• Loading amount of alumina grinding balls:

Generally, it is 30% - 35% of the effective volume of the ball mill. For a ball mill with a diameter of 1.76 meters, assuming its effective length is L meters, then the effective volume of the ball mill is: V = π * (1.76/2)^2 * L. The loading amount is 30% to 35% of V.

Different grinding methods also have a certain impact on the loading amount: In the wet grinding process, when the loading amount of alumina balls reaches 55% of the net volume of the ball mill, a better state can be achieved. In the dry grinding process, the loading amount is generally 30% - 35% of the effective volume of the ball mill.

• Initial ratio of grinding balls:

Generally, the initial ratio of alumina ceramic balls is 30% large balls, 40% medium balls, and 30% small balls. For example, if the ball loading amount of a 1.76m ball mill is 10 tons, then 3 tons of large balls (such as 40mm), 4 tons of medium balls (such as 30mm), and 3 tons of small balls (such as 20mm) are loaded.

Function of large balls: Provide impact force, crush large particle materials, suitable for materials with large initial particle size (such as >1mm) or high hardness (such as quartz, feldspar).

Function of medium balls: Take into account both impact and grinding, undertake the crushing of intermediate particle sizes, suitable for medium-hardness materials (such as ceramic坯料) or materials with medium initial particle size (0.5-1mm).

Function of small balls: Fine grinding, improve the fineness of the finished product, target fineness requirements are high (such as <200 mesh) or wet grinding.

• Adjustment of the ratio under the influence of other factors:

(1) Particle size of grinding materials: If the particle size of the material to be ground is large or the hardness is high, the proportion of large balls can be appropriately increased to enhance the impact and crushing ability of the material. For example, for materials with a particle size greater than 10mm, the proportion of large balls can be increased to 40%, medium balls reduced to 35%, and small balls remain at 25%.

(2) Fine grinding requirements: The proportion of small balls can be increased to 40%, and the filling rate can be reduced to 35% to avoid excessive crushing.

(3) Grinding method: In the wet grinding process, due to the better fluidity of the material, the amount of large balls can be appropriately reduced, and more medium and small balls can be used to ensure a good grinding effect. For example, during wet grinding, the proportion of large balls can be reduced to 25%, medium balls increased to 50%, and small balls remain at 25%. In the dry grinding process, the proportion of large balls can be appropriately increased to enhance the impact on the material.

(4) Ball mill rotation speed: The rotation speed of the ball mill also affects the ratio of grinding balls. When the rotation speed is high, the impact force of the grinding balls is large, the proportion of large balls can be appropriately reduced, and the proportion of small balls can be increased to improve the grinding effect. For example, when the ball mill rotation speed is 80% of the critical rotation speed, the proportion of large balls can be reduced to 35%, medium balls remain at 40%, and small balls increased to 25%.

(5) In actual production, the ratio can be fine-tuned according to the grinding effect and production requirements. For example, if the particle size of the ground material is found to be too coarse, the proportion of small balls can be appropriately increased to enhance the grinding effect; if the particle size of the ground material is too fine, the proportion of large balls can be appropriately increased to improve the grinding efficiency.

• Maintenance and optimization:

Regular ball replenishment: The monthly wear rate of alumina balls is about 0.5% - 1%, and they need to be checked and replenished monthly to maintain a stable ratio.

Screening optimization: The machine should be stopped for screening every 3 - 6 months to remove debris and small balls to avoid ineffective filling.

Energy consumption monitoring: If the unit energy consumption increases by more than 10%, the ratio needs to be re-adjusted or the wear condition of the balls needs to be checked.

• Precautions:

The actual ratio needs to be determined through small-scale trials. It is recommended to first run with median parameters and gradually optimize according to the particle size distribution of the discharge (screen residue analysis).