Thermal properties of technogenic hydrated magnesia material

Dumps of caustic magnesite dust are of interest as raw materials for the manufacture of medium-cement finegrained refractory concrete. This article presents the results of synchronous thermal analysis of this technogenic raw material and studies of the resulting burnt materials. It was found that after firing, 37‒41 % of the mass of the material is lost, the amount of periclase sharply increases ― from 2.5‒5.0 to 87.6 wt. %. There is a large difference in the textural and structural structure of most grains. During synchronous thermal analysis, 7 stages of mass loss were established: up to 450 °C they are associated with the removal of water, from 470 and up to 820 °C with the dissociation of carbonates. At a heating rate of 10 °C/min and a grain size of less than 0.071 mm, complete dehydration and decarbonization ends at 820.6 °C. Thermal regeneration of technogenic hydrated magnesia material by heating to 830 °C and above converts it into the initial active nanopericlase. Such a fired material will correspond to a finely dispersed periclase-calcareous refractory.