Acid Deashing Kinetics and Alkali Activation of Carbon Rich Particles in Coal Gasification Fine Slag to Prepare Capacitor Carbon

Abstract

Coal gasification fine slag (CGFS), a byproduct of coal and gasification agent interactions at high temperatures, presents significant challenges for the coal chemical industry. CGFS mainly comprises SiO2, Al2O3, CaO, Fe2O3 and carbon. Among them, the acid leaching of metal ions can produce the mesoporous structure in CGFS. The mesoporous structures not only provide channels for the embedding of potassium vapor and the overflow of CO2 and other gases during KOH activation, but also provide channels for the transport of electrolyte ions. Therefore, Studying the acid leaching process and elemental leaching of CGFS is highly significant. In this paper, the dissolution kinetics and mechanism of elements in CGFS during acid leaching were studied using carbon-rich particles (CRP) in CGFS as raw materials, and the conditions for acid leaching were optimized. Results from BET and chemical tests indicated that the mesoporous structure formation via acid leaching was a first-order kinetic reaction under the optimum conditions. Subsequently, the process parameters of alkali deashing and KOH activation were optimized. The resulting activated carbon, CRP-AC-90, exhibited a surface area of 1409.93 m2/g, high specific capacitance and excellent cycling stability, showcasing CGFS’s potential in supercapacitor applications, providing a novel method for effectively utilizing CGFS.