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Summary A study was made of the preparation of vanadium sesquisulfide by the technique of sulfidizing metallic vanadium powder with hydrogen sulfide. The stability of vanadium sesquisulfide in various media and its oxidation resistance were investigated.Translated from Poroshkovaya Metallurgiya, No, 2 (50), pp. 6–7, February, 1967. 相似文献
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M. P. Savyak I. V. Uvarova L. D. Konchakovskaya 《Powder Metallurgy and Metal Ceramics》1995,34(5-6):272-275
We have studied the kinetic characteristics of reduction of nickel and molybdenum from their oxide mixtures. We have monitored the development of the specific surface area during reduction. We calculate the nucleation rate and the apparent activation energy. The reduction temperature for molybdenum in the presence of nickel was shown to decrease appreciably; and unlike the conventional scheme, in which during the first reduction stage MoO3 transforms into MoO2 or molybdenum suboxide, metallic molybdenum appears. Such reduction conditions made it possible to produce fine (Ssp=20 m2/g) powder of the nickel-based solid solution and pure molybdenum from the oxide mixtures precipitated from the salt solutions at 650°C.Institute of Materials Science, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 5/6, pp. 52–56, May–June, 1995. 相似文献
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The feasibility of reductive precipitation of molybdenum oxides for molybdenum recovery from hypochlorite leach solutions
has been investigated. Hydrogen gas at elevated temperature and pressure and hydrazine hydrate were used as reductants. The
results are interpreted in terms of the behavior of mixed valent molybdenum polyanions. 相似文献
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Serdar Aktas 《Hydrometallurgy》2010,104(1):106-111
The present work investigates a hydrometallurgical process for silver recovery from spent silver oxide button cells. The effects of acid concentration, reaction temperature, reaction time and shaking rate on the silver dissolution are investigated in detail. In addition, an investigation regarding the dissolution kinetics of silver is undertaken, and the activation energy is found to be 26 kJ/mol. Silver is selectively precipitated as silver chloride using potassium chloride solution, ensuring that other impurities remain in the solution. Silver chloride is subsequently reacted with metallic zinc powder in 1.0 M HCl to yield metallic silver of 99.99% purity. The process is proven to be easy, straightforward and environmentally friendly. 相似文献
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The reduction rate of Mo oxide in slag by iron-carbon melt under different stirring conditions, reaction temperatures and slag composition has been investigated. Results indicate that the reduction of Mo oxide is a fast reaction; both stirring and temperature have evident influence upon the reaction; while the initial concentration of Mo oxide and content of fluoride in slag have also some influence upon the reaction. The reduction of Mo oxide is an apparent first order reaction. At 1440–1500°C, the reduction rate of Mo oxide is mainly controlled by Mo transfer in slag, with its diffusion activation energy of 223 kJ/mol. At 1500–1590°C, the transfer of Mo in metal turns to be the main limiting step, with its diffusion activation energy of 81.5 kJ/mol. 相似文献
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一维氧化钼纳米材料具有优异的电学性能、电化学性能、场发射性能和气敏性能,在催化剂、传感器、平板显示器、智能窗、电池电极等领域显示了广阔的应用前景;其主要制备方法有水热法、气相沉积法和模板法.该文在综述了一维氧化钼纳米材料的制备方法、性能及应用的研究进展之后,指出了当前制备方法中存在的问题,并展望今后的研究重点是如何将一维氧化钼纳米材料应用于实际. 相似文献
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V. V. Skorokhod Yu. M. Solonin Yu. G. Privalov 《Powder Metallurgy and Metal Ceramics》1984,23(3):171-175
Conclusions At temperatures of 600°C and higher the mixed oxide (W0.5Mo0.5)O3 is reduced with the starting uniform distribution of tungsten and molybdenum being retained in the end product, which is due to a single mechanism being operative in the process. As a result, a virtually homogeneous alloy is formed. At 400–600°C the reduction of tungsten and molybdenum from the mixed oxide involves two different structural mechanisms, which brings about a regrouping of the metals, disturbs their uniform starting distribution, and hence lowers the degree of homogeneity of the end product.Translated from Poroshkovaya Metallurgiya, No. 3(255), pp. 1–7, March, 1984. 相似文献
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研究了应用X射线荧光光谱仪的微区分析功能测定钢中氧化物夹杂分量的方法。优化了电解提取氧化物夹杂及X射线荧光光谱测定其分量的条件,同时建立了分析方法。实验结果表明,试样在弱酸性电解液并控制电流密度为0.02~0.06 A/cm2的条件下进行电解效果较好,测得氧化物夹杂总量一致。实验确定用X射线荧光光谱仪微区测定氧化物夹杂分量的最少样品量为不少于3 mg。用本法测定样品中氧化物夹杂分量SiO2,Al2O3,CaO,MgO,MnO2,Fe2O3,TiO2,Cr2O3的准确度(σ)为0.096%~0.63%,相对标准偏差小于6%,检出限为0.003×10-6~0.025×10-6。 相似文献
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The role of nitric oxide (NO) in the cholinergic regulation of heart rate (HR) recovery from an aspect of simulated exercise was investigated in atria isolated from guinea pig to test the hypothesis that NO may be involved in the cholinergic antagonism of the positive chronotropic response to adrenergic stimulation. Inhibition of NO synthesis with NG-monomethyl-L-arginine (L-NMMA, 100 micro M) significantly slowed the time course of the reduction in HR without affecting the magnitude of the response elicited by bath-applied ACh (100 nM) or vagal nerve stimulation (2 Hz). The half-times (t1/2) of responses were 3.99 +/- 0.41 s in control vs. 7. 49 +/- 0.68 s in L-NMMA (P < 0.05). This was dependent on prior adrenergic stimulation (norepinephrine, 1 micro M). The effect of L-NMMA was reversed by L-arginine (1 mM; t1/2 4.62 +/- 0.39 s). The calcium-channel antagonist nifedipine (0.2 micro M) also slowed the kinetics of the reduction in HR caused by vagal nerve stimulation. However, the t1/2 for the reduction in HR with antagonists (2 mM Cs+ and 1 micro M ZD-7288) of the hyperpolarization-activated current were significantly faster compared with control. There was no additional effect of L-NMMA or L-NMMA+L-arginine on vagal stimulation in groups treated with nifedipine, Cs+, or ZD-7288. We conclude that NO contributes to the cholinergic antagonism of the positive cardiac chronotropic effects of adrenergic stimulation by accelerating the HR response to vagal stimulation. This may involve an interplay between two pacemaking currents (L-type calcium channel current and hyperpolarization-activated current). Whether NO modulates the vagal control of HR recovery from actual exercise remains to be determined. 相似文献
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以煤油作为辉钼矿的主要捕收剂,以气溶胶形式进行加药,进行了煤油用量实验、浮选时间实验、pH值和磨矿细度影响实验,研究采用气溶胶浮选技术提高某铜钼矿钼回收率.气溶胶浮选技术可使铜钼混合浮选阶段钼回收率提高3%,且浮选时间缩短20%左右;在相同的回收率下,气溶胶浮选法使用的煤油用量可节省40%;气溶胶浮选的最佳磨矿细度为0.074mm占65%,浮选矿浆最佳pH值为9.与传统浮选工艺相比,气溶胶浮选技术具有浮选效率高、药剂用量少等特点,在低品位难选矿石浮选方面具有一定优势. 相似文献
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The liquid extraction of rhenium(VII) and molybdenum(VI) ions from sulfuric, hydrochloric, and nitric acid media is studied in the temperature range from 20 to 40°C using trialkylphosphine oxide in kerosene as an extracting agent. The maximum separation of these metals is attained when they are extracted from solutions of 1.0–2.0 M H2SO4 (the duration of intense phase mixing was 3–5 min). The enthalpy of the studied process is estimated to be ΔH = ?32.32 kJ/mol for molybdenum and ?51.52 kJ/mol for rhenium. The chemical aspects of the extraction process studied are discussed. 相似文献