Abstract
A dry distillation method was used for testing carbonaceous materials to be added to molding sand. The method had an advantage that such components as tar, water, and residual, carbon could be fractionally distillated. The effective ratio of tar content to chemically combined water present in carbonaceous materials used ranged from 1 to 26. The effect of carbonaceous additives was considerably influenced by the presence of binder in sand. Therefore, it needed to change the content of the additive according as the variety of binder was changed. To improve the collapsibility of CO2 sand mold, it was preferred to employ the carbon rich additive which contained plenty of tar whose melting point being higher than 400°C so that it might produce residual carbon as much as possible.
