The Influence of Spray Drying on the Dispersive and Physicochemical Properties of Magnesium Oxide

Abstract

Magnesium hydroxide was obtained in a precipitation reaction with the use of magnesium nitrate or magnesium sulphate and sodium hydroxide. The influence of the temperature of the process, the mode and rate of substrate supply, as well as the concentration and ratio of the substrates on the product's properties, were tested. The intermediate product Mg(OH)2 was subjected to drying by static and spray techniques followed by calcination to obtain magnesium oxide. To establish the effect of the synthesis conditions and drying techniques on the dispersive and physicochemical properties of the magnesium oxide obtained, this product was characterized using a number of experimental methods to obtain the bulk density, polydispersity index, and particle size distribution in the nano- and micrometric ranges. Moreover, the wettability profiles in water system were examined. For selected magnesium oxide samples the crystalline structure was determined by the WAXS method, and adsorptive properties (surface area, volume, and size of pores) as well as electrical properties (dielectric permittivity and electrical conductivity) were measured. Application of all the above-mentioned methods enabled a comprehensive characterization of the products and revealed a significant effect of spray drying on their properties, in particular on their dispersion and morphology.