Modification of clay raw materials to optimize slip casting

Abstract

The effect of surface-active substances (surfactants) on the state of water in clay was studied based on the data of swelling and sedimentation of clay particles in aqueous suspensions. The features of the influence of three types of additives-technical lignosulfonate and hyperplasticizers manufactured by Arkema and Movecreate are considered. When surfactant solutions are introduced into the clay system, an increase in the wettability of clay particles is observed, which promotes the adsorption of surfactant molecules on the surface of the dispersed phase, which depends on the structure of clay minerals and their impurities. Surfactants simultaneously have a plasticizing and structuring effect on the clay mass, leading to intensification of drying in the initial stages and, consequently, to a decrease in shrinkage deformations. The most effective additive is lignosulfonate, the introduction of which in an amount of 0.01 % in a clay suspension increases the fluidity of the suspension, and the mobility of water decreases by more than 3 times than in the presence of hyperplasticizers. The best preservation of the suspension is also ensured in the presence of a plasticizer-lignosulfonate. The main difference in the action of polycarboxylates and lignosulfonate is to change the sedimentation rate of clay suspensions. Modification of clay loam by surfactants leads to improved drying properties, quantified in a decrease in sensitivity to drying.