Kinetic parameters of producing nickel metal powder under isothermal conditions
T.H. Nguyen Kinetic parameters of producing nickel metal powder under isothermal conditions / T.H. Nguyen, Nguyen Van Minh, Nguyen Thai Ha, Do Thanh Lich. — АлтГТУ: Ползуновский вестник, 2020 выпуск 4. — Барнаул. — 2020. — ISSN: 2072-8921. — С. 112-116. — Режим доступа: https://journal.altstu.ru/polz_vestnik/2020_1/70/article/209/THNguyen.pdf
The kinetic parameters of producing nickel metal powder, which is obtained through hydrogen reduc-tion from NiO micron powder under isothermal conditions were studied. The hydrogen reduction process of NiO micron powder under isothermal conditions was carried out in a tube furnace in the temperature range 275–316 ºC. The study of the crystal structure and composition of the powders was performed by XRD phase analysis. The specific surface area of the samples was measured using BET method with ad-sorption of nitrogen in low temperature. The average particle size of powders was determined via the measured specific surface area. The size characteristics and shape of the particles were investigated by scanning electron microscope. The calculation of the kinetic parameters of synthesizing process of nickel metal powder under isothermal conditions, was carried out using the Gray-Weddington model and Arrhe-nius equation. It was found that the rate constant of the reduction process at 316 ºC is approximately 2,6 times larger than in the case of reduction at 275 ºC, while the duration of the process was reduced by more than 2 times. The activation energy of hydrogen reduction process of NiO micron powder under iso-thermal conditions equal to ~ 48 kJ/mol, which indicates a mixed reaction mode. In this mode, increasing the temperature as well as eliminating the diffusion layer of the reduction product by intensive mixing are two rational ways to accelerate the process.