Preliminary organic binder removal from castings

Thermoplastic organic binders used in the production of ceramics by hot casting with a slip mass are partially removed before firing by heating the castings in a mould composed of ceramic powder or on a porous support. This preliminary partial removal reduces scrap during firing. Ways of removing the binder and upgrading the firing are used in order to increase the product yield. There is an optimum ratio between the amount of binder removal and the amount remaining; the usual method of removal, heat treatment on a bed of ceramic powder, has been found to be satisfactory. Preliminary binder removal kinetics for various materials on heat treatment with Sinoxal-49 powder were examined in industrial tests. These tests showed that rapid removal began above 70 C. The best results gave 23% removal into the powder. This process should accelerate firing and increase the yield of satisfactory components. 3 refs.