This research was performed to stabilize heavy metals in mine tailing using fly ash and clay. Fly ash-clay-mine tailing system were investigated using XRD (X-ray diffractometer), XRF (X-ray fluorescence spectrometer), TG-DTA, SEM (Scanning Electron Microscope), Dilatometer and UTM with various mine tailing contents (~15 wt%). The fly ash used in this research was mainly composed of SiO2 (33.01 wt%), Al2O3 (28.54 wt%), K2O (3.32 wt%), Fe2O3 (1.47 wt%), CaO (9.97 wt%). SiO2 and Al2O3 composition of the clay was over 61 wt%. And the mine tailing have high composition of SiO2(26.91 wt%), CaO (24.25 wt%), Fe2O3 (22.97 wt%). Therefore, it was estimated that fly ash-clay-mine tailing have enough sintering characteristics. The shrinkage of specimens started at around 850oC and changed little up to 1100oC, but increased markedly at above 1100oC. The shrinkage rate is strongly related to the decarbonization amount of coal fly ash. As the result of SEM, structure of the specimens with mine tailing addition showed more close than the one without mine tailing.
Compressive strength of the specimens with mine tailing was highly increased to approximately 200~420 kgf/cm2, it satisfied the first grade criterion for clay brick by KS L 4201. The specification of leaching characteristics of the sintered specimens were within the Korean regulation standard.