Method for the Simultaneous production of Calcium Carbonate and Calcium Citrate from Eggshells.

Abstract

The invention discloses a method for the simultaneous production of calcium carbonate and calcium citrate from eggshells. The process begins with the cleaning of eggshells using hot water at 50-90°C to remove organic residues and impurities. The cleaned eggshells are then subjected to alkaline deproteinization with a sodium hydroxide (NaOH) solution at 2-10% concentration, heated to 60-80°C, to remove proteins and organic materials. The resulting calcium carbonate is reacted with a citric acid solution at 10-50% concentration, heated to 60-90°C, while maintaining a pH of 3.5 to 4, to produce calcium citrate and precipitate additional calcium carbonate. The mixture is filtered to separate the calcium citrate, which is then precipitated, washed, dried, and ground into a fine powder. This method offers an efficient, sustainable approach to utilizing eggshells, optimizing resource use, reducing waste, and providing valuable calcium products for various industrial applications.