Influence of Surfactants on the Moulding Properties of Ceramic Masses During Soft Moulding of Bricks

In recent years, soft-molded facing ceramic bricks, often referred to as hand-molded bricks, have become increasingly popular and in demand among consumers. The use of a variety of molding techniques and decorative methods allows for the production of bricks with a variety of aesthetically pleasing surface finishes. Soft-molded molding compounds exhibit increased deformation under load and penetration, reduced plastic strength, and critical compressive stress, which are achieved by increased water content, leading to increased air shrinkage and sensi-tivity to drying. Therefore, a pressing technological challenge in soft-molding bricks is to reduce the water content of ceramic compounds while maintaining the required rheological properties to achieve the desired brick surface finish. One way to achieve this is by incorporating surfactants into the raw material mixtures. For experiments based on a technical and economic analysis, we selected ionic surfactants, specifically technical sodium lignosulfonate (TSL). The experimental results showed that sodium lignosulfonate is an effective additive. Its addition to ceramic bodies at levels of up to 0.6% reduces water content, reduces stickiness, increases plasticity, and improves molding properties. SLS is particularly effective in ceramic bodies with a relatively high concentration of thinners.