Overflow ball mill is also called overflow type ball mill. It is a kind of wet ball mill grinder, frequently used in the material refine grinding (finished material is lower than 0.2mm) or the second stage grinding. Overflow ball mills adopt the overflow principle to discharge the qualified material slurry higher than the discharge port naturally. Because the overflow ball mill is cylindrical, it can be divided into the short type and long type according to the cylinder length, but they have no difference in structure and working principle. Overflow ball mills feature high grinding precision, strong production capacity, and high comprehensive utilization rate, which can be widely used in the cement industry, silicate product industry, refractory material industry, fertilizer industry, black and non-ferrous metal mineral processing, etc.
The overflow ball mill is composed of cylinder, end cover, main bearing, quill shaft, transmission device, feeding device, manhole, pinion device, lining plate, etc.
Lining plates are laid inside the cylinder and end covers. There are 1-2 manholes on the cylinder for maintenance and replacement of the lining plate.
Overflow ball mill cylinder is welded by steel plate with a thickness of 15-36mm. Flange plates made of cast steel are welded at both ends of the cylinder.
When the ball mill rotates uniformly around the horizontal axis, raw materials enter the cylinder through the quill shaft from the feeding device and then rise to a certain height with steel balls under the combined action of centrifugal force and lining plate friction. After a while, they fall along the parabola under the action of self-weight and collide with each other to achieve the grinding purpose. Due to continuous feeding, the pressure causes materials in the cylinder to move from the feeding end to the discharging end. And the quill shaft diameter at the discharge end is slightly larger than that at the feed end so the material slurry in the mill has a certain inclination. When the height of the slurry surface is higher than the discharge port, they will overflow out of the mill. The quill shaft is equipped with reverse spiral blades, which can return the overflow steel balls and coarse material blocks to the ball mill.