METHOD OF MANUFACTURING GYPSUM POWDER OF RAW MATERIAL FOR GYPSUM MOLDED PRODUCT FROM GYPSUM BOARD WASTE

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of not requiring chemical treating because the raw material capable of manufacturing a highly strong molded product has been obtained by carrying out the chemical treatment up to now because only the molded products with weak strength has been contained in the case of manufacturing the molded products using gypsum obtained from gypsum board waste as a raw material.;SOLUTION: Fine structures are broken by applying high mechanical stress such as mechanical compression or fine pulverization by an impact pulverizer to dihydrate gypsum in the gypsum board waste and hemihydrate gypsum is obtained by firing the same. the gypsum having excellent slurry flowability even in a little quantity of mixed water can be obtained by applying the mechanical strength such that oil absorbing quantity of the powder after making the hemihydrate gypsum becomes 65 ml/100g and thereby, the molded products with high strength can be obtained. For obtaining such a result, in the case by the mechanical compression for example, surface pressure of 100 to 500 MPa or line pressure of 20 to 100 kN/cm may be applied to the waste gypsum.;COPYRIGHT: (C)2013,JPO&INPIT