| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of accurately separating paper from a gypsum board waste material and improving the recovery yield of gypsum components since it is not desirable that the flowability and strength development of mortar and concrete are adversely affected in the case of use in a cement composition when a relatively large amount of paper is contained. SOLUTION: The method is for recovering gypsum from a waste gypsum board as a cement raw material. After the gypsum board is coarsely crushed and the paper of 30 mm or more is removed, three or more stages of dry type sieves are provided. When the sieve of the third stage is the final stage among the continuous sieves of three stages, the sieve opening of the first stage is 2.5 mm or more, the sieve opening of the second stage is 0.5 mm to 1.58 mm, and the sieve opening of the third stage is a numerical value between the sieve openings of the first stage and the second stage. COPYRIGHT: (C)2011,JPO&INPIT
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