Sol-Gel Synthesis of Calcium Silicate from Carbide Waste: Optimisation and Characterisation.

Calcium silicate (CaSiO3) has a wide range of important applications in industries such as ceramics, glass, and cement. However, the productions of CaSiO3 still largely relies on conventional raw materials, highlighting the need for more sustainable alternatives. This study aimed to synthesize calcium silicate from carbide waste using the sol-gel method and to investigate the effect of the CaCl2-to-Na­2SiO3 mol ratio and aging time on the resulting CaO content. The synthesized products were analyzed using the back titration method to determine the CaO content, while the optimum sample was characterized using SEM-EDX and XRD. Process optimization was performed using Response Surface Methodology (RSM). Back titration of the optimum sample showed a CaO content of 31.51%, while EDX showed an SiO2 content of 60.36%, consistent with commercial calcium silicate specifications. SEM analysis revealed an acicular crustal morphology. XRD characterization confirmed the formation of both ?-wollastonite and ?-wollastonite phases. The RSM optimization results indicated that the quartic model provided the best fit, with an adjusted R2 0.9358 and a predicted R2 of 0.7970, with a predicted CaO content of 31.543%. these findings demonstrate the potential of carbide waste as an alternative raw material for the more sustainable synthesis of calcium silicate. Contribution to Sustainable Development Goals (SDGs):SDG 9: Industry, Innovation, and InfrastructureSDG 12: Responsible Consumption and Production