USE OF SiO2 OBTAINED FROM RICE HUSK IN THE SYNTHESIS OF CALCIUM SILICATES

Abstract

The rice husk is an agroindustrial waste which is produced in large amounts where rice industry is established. The ash of rice husk can be used as a source of silicon to produce calcium silicates. These compounds are used to make bricks of lime and sand. In the cement industry, as filler material in paint and polymers industry and also to produce dielectric porcelain.

Recently, the calcium silicates have been used to manufacture bioactive glasses. In this work, the controlled precipitation method was used to synthesize calcium silicates. The best conditions of synthesis were determined to obtain compounds with a certain composition and distribution of particle size. Moreover, It was analyzed the different physical-chemical phenomena that occur during the synthesis processes. Besides, It was studied the effects on certain conditions of the process such as precursors concentrations, nature of precipitant and temperature effect on the crystalline phases obtained at the end of the process. The evolution of crystalline phases during the thermical treatment was studied with X-ray diffraction (XRD). Other techniques of characterization used were the thermical analyses (DTA/TG) to know the evolution of the powers on thermical treatment and transmission electronic microscopy (TEM), to determine the morphology and the size of the synthesized particles.