Ways to Improve Grinding Efficiency at Sound Consumption of Grinding Balls

General Introduction :

Consumption of grinding balls in miner grinding process is very high,over ten times of liner consumption. To feed up loss and maintain similar sizes distribution of grinding ball load,new grinding balls should be added at certain proportion. As we know,consumption of grinding balls is due to mechanical wearing and corrosion loss,which happens during irreversible process of physics-mechanical or physics-chemical on surface of solid. Thus,how to reduce the consumption of grinding balls effectively on the precise without any harm to the ball mill?

I. To improve grindability of ores

Sizes of feed materials to the ball mill is one of critical factors influencing grinding media consumption. The idealer of ore grindability,the finer of feed material sizes.As of result,powder consumption becomes less due to lower consumption of grinding media.Not,the other way.

During the actual production,in case of high hardness or fine-sized ores required,certain chemical additives can be considered to improve ore grindability and grinding efficiency if economically allowed; or heat treatment upon ores to reduce its hardness by changing the mechanically property of ores if sufficient land.

II. To Reduce Feed Sizes

The bigger of mill feed sizes,the more work of ball mill upon raw materials. Thus in order to achieve required fineness,work for ball mill certainly increases. Therefore,consumption of grinding balls goes higher.

To reduce power consumption of ball mill, feed sizes of ores to mill should be smaller. That is to say,discharge sizes of previous process,ores crushing should be smaller.

III. Proper Filling Rate of Grinding Balls

When rotation of ball mill reach certain stable speed,high filling rate enables more times of grinding balls upon inside materials with larger grinding area and quicker wearing. When that goes extremely high, travelling status will be changed, and grinding efficiency goes down. On the contrary,grinding efficiency can be weaken at low filling rate.

Filling rate is between 45-50% during ore grinding process in the mining plants. But it may not be proper one if actual mining condition of each site is considered. Thus mining tests should be carried out to determine best filling rate.

IV.Reasonable Grinding Ball Sizes and Sizes Distribution

Grinding balls and materials inside ball mill is point contact. If higher diameter of grinding balls ,the quicker wearing due to stronger crushing strength,in addition,materials broke along penetration force easily,influencing grinding efficiency.

On the other side,when filling rate of grinding balls is same,load becomes less for ones with bigger diameter,leading to uneven grinding sizes :some with lower grindability,while others  over grinded. If diameter of grinding balls becomes smaller,crushing strength upon ores will be lower at lower grindability. Proper sizes of grinding balls and sizes distribution not only reduces consumption but also increases grinding efficiency.

V. Rational Grinding Concentration

Concentration of ore-grinding influences specific gravity of slurry,material adhesion surrounding grinding balls and slurry fluidity. That is,high concentration enables sound adhesion,high impact and grinding. But grinding ball consumption is fast.

Feed amount of ores and water,classification should be adjusted well to maintain idea concentration during actual production.

VI. Logical Control of Ball Mill Rotation Speed

On the promise of sound distribution of grinding balls,which drop like throwing objects when ball mill starts to rotate. Rotation can increases to ideal degree when active power reach its climax,sound grinding efficiency and reasonable consumption.

In theory,critical rotation is 78～84%.Actual rotation is decided by material property and other factors.

Conclusion: There are other factors influencing consumption of grinding balls as well,even some of them hardly to specify. Final technical and economical index, and sound product quality index should be considered comprehensively.