Synthesis of Calcium Fluoride from Discarded Egg Shell - A Potential Solid Lubricant

Abstract

Solid lubricant is an environment-friendly alternative to liquid lubricants, which can be applied in extreme environmental conditions like high temperature and pressure where liquid lubricants fail. In this work, an attempt was made to synthesize calcium fluoride, a solid lubricant material from scrap eggshell powder by using the ion exchange method. The prepared eggshell powder was treated with 40% concentric hydrofluoric acid and was manually mixed using a mortar and pestle. The synthesized CaF2 powder was characterized by using SEM and XRD. The degree of Crystallinity was calculated from the XRD data by using Origin Pro and Excel software. The Crystallinity of the prepared CaF2 powder was found to be 78.01%. The crystal size of the synthesized CaF2 powder was calculated using Scherer’s formula. The crystal size was found to be between 9–22 nm ranges. The synthesized calcium fluoride XRD intensity peaks were matching exactly with the JCPDS card of the standard CaF2 powder, confirming the presence of CaF2.