Larnite Porous Granule Production using Eggshell

Abstract

In the current study, a biowaste, chicken eggshell, was used with commercial silica powder as a raw material resource for synthesizing porous bioceramic, larnite, granules with a solid-state reaction method. This study was carried out in two primary stages. In the first step, spherical structures were obtained using a facile spherical salt bead production technique developed by Jinnapat and Kennedy. Powdered chicken eggshells and commercial silica powder were used as the inorganic starting materials to produce the spherical structures. After the shaping procedure, it was determined that spherical granules with a broad range of granule sizes, ranging from less than 2 mm to the micrometer level, were achieved. Then, in the second step, a high-temperature heat treatment was carried out to produce porous larnite granules. Performed XRD analysis revealed that the phase purity of the larnite phase was achieved at the high-temperature heat treatment done at 1250°C for 2 hours. However, it was observed that after sintering, the size of the ceramic granules slightly increased, losing their general spherical shape by sticking to each other during the sintering process. Microstructure investigations of the larnite granules revealed a fine, homogenous microstructure with a bimodal porosity distribution. The coarse porosity between the fine larnite particle clusters was determined to reach up to 15-20 mm.