Synthesis of high temperature TES materials from silicates wastes for application in solar tower power plants

Abstract

Four Moroccan local industrial wastes were identified as potential high temperature (up to 1000 °C) thermal energy storage (TES) materials for application in solar tower power plants. These wastes are namely induction furnace slag (IFS) from the metallurgical industry, and three solid wastes from the coal-fired power plant industry (i.e. coal fly ashes (CFA), coal bottom ashes (CBA), and coal bottom clinker (CBC)). In the present paper, these wastes would be used as raw materials to develop/synthesize novel low-cost high-temperature TES materials for the same application. The main motive of this work is to manufacture enhanced versions of the selected wastes in order to eliminate their main points of weakness, i.e.: (1) their glassy form which restricts their structural strengths, (2) transform the wastes in the form of powder into solid crystalline materials with improved TES properties, and in the desired regular shapes. To fulfill this aim, a summary of the results of the different conducted characterizations on the four raw materials is presented. Then, the used synthesis method is described from the preparation of the raw materials formulations to the obtained final products. Finally, a laboratory experimental investigation was conducted on these obtained materials in order to assess their potential for TES application up to 1000 °C. Thus, their structural and thermophysical properties were evaluated, as well as their thermal stability up to 1000 °C. The obtained results suggest that most of the synthesized materials are good candidate materials for high-temperature thermal energy storage application (up to 1000 °C).