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Title: Investigation of the kinetics of reduction of nickel tungstate by hydrogen

Abstract

In the present work, the kinetics of reduction of nickel tungstate, NiWO[sub 4], by hydrogen was investigated by a thermogravimetric method in the temperature range 891 to 1,141 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 NiWO[sub 4] to nickel as well as WO[sub 2] and then WO[sub 2] 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 [center dot] mol[sup [minus]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.

Authors:
 [1]; ;  [2]
  1. Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering
  2. Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy
Publication Date:
OSTI Identifier:
7199329
Resource Type:
Journal Article
Journal Name:
Metallurgical Transactions, B (Process Metallurgy); (United States)
Additional Journal Information:
Journal Volume: 25:3; Journal ID: ISSN 0360-2141
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; NICKEL ALLOYS; FABRICATION; NICKEL TUNGSTATES; REDUCTION; CHEMICAL REACTION KINETICS; THERMAL GRAVIMETRIC ANALYSIS; TUNGSTEN OXIDES; TURBOJET ENGINES; ALLOYS; CHALCOGENIDES; CHEMICAL ANALYSIS; CHEMICAL REACTIONS; ENGINES; EQUIPMENT; GRAVIMETRIC ANALYSIS; HEAT ENGINES; INTERNAL COMBUSTION ENGINES; KINETICS; MACHINERY; NICKEL COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; QUANTITATIVE CHEMICAL ANALYSIS; REACTION KINETICS; REFRACTORY METAL COMPOUNDS; THERMAL ANALYSIS; TRANSITION ELEMENT COMPOUNDS; TUNGSTATES; TUNGSTEN COMPOUNDS; TURBOMACHINERY; 360101* - Metals & Alloys- Preparation & Fabrication

Citation Formats

Sridhar, S, Sichen, Du, and Seetharaman, S. Investigation of the kinetics of reduction of nickel tungstate by hydrogen. United States: N. p., 1994. Web. doi:10.1007/BF02663389.
Sridhar, S, Sichen, Du, & Seetharaman, S. Investigation of the kinetics of reduction of nickel tungstate by hydrogen. United States. https://doi.org/10.1007/BF02663389
Sridhar, S, Sichen, Du, and Seetharaman, S. 1994. "Investigation of the kinetics of reduction of nickel tungstate by hydrogen". United States. https://doi.org/10.1007/BF02663389.
@article{osti_7199329,
title = {Investigation of the kinetics of reduction of nickel tungstate by hydrogen},
author = {Sridhar, S and Sichen, Du and Seetharaman, S},
abstractNote = {In the present work, the kinetics of reduction of nickel tungstate, NiWO[sub 4], by hydrogen was investigated by a thermogravimetric method in the temperature range 891 to 1,141 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 NiWO[sub 4] to nickel as well as WO[sub 2] and then WO[sub 2] 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 [center dot] mol[sup [minus]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.},
doi = {10.1007/BF02663389},
url = {https://www.osti.gov/biblio/7199329}, journal = {Metallurgical Transactions, B (Process Metallurgy); (United States)},
issn = {0360-2141},
number = ,
volume = 25:3,
place = {United States},
year = {Wed Jun 01 00:00:00 EDT 1994},
month = {Wed Jun 01 00:00:00 EDT 1994}
}