This paper describes the effect of the ratio of two starting materials, eggshell (ES, source of Ca) and rice husk (RH, source of silica) on the direct synthesis of wollastonite via a facile two-step solid state method, i.e. ball milling of the raw materials followed by calcination of the mixture at 1,000 ^oC. The investigation was focused on optimizing the ratio of ES and RH to maximize the formation of wollastonite. Keeping the wt.% of RH constant, four different ratios of RH and ES (10:2.6, 10:3.0, 10:3.3 and 10:3.7) were used and the observed result revealed that the initial ratio of RH and ES plays a key role in controlling the formation of wollastonite as the major phase which was confirmed by x-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) techniques. The bioactive property of this wollastonite was studied in simulated body fluid at 37 ^oC while the time dependent growth of hydroxyapatite (HA) on the surface of wollastonite was examined by SEM and XRD. Observed data supported the bioactive nature of wollastonite as biomaterial.

Keywords: Wollastonite, Eggshell, Apatite, Bioactive