Micronization of Magnesium Acetate by the Supercritical Antisolvent Process as a Precursor for the Production of Magnesium Oxide and Magnesium Hydride

Abstract

Magnesium acetate was micronized by the supercritical antisolvent (SAS) process. By SAS processing, submicrometric magnesium acetate particles with particle sizes ranging from 300 to 700 nm with a regular spherical morphology and an amorphous crystalline structure were obtained. In comparison, mechanically milled particles showed similar mean particle sizes but had an irregular morphology and a bimodal particle size distribution. By calcination, SAS-processed magnesium acetate was converted into magnesium oxide, preserving the morphology of particles. By hydrogenation, the acetate was converted into magnesium hydride, a solid-state hydrogen storage metal hydride. The rate of release of hydrogen by thermolysis of magnesium hydride was enhanced by the particle size reduction, and there was a direct relationship between the size achieved by SAS micronization of the magnesium acetate precursor and the rate of release of hydrogen from the hydride.