Synthesis of nanocrystalline wollastonite powders by citrate-nitrate gel combustion method

Wollastonite was synthesized for the first time by a citrate-nitrate gel combustion method using citric acid as a reductant/fuel and nitrate as an oxidant. The yielding powders calcined at 650 degrees C for 2 h were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N-2 adsorption measurements (BET). The XRD data revealed that the resultant product was a pure phase of wollastonite without any other impurities. The SEM and BET results showed that the product was highly porous with a relatively high specific surface area of 40.69 m(2) g(-1). The average grain size calculated from BET measurements of calcining powders is found to be 50.7 nm. (C) 2008 Elsevier B.V. All rights reserved.