MOLDABLE REFRACTORY COMPOSITION AND PROCESS FOR PREPARING THE SAME

摘要

This moldable refractory composition is intended to be used in the production of cast refractory pieces resistant to molten metals, especially molten aluminum. It comprises 8 to 25% by weight of an aqueous phosphoric acid solution having a concentration of phosphoric acid ranging from 40 to 85% by weight, with up to 50% of the primary acidic function of the acid phosphoric acid neutralized by reaction with vermiculite. It also comprises from 75 to 92% by weight of a mixture containing wollastonite and an aqueous suspension containing from 20 to 40% by weight of colloidal silica. The weight ratio of the aqueous suspension to the wollastonite within the mixture ranges from 0.5 to 1.2. The composition according to the invention is particularly interesting in that it can be unmolded within a very short period of time that is less than 2 hours and can be as small as 10 minutes.