NiO reduction by Mg plus C combined reducer at high heating rates

The mechanism and kinetics of nickel oxide reduction by Mg + C combined reducer at non-isothermal conditions in a wide range of high heating rates (100-1200 degrees C min(-1)) were studied by high-speed temperature scanner technique. It was shown that both the magnesiothermal and magnesiocarbothermal reduction processes, unlike low heating rates (5-20 degrees C min(-1), DTA/DTG method), start beyond the melting point of magnesium and proceed via solid + liquid scheme. It was found out that the utilization of Mg + C combined reducer allows to significantly lower the reduction temperature (by about 200-400 degrees C) of nickel oxide as compared with exclusively magnesium or carbon reducers evidencing on the synergetic effect of combined reducers in the ternary mixture. The effective values of activation energy (E-a) for the NiO + Mg and 2NiO + Mg + C reactions were determined to be 185 +/- 15 kJ mol(-1)and 195 +/- 15 kJ mol(-1), respectively. Graphic abstract

Automated summary

The mechanism and kinetics of nickel oxide reduction by Mg + C combined reducer at non-isothermal conditions were studied at high heating rates. The utilization of the combined reducer showed a significant reduction in the reduction temperature of nickel oxide and exhibited a synergetic effect in the ternary mixture. Activation energy values for the reactions were determined to be 185 +/- 15 kJ mol(-1) and 195 +/- 15 kJ mol(-1).