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Five factors affecting the grinding efficiency of ball mill

Date:2019-06-05 11:12     writer:cement editor     Views:


  Some factors that affect the grinding efficiency of ball mill, such as the movement form of steel ball in the cylinder, the rotation rate, the addition and size of steel ball, the level of material, and the use of grinding aid. These factors have an impact on the efficiency of ball mill to a certain extent.

  1. Movement form of steel ball in cylinder

  To a certain extent, the movement of grinding medium in the cylinder affects the grinding efficiency of ball mill.

  The working environment of the ball mill is divided into the following categories:

  The main results are as follows: (1) in the surrounding and laxative movement area, the filling amount in the cylinder is less or not, so that the material can do uniform circular motion or laxation motion in the barrel, and the impact probability of steel ball and steel ball increases. The wear between the steel ball and the liner further makes the efficiency of the ball mill low.

  (2) throwing the moving area, and the filling quantity is suitable. in that case, the steel ball impact the material so that the efficiency of the ball mill is relatively high;

  (3) in the area around the center of the ball mill, the circumferential motion of the steel ball or the mixture of the falling motion and the falling motion make the movement range of the steel ball limited and the wear and impact less;

  (4) in the blank area, the steel ball does not move, and if the filling amount is too large, the motion range of the steel ball is small or does not move, the resource waste can be caused, and the ball mill can be easily caused to fail.

  As can be seen from (1), when the filling amount is very little or even no, the ball mill suffers a large loss, and the loss mainly comes from the impact of the steel ball on the material. Now the general ball mill is horizontal, in order to effectively reduce the loss of the ball mill to the material without material, the vertical ball mill is present. in the traditional ball-milling equipment, the barrel of the ball mill is rotating, and the barrel of the stirring type equipment is stationary, the steel ball and the material in the barrel are disturbed and stirred by the spiral stirring device, and the ball and the material rotate in the equipment under the action of the vertical stirring device, so that the material can act only in combination with the steel ball until the material is crushed, so the material Grinding and fine grinding are very suitable.

  2、 Rotating rate

  One of the important working parameters of the ball mill is the rotation rate, which directly affects the grinding efficiency of the ball mill. When considering the conversion rate, the filling rate should also be considered. The filling rate is positively correlated with the rotation rate. When discussing the rotation rate here, keep the filling rate at a certain rate. No matter what the motion state of the ball load is, there will be the most suitable rotation rate under a certain filling rate.

  When the filling rate is low, the energy obtained by the steel ball is low, and the impact energy on the material is low, which may be lower than the crushing threshold of the ore particles, resulting in invalid impact on the ore particles, that is to say, the ore particles will not break, so the grinding efficiency of low speed is low.

  With the increase of rotating speed, the impact energy of steel ball impinges on the material increases, which increases the crushing rate of coarse ore particles, and then improves the grinding efficiency of ball mill. If the rotating speed continues to increase, when the speed is close to the critical speed, the coarse product is not easy to be broken, which is because after the high rotation rate, although the impact energy of the steel ball increases, the number of cycles of the steel ball decreases a lot. In unit time, the impact times of steel ball and the crushing rate of coarse ore particles are reduced.

  3. Addition and size of Steel Ball

  If the addition amount of the steel ball is improper, the ball diameter and the proportion are not reasonable, the grinding efficiency can be reduced. The wear of the ball mill in the working process is relatively large, and a large part of the reason is that the ball mill is not controlled well when the steel ball is manually added, so that the steel ball is accumulated to form a ball-like phenomenon, and then a certain abrasion is generated on the machine.

  The steel ball is used as the main grinding machine medium of the ball mill, and the addition quantity of the steel ball is not only to be controlled, but also the proportion of the steel balls is controlled. And the grinding efficiency is improved by about 30% by optimizing the ore grinding medium. In the process of grinding, the ball diameter is large, the impact and wear are large, the grinding wear is small, the ball diameter is small, the impact wear is small, and the grinding wear is large. When the ball diameter is too large, the number of loading in the barrel is reduced, the grinding area of the ball load is small, the abrasion of the lining plate and the consumption of the ball are increased. If the ball diameter is too small, the cushioning effect of the material is increased, and the impact grinding effect is reduced.

  in order to further improve that efficiency of the grinding, a method of precise assembly of the ball-up ball is proposed:

  (1) carrying out screening analysis on a specific ore, and grouping according to the size of the particle size; (2) analyzing the anti-crushing performance of the ore, and calculating the precise ball diameter required by each group of ore particles by using a spherical diameter semi-theoretical formula; and (3) guiding the ball distribution according to the material size composition characteristic of the material to be ground, In order to obtain the maximum crushing probability, the ratio (4) of the various steel balls is carried out according to the basis of the ball-filling calculation, the type of the complementary ball is reduced, and the two-three kinds of steel balls can be added.

  4. Material level

  The material level affects the filling rate, and then affects the grinding effect of ball mill. The material level is too high, which will cause the ball mill to block coal. Therefore, it is very important to monitor the material level effectively. At the same time, the energy consumption of ball mill is also related to the material level. For the intermediate warehouse flour making system, the power consumption of the ball mill accounts for about 70% of the electricity consumption of the flour making system and about 15% of the power consumption of the power supply. There are many factors that affect the intermediate warehouse flour making system, but under the influence of many factors, it is very necessary to check the material level effectively.

  5. Liner selection

  The lining plate of the ball mill not only can reduce the damage of the cylinder, but also can transmit energy to the grinding medium. And one of the factors affecting the grinding efficiency of the ball mill is determined by the working surface of the liner. In practice, it is known that to reduce that damage of the cylinder and to improve the grinding efficiency, it is necessary to reduce the slip between the grinding medium and the liner, so that the shape of the working surface of the lining plate and the friction coefficient between the lining plate and the grinding medium are mainly used. The high-manganese steel lining board is used before, and the rubber lining board, the magnetic lining board, the corner spiral lining board and the like are now installed. The modified liner not only is higher in performance than the high manganese steel liner, but also can effectively prolong the ball. The service life of the mill.

  The grinding efficiency can be effectively improved by improving the movement state, rotation rate, size, material level and liner material of the ball in the ball mill.

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