Dispersing (Deflocculating) Aluminas

The rheological properties of aqueous suspensions of a reactive alumina and high-alumina cements have been studied, and a method for evaluating the thinning effect due to agents used to deflocculate ceramic casting systems has been developed; a classification of thinning agents is proposed. Alumina dispersants make it possible to decrease the moisture content of Al₂O₃ suspensions by 50 – 60 rel.% and increase their volume concentration from 0.50 to 0.65. The characteristics of dispersing aluminas used for the thinning (deflocculation) of new refractory castables containing Al₂O₃ (76 – 96%) and organic deflocculants are given. Suspensions based on four types of dispersants (with a moisture content of 19 – 25%) exhibiting a thixotropic flow behavior are considered.