| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of increasing recovery yield of a gypsum content by highly precisely separating paper from waste material of a plasterboard thereby reducing remaining rate of cellulose, the method solving the following problem: when a waste plasterboard containing a relatively large amount of paper is used for a cement composition, the paper adversely affect fluidity and strength developing of mortar or concrete, which is undesirable, and therefore it is necessary to remove fiberized paper and to take the physical property and beauty of cement into consideration. SOLUTION: The method for recovering gypsum as a cement raw material from a waste plasterboard is characterized in that, after coarsely pulverizing the plasterboard and removing paper chips in a size of 30 mm or larger, the pulverized material is introduced to a stack of two or more dry sieves, in which opening sizes are sequentially decreased from the upper sieve to an opening size of 0.5 mm to 1.8 mm in the last sieve. COPYRIGHT: (C)2011,JPO&INPIT
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