Síntese e caracterização de fosfatos de cálcio a partir da casca de ovo de galinha

Abstract

Calcium phosphates are ceramic compounds employed nowadays in development of biomaterials used as bone substitutes in clinical orthopedic and odontologic areas. The aim of this work was explore chemical routes able to convert chicken eggshell, a rich material in CaCO3, in inorganic calcium phosphates, as beta tricalcium phosphate (β-Ca3(PO4)2) and hydroxyapatite (Ca10(PO4)6(OH) 2), materials used as bone substitutes. A preliminary thermodynamic analysis has shown which acids were viable to chemical attack in chicken eggshell. Inorganic salts produced from chemical acid attack, using HCl, HNO3 and H3PO4, were converted in calcium phosphates in a second reaction step. Materials produced were heated in electrical furnace over 2 h at 900 °C. X-ray diffraction analyses have shown the presence of a mixture of different calcium phosphates phases and the formation of β-Ca3(PO4)2 single phase from different chemical routes and synthesis procedures that have been adopted.