This circulating fan is the core gas handling equipment in cement raw material grinding systems (such as air-swept mills and vertical roller mills). Its critical role is to drive the circulating flow of dust-laden hot gas (typically kiln exit gases) within the closed-loop system of grinding, drying, and classifying. Its primary functions include: providing the heat source for raw material drying, transporting ground material to the classifier for separation, and carrying the finished product meeting fineness requirements to the subsequent dust collection system. The fan operates continuously in a complex environment characterized by high dust concentration (up to 1000 g/Nm³), high humidity, medium temperature (~200°C), and abrasiveness.