Effects of manufacturing conditions on physical properties of integrated gasification combined cycle (IGCC) slag geopolymer

Abstract

In this study, we used integrated gasification combined cycle (IGCC) fused slag, a by-product of IGCC, to analyze itsapplicability as a high-strength geopolymer in terms of particle size, alkaline activator concentration, and solid-liquid ratio. We also examined its stability. A planetary ball mill was employed to pulverize the slag for 4, 6, and 8 h so as to adjust theparticle size to a desired value. The results showed that the compressive strength of the geopolymer made of the 6 h pulverizedmaterial and 12 M alkaline activator was the highest (29.8 MPa). In the case of the 8h pulverized material, the compressivestrength of the geopolymer got weaker. Therefore, it was found that an optimal particle size was necessary for strengthdevelopment. When the IGCC fused slag was finely pulverized (average particle size = 128 µm, the strength increased with anincrease in the molar concentration. At 18 M, the maximum strength was 59.908 MPa. A heavy metal dissolution test wasperformed. The specimen’s heavy metal dissolution was detected to be lower than the reference value. Hence, the specimenwas found to be safe. Therefore, if IGCC fused slag with an optimum particle size is used the resulting geopolymer can beapplied as a construction material.