Ball mill grinding efficiency is low, low processing capacity, high production energy consumption, product fineness is not stable and so on is most of the peers will encounter the problem.How to effectively improve the grinding efficiency of ball mill is an important problem.Below, we share 10 ways to improve the grinding efficiency of the ball mill!
a, change the grindability of the raw ore
The hardness, toughness, dissociation and structural defects of the raw ore determine the degree of grinding difficulty.Small grindability is easy to grind the ore, the mill lining plate and steel ball wear is smaller, energy consumption is also small;If not, it’s the other way around.Raw ore properties directly affect the productivity of the mill.
In production, if the ore is difficult to grind or the ore requires fine grinding, it can be considered to take a new treatment process to change the grindability of the ore if the economic and site conditions permit:
One method is to add certain chemical agents in the grinding process to improve the grinding effect and increase the grinding efficiency;
Another method is to change the grindability of the ore, for example, to heat the minerals in the ore, change the mechanical properties of the whole ore, reduce hardness and so on.
b, more crushing less grinding, reduce grinding granularity
Large grinding particle size, the mill needs to do more work on the ore, to achieve the specified grinding fineness, the workload of the ball mill is bound to increase, then, energy consumption and power consumption will also increase.
To reduce the feeding particle size of grinding, it requires the particle size of crushing products to be small, that is, to “more crushing less grinding”.Moreover, the efficiency of crushed ore is obviously higher than that of grinding, and the energy consumption of crushed ore is lower, about 12%-25% of the energy consumption of grinding.
c. Reasonable filling rate
When the speed of the ball mill is constant and the filling rate is large, the ball will hit the material more times, the grinding area is large, the grinding effect is strong, but the power consumption is also large, and the filling rate is too high, it is easy to change the motion state of the ball, and reduce the hitting effect on the large particle material.On the contrary, the filling rate is too small, and the grinding effect is weak.
At present, many mines set the filling rate as 45%~50%, which is not necessarily reasonable strictly speaking, because the actual conditions of each dressing plant are different, so it is not possible to achieve the ideal grinding effect by applying others’ data for ball loading. It depends on the situation.
d, reasonable steel ball or zirconia bead size and ratio
Because the steel ball in the ball mill is in point contact with the ore, and the ball diameter is too large, the crushing force is also large, leading to the crushing of the ore along the direction of penetration force, rather than along the grain interface of different minerals with weak binding force. The crushing is not selective and does not meet the grinding purpose.
In addition, in the case of the same ball filling rate, too large ball diameter leads to too few steel balls, low crushing probability, aggravated overcrushing phenomenon, and uneven product particle size.The steel ball is too small, the crushing force of the ore is small, and the grinding efficiency is low. Therefore, the precise size and ratio of the steel ball are very important to the grinding efficiency.
e. Accurate adding zirconia bead
In the production, the grinding effect of steel ball and ore will cause the wear of steel ball, resulting in the change of the ratio of steel ball of various sizes, affecting the grinding process and resulting in the change of the fineness of grinding products, so it needs a reasonable system of steel ball supplement to make the production stable.
f. Appropriate grinding concentration
The grinding concentration affects the specific gravity of the pulp, the degree of adhesion of the ore particles around the ball and the fluidity of the pulp.
The grinding concentration is low, the pulp flow is fast, and the adhesive degree of the material around the steel ball is low, so the impact and grinding effect of the steel ball on the material is weak, the ore discharging size is not qualified, and the grinding efficiency can not be played.
The grinding concentration is high, the material around the steel ball adhesion degree is good, the impact and grinding effect of the steel ball on the material are good, but the pulp flow is slow, easy to cause the material over crushing, more is not conducive to improve the mill handling capacity.
In production practice, the grinding concentration is often controlled by controlling the amount of ore fed by the mill, or the water supply of the mill, or adjusting the grading effect, and controlling the particle size composition and water content in the grading returned sand.
g, optimize the grinding process
In actual production, the grinding process can be optimized according to the ore properties of the raw ore, such as the dissemination size of useful minerals, the degree of monomer dissociation, and the dissemination size of gangue minerals.Such as pre-tailing, pre-enrichment, stage grinding, pre-classification and other operations to optimize the grinding system, on the one hand to reduce the amount of grinding, on the one hand to carry out early recovery of useful minerals.
h. Improve grading efficiency
The effect of classification efficiency on grinding efficiency is self-evident.High grading efficiency means that qualified particle size can be discharged in a timely and efficient manner, while low grading efficiency means that most of qualified particle size products are not discharged and return to the mill for regrinding, which is easy to cause over-grinding, thus affecting the separation effect in the later stage.
The efficiency of classification can be improved by using two-stage classification or improving classification equipment.
i, appropriately improve the grading sand return ratio
Sand return ratio is the ratio between the sand return amount of the ball mill and the raw ore feed amount, and its size directly affects the productivity of the mill.One way to improve the sand return ratio is to increase the original ore feed, and the other way is to reduce the shaft height of the spiral classifier.
However, the improvement of sand return ratio also has a certain limit.When it increases to a certain value, the productivity of the mill increases very little, and the total ore feed of the mill is close to the maximum processing capacity of the mill, which is easy to cause swelling, so the return sand ratio should not be too large.
j. Automatic control of grinding system
There are many variable parameters in the grinding operation, a change will inevitably cause many factors to change one after another, if the use of artificial operation control will inevitably cause the production of instability, and the automatic control of grinding operation can make the grinding classification maintain stable and suitable for the requirements of the state, also can improve the grinding efficiency.
According to foreign reports, the automatic control of the grinding classification circuit can increase the production capacity by 2.5%~10%, and the power consumption can be saved by 0.4~1.4kWh/t for processing one ton of ore.
In grinding process, many factors affect the grinding efficiency, many factors can only qualitative analysis, it is difficult to make quantitative analysis, this needs according to the actual production situation and the result of the qualitative analysis to comprehensive analysis, thus draws the reasonable parameters, guide field production, to reduce production costs, achieve the goal of saving energy and reducing consumption.
The most important is to choose right and reliable zircnoia beads vendor, such as SANXIN New Materials, one famous zirconia beads vendor.
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Post time: Mar-03-2021