COMPARISON OF OPTIMAL PROCESS MODES FOR PRODUCING WOLLASTONITE AND DIOPSIDE-CONTAINING FILLERS BASED ON RICE HUSK PROCESSING PRODUCTS

The use of wollastonite and diopside in various industries, including construction and bioengineering, is relevant today. Synthesis of these minerals from waste, such as rice husk, is not only an economically advantageous, but also an environmentally sustainable approach. Import substitution in the field of mineral fillers can significantly reduce dependence on foreign supplies and promote the development of domestic industry. The use of agricultural waste to obtain useful materials also corresponds to modern trends in the field of sustainable development and resource recycling. Comparative analysis of the processes of solid-phase synthesis of wollastonite and diopside can help in optimizing technologies and improving economic indicators. It is important to take into account not only the content of target minerals, but also the cost of energy, raw materials and processing time. Wollastonite and diopside containing fillers are successfully used for the production of polymer and building materials, and as a basis for bioceramics. Due to the predominant import of these minerals, their solid-phase synthesis based on silicon-containing derivatives of rice husk is promising. When synthesizing calcium silicate using limestone and silicon dioxide from rice husk, the content of β-wollastonite in the phase composition of the resulting product is significantly lower than in natural Mivall 30-97. Therefore, it is proposed to preliminarily obtain calcium oxide from limestone, which significantly increases the content of the acicular structure of the mineral in the product of the solid-phase reaction. In the case of obtaining calcium magnesium silicates, to ensure a high content of diopside in them, it is sufficient to heat treat rice husks at 5000C and interact with dolomite in the presence of boric acid as a flux. Thus, the optimal technological process of solid-phase synthesis of diopside-containing fillers is significantly simpler than wollastonite-containing ones, it is less labor-intensive, although it requires somewhat higher (by 2000C) temperatures. Comparative analysis of solid-phase synthesis processes of these minerals can reveal optimal conditions for their production, which in turn can lead to cost reduction and increased production efficiency.