Application of Dry Grinding as an Optimisation Tool for the Surface Area Development in Geopolymer Cement Manufacture

Geopolymer materials have improved physical and chemical properties when adequately ground. A small hammer crusher was designed that crushes stones to produce very high surface areas required for optimised strength development in their dry state. The maximum feed size, moisture, blade clearances, blade numbers and blade speed were identified as key variables. Fineness of the output was measured for various crushing speeds and sieve sizes. Residues of the milled product were measured using a 90-micron sieve. The dry grinding method was found to be 45% more efficient than the wet method. It was also observed that it requires less energy that the wet process. Overall research findings indicate that it is economic for both small-scale and large-scale grinding for optimised particle size reduction of raw materials used in the manufacture of geopolymer cements.