Let us consider another calculation of grinding balls assortment for the initial loading of a clinker ball mill. We have obtained all necessary data through the online service on our website. Note that this customer is not a resident of Ukraine and it was not possible to source the specifics of customer’s production.
The customer specializes in cement production.
The production parameters are as follows:
- The inner drum of the ball mill is divided into two chambers.
- The lining of the first chamber is steel slabs with elevators. The lining of the second chamber is rubber slabs of the type «wave».
- Dry grinding method.
- Grinding material is a mixture of limestone (chalk, marble or other) in 75% and 25% clay.
- The size of the material is 13-15mm.
- Grinding requirement: residue on a sieve (size of 80μn) is not more than 7%.
Since cement production material is sufficiently abrasive, it is necessary to use grinding balls with increased hardness. We have refined the material parameters of the armour platingin the first chamber and recommended to our client to use the balls with the volume hardness of at least 60 HRC. The coefficient of grinding for the mill is 22-25 per cent of the internal volume.
The calculation of the average balls diameter in each chamber showed that the following assortment of grinding balls should be used to maximize grinding:
— In the first chamber: 90mm — 3 tons, 80mm — 2 tons, 70mm — 500kg, 60mm — 500kg. Average diameter is 82.5mm. Current loading should be of 90mm ball;
— In the second chamber: 40mm — 1 ton, 30mm — 1 ton, 25mm — 4 tons. Thus, the average diameter in the chamber is 28 mm, therefore the ball of 30mm must be refilled.
We supply the specified grinding balls to the customer. Energosteel specialists will remotely monitor the loading of grinding balls and the start of the mill. We will present the results of this test in the next publications.