Ten tricks for improving grinding efficiency of ball mill-2
6.Proper grinding concentration
The grinding concentration affects the pulp’s specific gravity, the adhesion of ore particles around the ball, and the fluidity of pulp.
Low grinding concentration, fast slurry flow, low adhesion of material around the ball, so that the impact of the ball on the material and weak grinding role, the size of ore discharge unqualified, grinding efficiency can not be played;
The grinding concentration is high, the adhesion of the material around the steel ball is good, the impact of the steel ball on the material and the grinding effect are good, but the ore slurry flow is slow, easy to cause the material to be too crushed, and is more unfavorable to increase the mill processing capacity.
In production practice, the concentration of grinding is controlled by controlling the amount of ore feed, or the amount of water supplied by the mill, or by adjusting the classification function and controlling the size composition and water content of the sand returned from the classification.
7.Optimize grinding process
In practice, the grinding process can be optimized according to the ore properties of the raw ore, such as the particle size of the useful minerals, the dissociation degree of the monomer, and the particle size of the gangue minerals. On the one hand, pre-tailing, pre-enrichment, stage grinding, pre-classification, and other operations to optimize the grinding system, on the one hand, reduce the amount of grinding the early recovery of useful minerals.
8.Improve classification efficiency
The effect of classification efficiency on grinding efficiency is self-evident. High classification efficiency means that qualified particles can be discharged in time and efficiently. In contrast, low classification efficiency means that most qualified particles are not removed and returned to the mill for re-grinding.
The efficiency of classification can be improved by adopting two-stage classification or improving classification equipment.
9.Properly increasing the ratio of sand return in classification
Return Sand ratio is the ratio of return sand quantity of ball mill to ore feed quantity, which directly affects the productivity of the ball mill. One way to increase the return sand ratio in the concentrator is to increase the ore feed; the other way is to reduce the spiral classifier’s shaft height.
However, there is a limit to the increase of the sand return ratio. When it increases to a specific value, the increase in mill productivity is minimal. The mill’s total ore feed is close to the maximum processing capacity of the mill, so the return sand ratio should not be too large.
10.Automatic Control of grinding system
There are many variable parameters in grinding operation; one change will cause many factors to change one after another, if the artificial operation control is adopted, it will cause instability of production, the automatic control of grinding operation can keep the grinding classification stable and suitable for the requirements, and can also improve the crushing efficiency.
According to foreign reports, the automatic control of grinding and classification circuit can increase the production capacity by 2.5% ~ 10%. The power consumption can be saved by 0.4 ~ 1.4 kWh/t for one ton of ore.
In the grinding process, many factors affect the grinding efficiency. Many factors can only be analyzed and judged qualitatively, and it isn’t easy to make a quantitative analysis. This requires a comprehensive analysis based on the actual production situation and the results of qualitative analysis; the reasonable parameters are obtained to guide the field production to reduce the production cost and achieve the goal of energy-saving and consumption reduction.