Investigation of the kinetics of reduction of nickel tungstate by hydrogen
- Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering
- Royal Inst. of Tech., Stockholm (Sweden). Dept. of Metallurgy
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.
- OSTI ID:
- 7199329
- Journal Information:
- Metallurgical Transactions, B (Process Metallurgy); (United States), Vol. 25:3; ISSN 0360-2141
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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