Acid deashing kinetics and alkali activation of carbon rich particles in coal gasification fine slag to prepare capacitor carbon

Coal gasification fine slag (CGFS) is a by-product of coal and gasification agent interactions at high temperatures, which presents significant challenges for the coal chemical industry. CGFS mainly comprises SiO 2 , Al 2 O 3 , CaO, Fe 2 O 3 , and carbon. Carbon-rich particles (CRP) in the CGFS contain large amounts of residual carbon and small amounts of metal compounds. Among them, the acid leaching of metal ions can produce the mesoporous structure in CRP. The mesoporous structures not only provide channels for the embedding of potassium vapor and the overflow of CO 2 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 CRP is highly significant. In this paper, the dissolution kinetics and mechanism of elements in CRP during acid leaching were studied and the acid leaching conditions were optimized using CRP as raw materials. 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 prepared activated carbon CRP-AC-90 has a surface area of 1409.93 m 2 /g, high-specific capacitance and excellent cycle stability, which shows the application potential of CRP in supercapacitors and provides a new method for effective utilization of CRP.