Novel application of high temperature solution growth method in simultaneously preparing SiC/Ti3SiC2/TiC using photovoltaic Si waste and Ti-bearing blast furnace slag

Abstract

Photovoltaic silicon wastes (PVSWs) and Ti-bearing blast furnace slag (TBBFS) are typical new energy solid waste and traditional industrial solid waste respectively. The collaborative treatment of PVSW and TBBFS can realize the utilization of Si and Ti resources, as well as safeguard the ecosystems. Herein, an effective approach was proposed to prepare SiC, Ti3SiC2, and TiC using these two wastes as raw materials based on the innovative application of High Temperature Solution Growth Method (HTSGM). A Ti–Si alloy, which is rich in TiSi2 phase (stable) with a low melting point is synthesized from TBBFS through silicothermal reduction at a low operating temperature of HTSGM. Subsequently, the directional solidification process effectively optimized the segregation and carbon solubility of Ti–Si alloy, leading to the formation of TiC, Ti3SiC2, and SiC. The effect of directional solidification rate and the electromagnetic field is analyzed on in situ carburizing behavior and segregation of Ti–Si alloy, as well as controlled precipitation interval of the three carbides. Through the microcrystalline materialization treatment strategy of the associated waste slag, the entire process is devoid of solid waste or other pollution, achieving high-value and complete utilization of the two solid wastes. This work provides an innovative process for the green, clean, efficient, and high-quality collaborative treatment of PVSW and TBBFS.