The lining plate of the rod mill often adopts waveform, step shape or wedge shape. Manufacturers with good lining quality: Zhangjiagang Hengxinda, Luoyang Tiancheng, etc. According to different ore discharge methods, rod mills can be divided into central discharge type (overflow type) and peripheral discharge type (open type). The former is widely used, while the latter has ceased manufacturing. The following diagram shows the structure of an overflow type rod mill. As can be seen from the figure, the diameter of the hollow shaft neck at the discharge end is much larger than that of the overflow type ball mill of the same specification, which is to reduce the level of slurry and accelerate the speed of slurry passing through the rod mill. The discharge port of a large rod mill can reach 1200mm.