homogeneous precipitation method 总被引:1,自引:0,他引:1
The Ytterbium doped gadolinium gallium garnet [Yb3+:Gd3Ga5O12, Yb:GGG] precursor powders were synthesized via homogeneous precipitation method using Yb2O3, Ga2O3, Gd2O3 and ammonium bicarbonate [NH4HCO3] as precipitator, and ammonium sulfate [(NH4)2SO4] as additive. The evolution of phase composition and micro-structure of the powders were characterized by — TG DTA, XRD,
IR, and TEM. The results indicate that all precursor powders completely transform to Yb:GGG phase by calcining at 900 °C for
8 h, the resultant powders are well dispersed and have smaller particle size approximately 80 nm owing to the electrostatic
effect. 相似文献
20.
Jianfeng Wu Jian Li Xiaohong Xu Lanfang Yang Jufang Wu Fang Zhao Chuanguo Li 《武汉理工大学学报(材料科学英文版)》2009,24(4):651-653
A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding
SiC ceramic foam as matrix and Na2SO4 as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results
indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs
between Na2SO4 and SiC matrix. Na2SO4 has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage
density and high thermal conductivity, it is suit for energy storage under high temperature.
Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418) 相似文献