| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of the conventional crushing system using an air-swept vertical crusher that porous coarse powder having low specific gravity is not crushed into particles having a desired particle size and a part of the coarse powder is mixed in a product as it is to deteriorate the quality of the product when a raw material in which fine powder is intermingled with the coarse powder is crushed by the conventional crushing system. SOLUTION: The raw material in which fine powder is intermingled with porous coarse powder having low specific gravity is compacted and granulated into particles having the desired particle size by a granulator and the granulated particles are thrown in the air-swept vertical crusher and crushed. When this granulation step is adopted, pores in the coarse powder are squashed beforehand and consequently the density of the coarse powder can be made higher. As a result, only the particles having the desired particle size pass through a separator so that the coarse powder is hardly mixed in the product. COPYRIGHT: (C)2005,JPO&NCIPI
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