A low-cost and high-value reinforcing filler for styrene butadiene rubber fabricated by a pneumatic separation technique from coal gasification fine slag

A novel filler for rubber was prepared by deep processing of coal gasification fine slag (CGFS) using an airflow sorter. Five processed CGFS samples with different sizes and carbon contents were obtained. The effects of particle size, unburned carbon, and surface properties of CGFS on the comprehensive properties of filled styrene butadiene rubber (SBR) were investigated. The mechanical properties were improved with decreasing CGFS size, and the curing and mechanical properties exhibited better performance owing to the unburned carbon. Unburned carbon can improve the dispersion properties of the filler and the compatibility between the matrix and filler. The best values for the curing characteristics and mechanical properties of SBR appeared when CGFS-S2 and CGFS-S3 were used as the fillers, respectively. Heavy calcium carbonate (CaCO3) particles were used as a comparative filler, and the results demonstrated that CGFS particles have the potential to replace CaCO3 in rubber. A novel method for preparing coal gasification fine slag (CGFS) samples utilized as a reinforcing filler for the SBR matrix through an efficient pneumatic separation technique has been demonstrated. The superior filler–rubber interfacial interaction can contribute to significant reinforcement in the comprehensive performances of composites by the addition of CGFS series fillers into the SBR matrix. CGFS particles have great potential for application in rubber composites, and a new strategy of using CGFS as fillers has been established.