On the Plasticity of Clay Mixtures with Bauxite Residue of the Bayer Process

Abstract

“Bauxite Residue” (BR) is the main waste of alumina-producing Bayer process. With the aim to use BR in the heavy clay industry, the plasticity of clay mixtures with BR was studied by the “High Pressure Annular Shear Cell” (HPASC) technique. The information obtained is cohesion and pressure dependence values that enable the determination of optimal conditions for extrusion. The results for 30wt% BR addition, substituting the clay mixture, demonstrate that the maximum cohesion is increased. Nevertheless, the water demand is increased for achieving the appropriate cohesion and pressure dependence levels for extrusion, a factor that imposes increased demand for drying. By shifting the particle size distribution towards a higher mean particle size, redesigning the clay mixture or by polymer addition, the rheological behaviour of the paste can be adjusted.