Degradation Kinetics of Automotive Shredder Residue and Waste Automotive Glass for SiC Synthesis: An Energy-Efficient Approach

Generally, fossil carbon materials (coal, coke/char, and petroleum coke), biological carbon materials (charcoal, woodchips), and quartz from the earth's crust are sources of carbon and silica to synthesise silicon carbide (SiC) at temperatures between 2000 and 2200 degrees C. The study investigated the isothermal and non-isothermal kinetics of synthesising SiC from automotive shredder residues (ASR) and windshield glass of end-of-life-vehicle (ELVs) at 1300 degrees C, 1400 degrees C, and 1500 degrees C for 30 min. The kinetics of ASR and waste glass degradation were studied by relating the thermogravimetric data via the Coats-Redfern model. The reaction mechanism includes the rapid formation of a gaseous SiO intermediate, and carbon reduction of the SiO to SiC is reaction-rate-controlling. The understanding of kinetics inferred that the optimisation of SiC formation is entirely associated with the conversion of SiO2 to SiO vapour and their reaction with CO and carbon particles. The kinetic parameters of the degradation of mixed ASR and waste glass were determined, and the activation energy of mixed ASR and glass for non-isothermal conditions are 22.48 kJ mol 1, 2.97 kJ mol 1, and 6.5 kJ mol 1, and for the isothermal study to produce SiC is 225.9 kJ mol 1, respectively. The results confirmed that this facile way of synthesising SiC would conserve about 50% of chemical energy compared to the traditional way of producing SiC. A beneficial route of transforming the heterogenous ASR and glass wastes into SiC with economic and environmental benefits is recognised.

Automated summary

This study investigates the synthesis of silicon carbide (SiC) using automotive shredder residues (ASR) and glass wastes as raw materials. The results show that the reaction mechanism involves the rapid formation of a gaseous SiO intermediate and the reaction-rate-controlling carbon reduction of SiO to SiC. By optimizing the reaction conditions, about 50% of chemical energy can be saved compared to traditional SiC production, offering economic and environmental benefits by converting ASR and glass waste into SiC.