Author(s)

Hiroaki Onoda, Hironari Nakanishi

Department of Informatics and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.

Oyster shells have received attention for use as a calcium resource. For this study, calcium phosphate was prepared from phosphoric acid and oyster shells. The influences of the concentration of phosphoric acid and pH in the preparation conditions were studied from the yields of calcium phosphate and unreacted carbonate, and the Ca/P ratios in precipitates. The yield of calcium phosphate and carbonate was low in the preparation condition with 0.1 mol/l of phosphoric acid. The obtained precipitates were the mixture of calcium hydrogen phosphate dihydrate and the unreacted calcium carbonate. The reactivity of the oyster shells with phosphoric acid was discussed from the yields and Ca/P ratios in precipitates.

Calcium Phosphate; Oyster Shells; Calcium Carbonate; Yield; Powder Properties

H. Onoda and H. Nakanishi, "Preparation of Calcium Phosphate with Oyster Shells," Natural Resources, Vol. 3 No. 2, 2012, pp. 71-74. doi: 10.4236/nr.2012.32011.