Schwabe, Peter; Grunwald, Martin; Puppe, Lothar;

Casting investment compounds

The present invention relates to investment compounds containing zeolites and to models and moulds made from these. The investment compounds according to the invention are used in metal casting, preferably in the preparation of precision castings.

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We claim:

1. Casting phosphate-bonded investment compound powders, comprising, in addition to refractory materials and binders, zeolites in an amount of from 0.1 to 10% by total weight.

2. Casting phosphate-bonded investment compounds according to claim 1, wherein said zeolites are present in an amount of from 0.3 to 2.0% by total weight.

3. Casting phosphate-bonded investment compounds according to claim 1, wherein said zeolites are present in an amount of from 0.7 to 1.5% by total weight.

4. Casting phosphate-bonded investment compounds according to claim 1, wherein the zeolites represent one or more zeolites selected from the group consisting of faujasites, mordenites, zeolite .beta., zeolite .OMEGA., zeolite L, zeolite A, offretite, ZSM 12, pentasils, PSH-3, ZSM 22, ZSM 23, ZSM 48, EU-1, zeolite T, chabasites, gmelinites, ferrierites, zeolite rho and ZK-5.

5. Casting phosphate-bonded investment compounds according to claim 1 wherein said zeolite is one or more acidic types of faujasite structure.

6. Casting investment compounds according to claim 1 in the form of a powder mixture.

7. Casting investment compounds according to claim 1, in the form of a mixture obtained by dough-forming with a suitable aqueous or alcoholic mixing fluid.

8. Investment compound models, made from casting phosphate-bonded investment compounds according to claim 1.