Extracting aluminum oxide from high-alumina coal fly ash are significant to make up for the inadequacy of bauxite resource in China. How to comprehensively utilize silica components in coal fly ash is a key technical question in industrialization for extracting of alumina from coal fly ash. Desilication of coal fly ash (CFA) and preparation of xonotlite were studied using the silica-rich solution from the CFA as silica source and calcium oxide as calcium source respectively. The CFA is from a power plant at Shizuishan city in Ningxia, China. Xonotlite was successfully prepared by a series processes including predesilication, hydro-thermal synthesis. The experimental results indicated that SiO2in the coal fly ash changed into NaSiO3after the coal fly ash was treated by desilication using NaOH solution. Hydrated calcium silicate was obtained from the reaction of the solutions produced by desilication and Ca (OH)2at the condition of Ca/Si (mol)=1, T=160°Cand t=1h. Xonotlite was synthesized by the hydrated calcium silicate using the hydrothermal temperature of 260°C for 2 hours. Keywords: Coal Fly Ash, Pre-desilication, alkali Hydrothermally-treated, Xonotlite nanofibres
Comprehensive Utilization of High Alumina Coal Fly Ash Under the Recyclable Economy Model