Thermal stability of a silica-rich vanadium tailing based geopolymer

With the rapid development of vanadium extraction from stone coal, large amounts of tailing were produced, which not only occupied vast land but also caused secondary environmental pollution. With the objective of comprehensive utilization of the secondary resources, the silica-rich vanadium tailing was converted into thermostable geopolymer. For geopolymer synthesis, the milled vanadium tailing was combined with fly ash and activated by sodium silicate. The geopolymer sample was heated at temperature of 150, 300, 450, 600, 750, 900 and 1050 degrees C, respectively. The milled vanadium tailing was obtained by dry ball milling of the raw vanadium tailing. Thermal stability of the geopolymer sample was evaluated in terms of the change of compressive strength and microstructure after heat treatment. Results showed that dry ball milling can effectively enhance the reactivity of the vanadium tailing. Compressive strength tests, SEM and FTIR analyses of the geopolymer sample before and after heat treatment indicated that its compressive strength increased at 900 degrees C. and apparent damage to its microstructure was not observed. These findings suggested that the vanadium tailing was potential for synthesizing fire-resistant geopolymer products. (C) 2012 Published by Elsevier Ltd.