Sustainable Mining and Metallurgy

Based on the principle of bulk solid waste utilization, the exploration test of mechanical-thermal-chemical composite activity stimulation of coal gangue was carried out. It is found that the original coal gangue has low activity after direct mechanical grinding due to the large amount of volatiles such as carbon, and cannot replace cement for concrete materials. The 28d compressive strength of the mortar sample prepared by thermal activation of coal gangue at 950℃ can reach 39.77MPa, and the activity index reaches 84.3%. Under the condition of adding 10% quicklime and roasting temperature of 950℃, the 28 d compressive strength of the mortar sample prepared by coal gangue reaches 43.07MPa, and the activity index reaches 87.8%. Under the condition of adding 7.5% industrial gypsum and roasting temperature of 950℃, the 28d compressive strength of the mortar sample prepared by coal gangue reaches 45.68MPa, and the activity index reaches 85.7%. When the roasting temperature is 950℃ and the additive ratio is 3.75% industrial gypsum and 3.75% quicklime, the 28d compressive strength value of the mortar sample prepared from coal gangue is relatively stable, and the activity index exceeds 100%, which can replace part of cement. From the perspective of energy saving and emission reduction, the suitable conditions for the stimulation of coal gangue are as follows: additive ratio 3.75% industrial gypsum +3.75% quicklime, roasting temperature 950℃, roasting time 30min.