THE USE OF DEALUMINATED KAOLIN WASTE PRODUCED FROM ALUM INDUSTRY IN THE PREPARATION OF GEOPOLYMER BRICKS

Abstract

Dealuminated kaolin based geopolymer bricks were prepared through the reaction between sodium hydroxide as activator and the dealuminated kaolin waste produced from alum industry as a binder. The dealuminated kaolin waste was first dried, ground and characterized by XRF and XRD analyses then mixed with sodium hydroxide solution which was pre-prepared in different concentrations ranging from 2 to 14 mole.L-1. The dealuminated kaolin solid to sodium hydroxide solution mass ratio was about 0.7. In this thesis, the effect of using different concentrations of the sodium hydroxide (NaOH) solution through different curing times on the following properties of the final geopolymer brick are investigated: degree of geopolymerisation, water absorption, saturation coefficient, bulk density and compressive strength. The results also showed that the compressive strength approaches the minimum allowable value of strength of building bricks according to ASTM C62 (8.7 MPa) for 28 days under normal conditions starting from concentration approximately about 12M.