| 摘要 |
<p>1,227,133. Fluidized bed granulation. STRUTHERS SCIENTIFIC & INTERNATIONAL CORP. 4 April, 1968 [18 April, 1967], No. 17761/67. Heading B5A. [Also in Division C1] Fertilizer granules are produced by spraying a slurry of fertilizer material on to a fluidized bed of growing granules, heated to 180-220‹ F. and fluidized by air, separating fines from the effluent air and returning them to the bed, and withdrawing product granules from the bottom of the bed. The product granules may be screened: fines are returned to the bed, oversize are ground and recycled for screening, and those of required size are cooled to 120‹ F. by fluidizing with cool air. The exhaust air is further heated, and used in the granulating stage. The slurry may be of (NH 4 ) 2 HPO 4 , produced by reacting H 3 PO 4 with NH 3 gas to form NH 4 H 2 PO 4 which is reacted with further NH 3 , or of triple superphosphate, produced by reacting ground phosphate rock with 40% H 3 PO 4 at 200-230‹ F.</p> |
