Wet ball mills are important pieces of equipment in mineral processing, handling a wide range of materials such as quartz, iron ore, copper ore, and gold ore. Over time, the cylinder and liners of a wet ball mill will experience wear and tear, affecting its efficiency. This article introduces the use and installation methods of wet ball mill liners.

Use and Maintenance of Wet Ball Mill Liners

Wet ball mill liners are divided into rubber liners and high-manganese steel liners. The size of the liner must consider factors such as ease of handling, loading and unloading, and access to and from the mill. In recent years, the size of ball mill liners has been standardized. The service life of rubber liners is 2-4 times longer than that of high-manganese steel liners. Of course, the difference in service life is significant depending on the grinding method and conditions. In a single-stage grinding mill, the service life of rubber liners is typically only 0.5 times longer than that of high-manganese steel liners. In a two-stage grinding mill, the service life of rubber liners is generally 2-3 times longer than that of high-manganese steel liners.

Installation Methods for Wet Ball Mills

1. Installation Method of Rubber Liners at the Feed End

The original feed end liner consisted of 18 high-manganese steel liners. After replacement with rubber liners, the number of liners is reduced to 9. Previously, the liners were directly fixed with bolts; now, the rubber liners are fixed with rubber strips. The dimensions of the rubber liners and rubber strips are determined according to customer requirements.

2. Installation Method of Rubber Liners at the Discharge End

The original discharge end liner included 12 outer ring grid plates, 12 inner ring grid plates, 12 outer ring liners, 12 inner ring liners, and 2 middle plates. After replacement with rubber liners, the number of inner and outer ring grid plates and middle plates remains unchanged, but the name is changed to discharge chute. The inner and outer ring rubber grid plates and the rubber middle plate are fixed by rubber strips. The dimensions of the rubber grid plates and rubber strips are determined according to customer requirements.

Years of practice have proven that replacing ZGMn13 liners with rubber liners at the inlet and outlet ends has yielded significant benefits. Firstly, it simplifies installation, reduces difficulty, and increases installation speed, allowing for faster start-up and maintaining mill volume without affecting its overall capacity. Secondly, it extends service life by more than double compared to ZGMn13 liners, saving material costs and reducing the frequency of liner replacements.

Years of practice have also demonstrated the significant effectiveness of replacing single-hole liners with double-hole bolted high-manganese steel liners for wet ball mill cylinders. Double-hole bolted liners are better able to withstand the impact of steel balls inside the mill, providing a more secure fit and reducing bolt breakage. This avoids frequent bolt breakage and reduces the need for liner replacements. Therefore, it improves the ball mill’s operating rate and ensures normal production operation.

Precautions for Ball Mill Liner Replacement

1. Before installing the liners, thoroughly clean the inside of the mill cylinder of dust and dirt. When installing the liners, apply a layer of 1:2 cement mortar between the inner wall of the mill cylinder and the liner, and tighten the liner bolts while the mortar is still wet. Smooth the gaps between the liners with sand and mortar.

2. Before installing the liners, inspect and repair them. The back and sides should be smooth and flat. Thoroughly clean the bolt holes of sand and remove any casting flash to ensure the bolts can be easily inserted.

3. Carefully place sealing gaskets on the bolts securing the liners to prevent leakage of slurry.

4. For directional liners, ensure the direction is correct. Long mills are generally divided into two chambers by partition plates. The feed end is the first chamber, which uses stepped liners. During installation, the thinner end of the stepped liner should be aligned with the arrow direction of the mill’s rotation. The grate holes of the diaphragm plate are conical; during installation, the larger end of the cone should be aligned with the discharge direction of the ball mill. The cylinder liner plates must not form annular gaps.

5. When installing the diaphragm plate, all bolts should be inserted, and then tightened gradually in three stages. Note that the bolts connecting to the inner disc of the cylinder should be tightened first, followed by the bolts on the cylinder body. After all bolts are tightened, the nuts of the bolts on the inner disc of the cylinder should be spot-welded to prevent loosening.

6. Feeding and trial operation can only begin after the cement mortar has solidified to the required strength. Any loose bolts discovered during operation must be tightened immediately.