Fabrication of calcium phosphate glass using eggshell and its crystallization behavior

Abstract

The thermal properties and crystallization behavior of calcium phosphate glass fabricated using eggshell were examined. Nature eggshell has several impurities in the main component of CaCO3. To manufacture calcium phosphate glass, washed eggshell was dissolved in aqua-regia while adding a solution of isopropyl alcohol, D. I. water and phosphoric acid. The calcined precursor was melted at 1000°C, and the glass (Tg : 540°C) was crystallized at 620~640°C, which temperature range is relatively low compared to the crystallization temperature of other general types of calcium phosphate glass. The calcium phosphate glass using eggshell was successfully crystallized without any additional nucleating agents due to the multiple effects of impurities such as Fe2O3, Al2O3, SrO and SiO2 in the eggshell. The main crystalline phase was β-Ca(PO3)2 and a biocompatible material, hydroxyapatite, was also observed. The crystallization process was completed under the condition of a holding time of only 1 h at the low temperature.