In the grinding operation, the consumption of ball mill steel ball is very large, about 10 times more than the loss of ball mill lining plate.In order to make up for the loss of steel ball and keep the ball size unchanged in the mill, it is necessary to add steel ball regularly according to a certain ratio.
The consumption of ball mill steel is mainly caused by mechanical wear and corrosion wear, which is an irreversible process of "physical-mechanical" and "physical-chemical" occurring on the solid surface. So on the premise of ensuring the quality of grinding the ball mill,how to reduce ball abrasion of ball mill?
1. Change the grindability of ore
The grindability of feed material to the ball mill is one of the reasons that affect the energy consumption of ball mill steel ball. Generally, if the grindability of feed material is small, the ore is easy to wear.Conversely, the opposite is true.
In the actual production, if the ore is difficult to grind or the ore requires fine grinding, it can be considered that certain chemical agents can be added in the grinding process to improve the grinding effect and increase the grinding efficiency if the economic and site conditions allow.Or the ore is heated to change the mechanical properties of the whole ore, reducing the hardness of the mineral.These two methods can effectively reduce the energy consumption of the ball mill.
2. Reduce feed particle size
The ball mill into the grinding particle size is large, the work of the ball mill on the material is also larger, in order to reach the specified grinding fineness, the workload of the ball mill is bound to increase, then, the energy consumption of the steel ball will increase.
In order to reduce the power consumption of the ball mill, the feed particle size of the ore can be reduced. Therefore, the product particle size of the ore is required to be small, that is, "more crushing and less grinding" should be achieved.
3. Control the filling rate of steel ball
When the rotation speed of the ball mill reaches a certain degree, the filling rate is large, and the steel ball strikes the material more times, the grinding area is large and the wear is fast. In addition, the filling rate is too high, and the movement state of the ball of the ball of the ball mill will be changed, reducing the impact effect on the large particle material.On the contrary, if the filling rate is too small, the grinding action is weak.
At present, the filling rate of steel ball in mill operation is generally 45%~50% for grid mill and 38%~42% for overflow mill.If according to the actual situation of each dressing plant, it is not a reasonable filling rate, so it is necessary to determine a reasonable filling amount through the dressing test.
4. Control the size and proportion of steel ball
Because the steel ball in the ball mill and the material is point contact, if the steel ball diameter is too large, the crushing force is large, it will lead to excessive wear, and easy to cause the material along the direction of penetration force broken, affecting the grinding efficiency.
In addition, under the same filling rate of steel balls, if the ball diameter is too large, the individual number of steel balls will be less, the probability of breakage will be low, over-crushing phenomenon will be intensified, and the product granularity will be uneven.The ball is too small, the crushing force on the ore is small, and the grinding efficiency is low.Therefore, reasonable steel ball size ratio can not only reduce steel consumption of the ball mill, but also effectively improve grinding efficiency.
5. Control grinding concentration
The grinding concentration will affect the specific gravity of the pulp, the adhesion of the material around the ball and the fluidity of the pulp.If the grinding concentration is appropriate, the adhesive degree of the material around the steel ball is good, the impact and grinding effect of the steel ball on the material is also great, and the steel ball wears away quickly.
In actual production, the grinding concentration can be controlled by controlling the amount of ore feed, water supply, or adjusting the grading function.
6. Control the ball mill speed
On the premise of reasonable steel ball ratio of ball mill, with the increase of ball mill speed, the steel ball inside the cylinder will be in the state of dropping down to drop pile. When the rotation rate increases to a certain level, the useful power will reach the upper limit. At this time, the grinding effect is better and the wear of ball mill is also reasonable.
The theoretical critical speed of ball mill is generally 78 ~ 85%.Due to the nature of materials and other factors, the ball mill speed should be determined according to the actual situation.
In addition, the quality of steel ball size affect productivity, also influence the ball high and low consumption, which affect the grinding cost, when choosing a steel ball, the ball is not a very hard time, but has its proper hardness value, if only considering the ball consumption, is the higher the hardness of lower consumption, but for mill productivity, within a certain range productivity increases with increasing ball hardness, but when the hardness is over a certain range is harmful to mill productivity, make the mill productivity, and the steel ball is fragile.Second, the steel ball density of ball mill is also a problem that cannot be ignored.
In the process of grinding, there were many factors affecting energy consumption of ball mill ball, and most of the factors is difficult to make quantitative analysis, can only be qualitatively analyzed, to guarantee the quality of reasonable index under the premise to reduce the power consumption of steel ball for ball mill, must to consider from multiple link, and good control of each link, to achieve good technical and economic indexes and product quality indicators.
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