Influences of novel surfactants on the physicochemical properties of sodium aluminate solution relevant to the aluminium hydroxide precipitation process

Abstract

The physicochemical properties of sodium aluminate solutions are modified by adding different surfactants, and the variations of the surface tension, viscosity as well as the conductivity are investigated in detail. The modification of the properties of the solution is correlated with the aluminium hydroxide precipitation process from the solution (Bayer process). The results indicate that the precipitation ratio, the crystal size, as well as the intensity of the Al(OH)₃ products can be enhanced after addition of certain types of surfactants. The chemical compositions of the surfactants are reported and it can be shown that novel types of surfactants prepared by mixing different, relatively cheaper components exhibit the potential to replace the more expensive recipés commercially available. These improvements to the precipitation process are interpreted as being due to modification of the properties of the sodium aluminate solution after addition of the surfactants.