Slag is transported into the factory by a loader, and then sent to the slag pile shed for storage and drying through the unloading hopper and belt conveyor. The stacked slag is picked up by a forklift, unloaded through a bar screen into the receiving hopper, and then evenly and quantitatively transported to the rubber belt conveyor through a metering belt conveyor. During the transportation process, the raw material undergoes multiple iron removal operations through an iron removal device, and is fed into the vertical mill for grinding by a screw conveyor and other air-locking feeding equipment. The slag entering the mill falls into the center of the grinding disc, and moves evenly to the edge of the grinding disc under the action of centrifugal force. It is crushed by the continuous rolling of the grinding roller and the material layer. The ground powder is selected and dried by the powder selector with the help of the hot air provided by the hot air furnace. The unqualified ore particles fall from the cone hopper back to the grinding disc for re-grinding, and the qualified ore powder is transported to the dust collector after leaving the mill with the air flow, and then enters the finished product warehouse for storage through the air conveying chute and elevator.