Self-hardening mold sand
AssigneeOnoda Cement Co., Ltd.
InventorsHiroshi Uchikawa, Hajime Kato
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Abstract
The specification discloses a self-hardening mold sand having surface stability and high compressive strength yet containing a comparatively small amount of water. The mold sand is prepared by mixing a self-hardening binder of clinker powder, containing 11CaO.7Al.sub.2 O.sub.3. CaX.sub.2 (where X is a halogen atom) and a sulphate, with a binder additive consisting of a surface active agent of which the main component is .beta.-naphthalene-sulphonic acid formaldehyde condensate salt, and then mixing this binder and binder additive with sand, water and preferably a retarder consisting of an organic carboxylic acid or boric acid.
Claims10
In a mold sand composition comprising a mixture of sand, water, a self-hardening binder and a surface active agent, the improvement comprising:
- from about 3 to about 6 percent by weight of water based on the sand;
- from about 2 to about 20% by weight of binder based on the sand, said self-hardening binder comprising a substantially anhydrite sulphate salt and clinker powder containing at least 2% calcium halo-aluminate of 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2, where X is a halogen atom;
- and the percentage of said surface active agent to sand is from about 0.02 to about 1.0% by weight, said surface active agent comprising b-naphthalene-sulphonic acid-formaldehyde condensate salt as its main component.
Dependencies are inferred from the claim text.