| 摘要 |
PURPOSE:To obtain the titled aggregate, having low liquid passage resistance as well as improved separation ability and useful as liquid chromatographic packings, etc., by spraying a slurry of needle-like, columnar or rice granular hydroxyapatite crystalline grains under specific condition. CONSTITUTION:For example, phosphoric acid is added to a liquid containing Ca(OH)2 suspended in water and reacted at ordinary temperature - 150 deg.C to give a slurry of needle-like, columnar or rice granular hydroxyapatite crystalline grains having 10-50nm maximum diameter of the minor axis and 50-500nm length of the major axis. The resultant slurry is then adjusted to 1-50wt% crystalline grain concentration, sprayed in an air stream at 150-300 deg.C (inlet temperature of a drying chamber in a spray dryer), as necessary, dried at 80-120 deg.C for 0.1-10hr and fired at 400-700 deg.C for 1-3hr to afford the titled secondary particles, having 10-100mu median (based on the area) thereof and containing secondary particles of size <=300mu in an amount of >=90% based on the whole. |
