The traditional roller arm sealing system and mill return material sealing system of HRM4800 raw meal vertical roller mill suffer from poor sealing and air leakage issues. These deficiencies lead to reduced internal mill air temperature, increased load on the circulation fan and kiln tail fan, higher specific power consumption for raw meal grinding, elevated oxygen content in kiln stack flue gas, and increased denitrification costs. To address these challenges, an optimized retrofit solution was implemented: the roller arm sealing system was upgraded to a new combined structure of "labyrinth seal + multi-bellows flexible connection", with the multi-bellows flexible connection fabricated from high-molecular wear-resistant polyurethane material to ensure sealing conformity and durability. Simultaneously, the gravity-weighted flap air lock valve at the mill return material inlet was retrofitted with a fully enclosed vibratory feeder, achieving complete airtightness throughout the material conveying process. After the retrofit, system air leakage was effectively controlled, and the on-site working environment was significantly improved. Operational data shows that the average oxygen content in kiln stack flue gas decreased by 0.57%, the specific power consumption for raw meal grinding dropped by 0.2kW·h/t, the average operating power of the kiln tail fan decreased by 95kW, annual carbon emissions were reduced by approximately 1 777t, and annual comprehensive economic benefits reached 2.533 2 million  CNY, demonstrating outstanding energy-saving, consumption-reducing, and environmental protection performance.