CaC2 Production from Pulverized Coke and CaO at Low Temperatures—Reaction Mechanisms

Abstract

CaC2 production with pulverized feeds was proven viable at temperatures about 400 °C lower than that required by the current electric arc technology (2100–2200 °C), which led to development of an autothermal process. For the purpose of reactor design, the reaction mechanism of coke (C) with CaO at temperatures up to 1750 °C is studied in a thermogravimetric analyzer (TGA) coupled with a mass spectrometer (MS). Results indicate that the reaction of C with CaO generally proceeds in three stages, starting at 1460 °C for CaC2 formation, followed by reaction of CaC2 with CaO and by decomposition of CaC2. The second stage is observable only at the complete consumption of C while the third is controlled by surface evaporation of Ca. Reaction behavior at the surface of coke and CaO particles is proposed, including the three-stage reactions and the role of CaC2–CaO eutectics, that promotes CaO diffusion and CaC2 production.