| 摘要 |
1. A process for producing spherical, non-porous hydroxyapatite particles having a size which does not exceed 250 microns, and having a density of at least 3.00 g/cc, comprising: agglomerating in the presence of water as the only additive a hydroxyapatite powder feedstock having a purity of at least 97% and having metallic impurities which do not exceed 500 ppm, to form hydroxyapatite particles having a size which does not exceed 350 microns; drying said hydroxyapatite particles; and sintering said hydroxyapatite particles at a temperature of from about 1,100 degree C to about 1,200 degree C to provide spherical, non-porous hydroxyapatite particles having a size which does not exceed 250 microns and having a density of at least 3.00 g/cc. 2. The process of claim 1 wherein said hydroxyapatite powder has a purity of at least about 98%. 3. The process of claim 1 wherein said hydroxyapatite powder has metallic impurities which do not exceed 350 ppm. 4. The process of claim 3 wherein said hydroxyapatite powder has metallic impurities which do not exceed 300 ppm. 5. The process of claim 1 wherein said spherical non-porous hydroxyapatite particles have a size of from about 75 microns to about 125 microns. 6. The process of claim 1 wherein said spherical hydroxyapatite particles are sintered at a temperature of about 1200 degree C. 7. The process of claim 1 wherein said hydroxyapatite powder feedstock, prior to agglomeration, has an average particle size under 25 microns. 8. The process of claim 1 wherein said spherical non-porous hydroxyapatite particles have a density of at least 3.02 g/cc. 9. Hydroxyapatite particles produced according to the process of claim 1. 10. A process for producing spherical, non-porous hydroxyapatite particles having a size which does not exceed 250 microns, and having a density of at least 3.00 g/cc, comprising: reacting calcium hydroxide having a purity of at least 95%, and having metallic impurities which do not exceed 500 ppm, with phosphoric acid, in the absence of dispersants or surfactants, to provide a hydroxyapatite powder feedstock having a purity of at least 97% and having metallic impurities which do not exceed 500 ppm; agglomerating said hydroxyapatite feedstock in the presence of water as the only additive to form hydroxyapatite particles having a size which does not exceed 350 microns; drying said hydroxyapatite particles; and sintering said hydroxyapatite at a temperature of from about 1,100 degree C to about 1,200 degree C to provide spherical, non-porous hydroxyapatite particles having a size which does not exceed 250 microns and having a density of at least 3.00 g/cc. |
