| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low-cost, high-strength and highly water-resistant gypsum board with the use ofαhemihydrate gypsum. SOLUTION: After dryingαhemihydrate gypsum as a byproduct produced in manufacturing phosphoric acid by a wet phosphoric acid manufacturing method, first alkali is added and then theαhemihydrate gypsum of a slurry form A is applied to one of the faces of a base paper for a lower cardboard. Further, the coated face is turned upward to be molded into a box shape with an open top. In addition, theαhemihydrate gypsum slurry B is poured into the interior of the box shape and theαhemihydrate gypsum slurry A is applied to one of the faces of the base paper for the upper cardboard, then the coated face is turned downward and is deposited on the coated face of the base paper for the lower cardboard to be cured and dried. Thus it is possible to obtain the low-cost, high-strength and highly water-resistant gypsum board. |
