Gilsonite is combined with coal and other ingredients as an additive in foundry sands to insure the quality of the molded part.
The lower gas evolution should reduce ventilation load on the pouring floor. The physical property relationships developed in new
mixes were confirmed by sand using Gilsonite as an additive.
Gilsonite is as a carbonate additive too and can be added to sands of foundry and play the role of a strong adhesive for them.
This reduces the downtime of casting operations. The most important uses of Gilsonite for foundry are as follows:
When the additive is combined with the clay, the nominal percentages by weight of the preened would be around 4% iron oxide, 4% Gilsonite and 16% metallurgical coke, the balance being essentially 70% to 75% clay and small amounts of other materials.
in the case of greater than normal amounts of smoke and/or emissions, the amount of the iron oxide can be increased in steps of 0.5% of the preened with a similar reduction in the metallurgical coke.
in the case of poor shakeout peel or casting surface problems the highly volatile carbonaceous material such as Gilsonite can be increased in 0.5% steps with a similar reduction in the clay portion of the preened.
the permissible ranges of constituents beyond which the additive would be less effective, expressed as a percentage by weight of the preened, are 2%-6% iron oxide, 6%-2% Gilsonite, and 12%-18% metallurgical coke.