WET-PROCESS FOR PRODUCING ALPHA-TYPE CALCIUM TRIPHOSPHATE CEMENT

摘要

PURPOSE:To obtain a cement easily curable by hydration, having high uniformity and giving a cured product having high compressive strength by reacting a suspension of calcium hydroxide with an aqueous solution of phosphoric acid at a specific temperature and a specific final concentration of the reaction product and calcining the product. CONSTITUTION:A calcium phosphate cement is produced by wet-process comprising the reaction of a suspension of calcium hydroxide and an aqueous solution of phosphoric acid and the calcination of the resultant precipitate of calcium phosphate. The process is carried out as follows. A suspension of calcium hydroxide is made to react with an aqueous solution of phosphoric acid at 50-100 deg.C under a condition to give a final reaction product concentration of 5-25%. The obtained mixture of hydroxyapatite and calcium diphosphate is calcined to obtain the objective alpha-type calcium triphosphate cement. The cement gives a hydrated and cured product having extremely high compressive strength exceeding that of a dry-process cement obtained by the re-calcination under pressure.