The breakage of rods in the rod mill is quite serious; what are the reasons?
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Rod breaks in mills are quite severe; hundreds of them per night is considered a low number. Raising the liner height didn’t yield significant results either; the speed of the 4*6 meter mill is 14.3
Broken rods usually occur because the steel rods come into direct contact with each other inside the grinder; therefore, operation at low load for extended periods increases the risk of rod breakage. Another factor is the type of coal – if its grindability coefficient is low, it is difficult to grind it into slurry, which also leads to an increase in rod breaks. This situation is often accompanied by poor quality of the coal slurry.
Since you put it that way, it seems the broken ones are all 75mm rods. When picking up the rods, try to collect both the thin rods and the broken ones. Do you use Shenye’s grinding machines? If that’s the case, you can consult Kaiyue Coal Chemicals. They also faced serious issues with broken rods in the past, and the solution was to replace those rods; it’s possible that the steel rods used were not suitable for such mills
We have encountered this situation here before as well: with a 4*6 meter mill running at a speed of 14.3, the breakage of rods was extremely severe, making it impossible to carry out production. The key aspects to consider are as follows: 1. Whether the length of the steel rod meets the requirements; 2. If the material or hardness of the steel rod is insufficient, it will break very easily.
How did you resolve it in the end? Could you share your experience?
The size of the steel rod must be well controlled; if it is too long, the rod is prone to breaking.
OP, what is the length of your steel rods? ? ? ?
They should be steel rods that have been lengthened, different from the original requirements
It is more likely that the technical parameters of the steel rod are not suitable for the operating conditions of the coal grinder
Another very likely reason is that the lifting height of the steel rod is too high, resulting in greater forces when it falls
This should not be a major issue; the height to which it can be raised is related to the structure of the liner and the speed of the mill. These parameters are generally fixed, unless the mill was manufactured by a company that does not specialize in rod mills. In most cases, brands such as CITIC QiuLin and ShenYe do not present any problems. It is likely that the steel rods used are hot-rolled round bars with a hardness of around HRC 20; it is recommended to use rods with a hardened hardness of HRC 45-55. I have served 70% of China’s coal chemical industry, and I am able to resolve issues related to broken rods.