Study on the technology of preparation of the calcium citrate from oyster shells

The technology of preparation of the calcium citrate from oyster shells was studied using the yield of calcium citrate as index.Single factor experiments were adopted to explore the influence of hydrochloric acid amount and sodium carbonate amount on the yield of calcium carbonate and citric acid amount, water dosage and crystallization time on the yield of calcium citrate.The results showed that the yield of calcium citrate could reach 92.3% under the conditions of 1 g of oyster shell powder, 20 m L of hydrochloric acid with 1 mol/L and 1.5 g of sodium carbonate.Under this condition, the rate was 91.24% with1.5 g of citric acid reacting with calcium carbonate in 15 m L of water, crystallizing under 30 ℃ for 4 h. The process has high yield for calcium citrate prepared by oyster shells, can be applied in practice.