Experimental Study on Solidification of Leachate Sludge with High Salt Content by Waste Incineration Bottom Slag

This paper takes the leachate sludge produced from the Guangzhou refuse landfill as the research object and selects sulfoaluminate cement as the fixation to solidify/stabilize the sludge. Meanwhile, bottom-slag is selected as the supplementary fixation. Through unconfined compressive strength test and Scanning electron microscope (SEM), the effect of the mixing amount of cement and bottom-slag on the sludge’s strength is systematically studied. Results show that sulfoaluminate cement can improve the strength of solidified sludge. Sulfoaluminate cement can increase the strength of samples by promoting the hydration reaction, but the effect is better when the content exceeds 40%. When the cement content is fixed, the strength of the sample increases with the bottom slag content. When the bottom slag content exceeds 10%, the proportion of cement in the hydration reaction will decrease, and then the strength of the sample will increase first and then decrease. In addition, under different cement contents, the sample will reach the peak value when the bottom slag content is 10%. Thus, 40% cement + 10% bottom slag is the relative optimal content.