Investigation of the kinetics of reduction of nickel tungstate by hydrogen |
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Authors: | S Sridhar D U Sichen S Seetharaman |
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Affiliation: | (1) Department of Materials Science and Engineering, Massachusetts Institute of Technology, 02139 Cambridge, MA;(2) Division of Theoretical Metallurgy, Department of Metallurgy, Royal Institute of Technology, S-100 44 Stockholm, Sweden |
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Abstract: | In the present work, the kinetics of reduction of nickel tungstate, NiWO4, by hydrogen was investigated by a thermogravimetric method in the temperature range 891 to 1141 K. The experiments were
conducted under both isothermal and nonisothermal conditions. The products were examined by X-ray diffraction analysis. The
results indicate that the reduction reaction proceeds in two steps; first, reduction of NiWO4 to nickel as well as WO2 and then WO2 to tungsten. From the isothermal experiments, the activation energies of the two reaction steps were calculated to be 95.3
± 4.9 and 80.8 ± 6.4 kJ · mol−1, respectively. The activation energy value obtained from nonisothermal experiments for the first step is in agreement with
the isothermal experiments. The values are compared with the activation energies reported in other literature for the individual
oxides.
Formerly with Royal Institute of Technology, Stockholm, Sweden |
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Keywords: | |
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