The behavior of alkali accumulation of coke in the cohesive zone is confirmed, and the kalsilite crystals observed on the coke pore walls are presented in the hexagonal prism and sphere morphology. Closer to the lower edge of the cohesive zone, the amount of potassium adsorbed in coke decreases and the amount of sodium adsorbed increases. The content of K2O in cohesive zone coke ash is approximately 19-34 times that of feed coke, while the corresponding Na2O content is about 7-14 times that of feed coke.