Porous magnesia compositions of a combined structure

In this research were developed heat-insulating magnesia compositions with technogenic fillers. A comparative analysis of the structures formed by different methods shows the high porosity of the compositions using a foaming agent, polystyrene pellets. Here was shown the expediency of obtaining porous compositions based on mixed magnesia binders with the addition of wastes of enrichment of skarn-magnetite ores (up to 30 %). The efficiency of the heat-shielding properties of materials is ensured by the creation of a highly porous combined structure by optimizing the formulation of the molding masses and by rational combination of various techniques of porosity. Effect of porosity methods on magnesia compositions structure was investigated. The conditions for formation of combined structures due to combination of cellular, granular and fibrous porosity were determined. Combined structures of various compositions based on technogenic fillers are characterized by porosity of 75 – 90%, density of 150 – 400 kg/m³ and coefficient of thermal conductivity of 0.04 – 0.08 W/(m °C). Methods for preparing molding mixtures have been developed based on the primary contact of the components forming the matrix stability and providing a stable highly porous structure of the compositions.It is revealed that the magnesian compositions are distinguished by increased technology, ensuring the greatest strength of the porous materials. (paper)