Grinding fineness is one of the many factors affecting the beneficiation index, and the size of grinding fineness directly affects the high and low grade of concentrate and the recovery rate of the product. How to effectively and reasonably control the grinding fineness is an important factor to directly reduce the cost of beneficiation and improve the economic efficiency of the plant. Factors affecting the fineness of grinding are: hardness of raw ore, size of crushing size, screen holes, feed size, ball mill model, number of steel balls, the proportion of steel ball size, ball mill liner wear, ball mill speed, classifier speed, classifier spindle lifting height, classifier blade wear, classifier overflow weir high and low, the lower opening of the classifier high and low, the size of the lower opening of the classifier, classifier opening high and low, the upper opening of the classifier size, the water flow at the sand return. The size of the opening of the classifier, the size of the water flow at the sand return, the size of the water supply to the ball mill, the size of the flushing water at the discharge of the ball mill, and so on.

1、Ore hardness

Reasonable allocation can be carried out, as far as possible to make the ore size uniform, lumpy, powdery ore ratio reasonable and smooth. In addition to the ball mill belt to the ore, the belt due to long time wear and tear may leak ore, leakage of most cases is powder ore, this part of the leakage of ore must be added as much as possible in a timely manner to the ball mill, if a long time to pile up, centralised to add, will cause the ball mill to the ore is not uniform, resulting in the production of instability. Especially difficult to select the ore, often powder minerals and lump minerals are not the same nature.

2, crushing size

Ball millers must supervise the crushing system, if the ball mill in the production of ore size changes, must be immediately reflected to the crushing workshop. The finer the crushing size, the better.

3、Ball mill model, rotating speed, feed amount, number of steel balls, steel ball size: note that when you buy to check the consultation.

4、Classifier spindle height elevation

Some mineral processing plant ball millers in the equipment overhaul, due to the classifier in the mineral sand is not cleaned up, in a long period of time under the sinking set, the mineral sludge sinking more solid, in the lowering of the main shaft of the classifier, due to the lack of care, did not put the main shaft completely down, resulting in less sand return than normal. In addition, the spindle is not put down may also be due to the spindle for a long time without cleaning oil, so in the operation process should be noted.

5、Blade wear

After the blade is worn, the amount of sand return will be reduced, resulting in coarser grinding fineness, in addition, if the blade is worn out, it will affect the life of the classifier, so check the wear of the blade in time during the work, and replace the worn out blade in time.

6、Classifier overflow weir height

It affects the size of the sedimentation area of the ore, in the production, we can adjust the height of the overflow weir of the classifier appropriately according to the requirements of the fineness of the grinding ore, if the fineness of the grinding ore is required to become fine, the angle iron can be welded on both sides of the classifier at a certain height, and the method of inserting the wooden spanner can be used to adjust the height of the overflow weir of the classifier, and the overflow weir of the classifier can be naturally improved sometimes by the accumulation of the slime for a long period of time.

7、The height of the lower opening of the classifier and the size of the lower opening of the classifier.

During the installation of equipment for field production, in many processing plants, because in the installation of equipment in the classifier opening size and height is not adjusted, and workers in the operation process is not too pay attention to, invisible is also affect the grinding operation. The lower opening of the classifier is low, relative to the ore precipitation area is large, so the amount of sand will be large, grinding fineness is relatively fine, the lower opening of the classifier is large, relative to the ore precipitation area is large, the water flow is more gentle, so the amount of sand will be large, the grinding fineness is relatively fine, the upper opening of the classifier is low, the amount of sand is relatively large, the grinding fineness is relatively fine, the upper opening of the classifier is large, relative to the amount of sand is relatively large, the grinding fineness is relatively fine. Otherwise, it is the opposite.

8、Return to the sand at the size of the water flow

In many mines are not grinding automation, the size of the water, directly from the ball miller to manually adjust, because the two places of the water flow is large, increase and decrease is difficult to see, so must require careful observation and fine adjustment.

9, ball mill water supply size

Ball mill water supply increases, the grinding concentration becomes thin, the grinding fineness will become coarse, on the contrary, the ball mill water supply decreases, the grinding concentration becomes large, the grinding fineness will become fine.

10, ball mill discharge at the mouth of the flush size

Ball mill discharge at the mouth of the flushing water becomes larger, the overflow becomes thinner, the overflow fineness becomes fine. On the contrary, the ball mill discharge at the mouth of the flushing water becomes smaller, the overflow becomes thicker, the overflow fineness becomes coarse. So in other conditions, including the amount of ore unchanged, to improve the grinding fineness, you can reduce the ball mill water supply, ball mill discharge at the flushing water increase, it is best to adjust these two conditions at the same time to ensure that as far as possible because of the adjustment of the grinding fineness caused by the adjustment of the amount of ore paddle changes caused by the flotation fluctuations. Under the premise of grinding fineness is guaranteed, the feeding capacity of ball mill can be greatly increased.