Some Methods to Improve the Working Efficiency of Ball Mill

The production efficiency of ball mill can be improved if the numbers of revolutions are increased appropriately, but we cannot over pursue more numbers of revolution. Some problems may occur because of the increase of revolution. For example, at present, ball mill is designed and manufactured according to the number of turns that less than theoretical critical number. There will be two problems if the machine rotates by using the critical or supercritical number of revolutions. One is that ball mill will lose the grinding function because of centrifugal force. The other one is that the mechanical vibration and the wear of components will be aggravated due to the high-speed rotating, so that the lifespan will be greatly reduced. At the same time, because the internal grinding function is destroyed, the discharge size will be coarsened, and the classification load will be increased, which will cause the finished products cannot meet the qualified granularity standard. In addition, the grinding media and liner wear will be increased.

Therefore, Most of those beneficiaton factories use the working number of turns rather than the critical in production.

At present, the most appropriate working revolutions is "n=(0.76-0.88)×n(critical turns) r/min".

Facts prove that when the filling rate of grinding media is 54%, and the rate of rotation is defined as the critical number of revolutions 88%, the grinding production efficiency is higher than that of 76%. For the fine grinding mineral (when the feeding size is less than 3mm and the ground products is below 0.1mm), it is obviously a bit of high if the rate of rotation is 88% of critical turns, which can influence the quality, so the rate should be lower.

In current production, it is called low-speed grinding when the rotation rate is less than 76% of the critical turns, and it is high-speed grinding when the rate is higher than 88% of the critical turns. It will be called supercritical speed grinding if the rate is greater than 100%.

As a matter of fact, if ball mill uses smooth liner, the media filling rate is between 30-40%, and appropriately reducing grinding concentration to make the rate of turns improved to 100-104% of critical turns, the processing capacity can be increased by 10-30%. Only with some of the above conditions can high-speed grinding be used, but it will also bring harm to reduce the fineness of grinding, so users cannot pursue the ball mill with high turns one-sidedly.