| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high concn. and low viscosity aq. gypsum slurry easy to handle by wet-grinding coarse gypsum in the presence of calcium carbonate whose average particle diameter is below that of the coarse gypsum and a dispersant. SOLUTION: A mixture is prepd. by mixing 100 pts.wt. coarse gypsum having 5-100μm average particle diameter with 1-100 pts.wt., preferably 5-50 pts.wt,. calcium carbonate whose average particle diameter is below that of the coarse gypsum, 0.1-10 wt.%, preferably 0.5-5 wt.% (expressed in terms of solid) dispersant based on the total amt. of the coarse gypsum and calcium carbonate and water. The dispersant is, e.g. a (meth)acrylic acid polymer having a wt. average mol.wt. of 500-30,000, preferably 1,000-20,000. The mixture is wet-ground with a sand grinder to obtain the objective aq. gypsum slurry having >=50 wt.% solid concn., <=2,000 cps, preferably <=1,000 cps viscosity and <=5μm, preferably <=2μm average particle diameter.
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