INFLUENCE OF SODIUM HYDROXIDE ON THE PROPERTIES OF FOAMED GEOPOLYMERS BASED ON SOLID FUEL ENERGY WASTE

Development of new methods for utilization of ash and slag waste and waste heap rock will improve the ecological and economic situation. It is promising to obtain foamed geopolymer materials based on these wastes. Geopolymers are new inorganic three-dimensional aluminosilicate polymers obtained by alkaline activation of aluminosilicate raw materials. The content of hydroxides in the reaction system is a very important parameter in the development of geopolymers. Varying their content significantly changes the degree of polymerization of dissolved substances in the reacting system, and also affects the intensity of foaming gas release. In this work, the optimal amount of sodium hydroxide was selected for the synthesis of foamed geopolymers based on ash and slag waste of the Novocherkassk State District Power Plant, ash and slag waste of the Lugansk Thermal Power Plant, waste heap rock of Mine No. 21 in Krasnodon and waste heap rock of the V.I. Lenin Mine in Novoshakhtinsk. The chemical and phase compositions of the selected solid fuel energy wastes were studied, the results of which indicate that these materials belong to aluminosilicates and can be used to obtain geopolymer materials. To study the effect of sodium hydroxide content on the properties of foamed geopolymer material, its content was selected from 0 to 7.5 wt. %. Optimum concentrations of sodium hydroxide were established, which ensure the effective production of foamed geopolymer materials from various solid fuel energy wastes. Studies have shown that the content of sodium hydroxide plays a key role in the formation of the structure and properties of geopolymers.