Kinetics of extracting magnesium by reduction of prefabricated pellets with silicon-calcium alloy powder under relative vacuum
(Key Laboratory of Ecological Metallurgy of Multimetal Intergrown Ores of Ministry of Education, School of Metallurgy, Northeastern University, Shenyang 110819, China)
Abstract: The extraction of magnesium by prefabricated pellets with CaSi2 as reductant was studied under relative vacuum. The morphologies, chemical compositions and phases of the reduction slag were analyzed using scanning electronic microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD), respectively. The results showed that a small amount of argon flow could greatly improve the reduction rate of MgO. The process of extracting magnesium from prefabricated pellets under relative vacuum could be well explained by Model F1. The process of reducing magnesium oxide by CaSi2 was a solid-liquid reaction. This process was controlled by chemical reaction, the temperature had a great influence on the reduction reaction, and the value of the apparent activation energy was 108.99 kJ/mol. The phase analysis of reduction slag showed that the content of MgO had an effect on the crystal transformation of Ca2SiO4.
Key words: isothermal kinetics; magnesium; calcium disilicide; flowing argon; silicothermic process