| 摘要 |
A spinel containing slip-casting composition, a method for preparing the spinel slip-casting composition and a method for casting the slip into usable forms are described. The spinel employed to prepare the castable slips is a pre-calcined spinel prepared in the manner of copending application Ser. No. 184,189, filed Sept. 4, 1980, which is ball-milled with water, then mixed with a deflocculant at pH 9 or below and optionally with a molding aid. The slurry or "slip" is cast into a mold porous to water until the desired thickness of solid has been obtained and the excess "slip" decanted or otherwise withdrawn from the mold i.e., drain cast method or the "slip" is solid cast and dried to produce a green solid casting. The green shape is retained in the mold until it gains green strength, 1 hour to 5 days, and thereafter placed in an oven wherein it is fired to above about 1400 DEG C. for from 1 to 20 hours until it has reached its maximum density of between about 55 and 99 percent of theoretical. Also disclosed are mixtures of pre-fired spinels with calcined spinels of various heat histories to yield more durable green forms. In addition there is disclosed slips prepared from mixtures of different spinel compositions.
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