| 摘要 |
PURPOSE:To permit quick collapse of a casting mold by incorporating calcium carbonate into a molding material selectively contg. one kind of refractory particles, gypsum and binder and immersing the casting mold into an aq. soln. of an acid and/or ammonium chloride after casting thereby removing the casting material. CONSTITUTION:5-95wt% Calcium carbonate is incorporated into the molding material and the refractory particles consist of one kind selected from silica sand, magnesia, alumina, zirconia, etc. The binder consists of sodium silicate, Kibushi clay, bentonite, water glass, etc. or the mixture composed thereof. One kind of any of sulfuric acid, hydrochloric acid and nitric acid is selected for the acid and the initial concn. thereof is specified to >=1N. The initial concn. of the ammonium chloride is specified to >=5wt%. The content. of the acid or ammonium chloride to be incorporated into the aq. soln. is made >=30% of the equiv. of the calcium carbonate. Castings having intricate shapes and castings having small cores are easily produced by such casting mold. The casting mold is more inexpensive and the possibility of environmental pollution is decreased.
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