Stability properties of slurry based on coal-to-liquid gasification ash slag

Abstract

ABSTRACT The coal-to-liquid gasification ash and slag (GAS) is a solid waste with high yield, difficult degradation and environmental hazards. In this study, a novel extinguishing grouting material was made in the light of GAS, and carboxymethyl cellulose (CMC) was introduced as a dispersant for GAS slurry for easy blockage and bursting of pipes during the transportation of grouting material. Zeta-potential measurement, X-ray fluorescence and water separation experiment were utilized to discuss the mechanism and suspension stability of GAS slurry with different water-cement ratios and amount of CMC addition. The fire extinguishing material and the optimal mixing ratios were also obtained. The content of SiO2, Fe2O3, CaO and Al2O3 in GAS accounted for more than 80% of the total composition, and the main substances were gypsum, quartz and calcite. CMC had a prominent improvement effect on the suspension stability of slurry, and the more the added dosage, the stronger the suspension stability. The slurry suspension stability was maintained by steric hindrance and electrostatic repulsion; when the water-cement ratios were 1: 0.8, 1: 1.0 and 1:1.4, the optimal addition amounts of CMC were 1.5%, 1.25% and 0.75%, respectively.