In this paper, the wasted quartz and coal waste fines were made into carbon–silicon composite agglomerates. The effect of particle size for raw material, moisture content, molding pressure, and curing time on the strength and reactivity of carbon–silicon composites agglomerates at high temperature were studied. From the experimental results, it can be seen that the proper molding pressure, moisture, curing time, and the smaller particle size of the raw material can significantly increase agglomerates strength. For the raw material with particle size of 75 μm, the moisture content is 8 wt%, the molding pressure is 320 MPa, the cold strength of the agglomerate can be 30.7 MPa, and the hot strength is 12.6 MPa with crushing strength rate and the powdering rate of 97.02% and 0.52%, respectively. It is observed that the strength of the carbon–silicon composite agglomerate tends to be stabilized when the curing time reaches 30 days. The high-temperature reactivity study of carbon–silicon composite agglomerate shows that after the chemical reaction, the main component of the agglomerate is β-SiC. The adequate carbon type and carbon content will reduce the gas loss of SiO₂ from the agglomerate. It is possible that the reaction rate in the agglomerate is improved by using composite bonding.

Graphical Abstract