Grinding Balls Determine Powder Fineness

As the demand for powder fineness continues to increase, ultrafine grinding equipment such as ball mills, bead mills, and high-speed vibrating mills are playing an increasingly important role. In the use of ultrafine grinding equipment, the selection of grinding media is a crucial factor. It determines the cost, grinding efficiency, and the quality of the final product in the grinding process. The material, density, hardness, size, shape, filling rate, production method, and grading of the grinding media all have a significant impact on the powder fineness.

The Influence of Grinding Media Material on Crushing Effect

The material of the grinding media balls determines the cost and powder fineness of the process. Differences in the chemical composition of the grinding media affect their crystal structure, which in turn determines their compressive strength and wear resistance. The composition also influences the density and hardness of the grinding media.

The wear of the grinding media and the grinding time directly affect the purity of the product. Wear and failure of the grinding media balls lead to media loss, thus increasing the cost of the grinding process. From a product quality perspective, continuous wear of the media during grinding causes fine particles to mix into the product, leading to contamination.

The density and hardness of the grinding media balls play a key role in grinding efficiency: The higher the density of the media, the higher the grinding efficiency. The harder the media, the smaller the wear, and the easier it is to ensure product purity. However, under certain conditions of slurry density and viscosity, higher density and hardness are not always better. Pursuing excessively high density and hardness not only increases cost but also leads to a series of undesirable effects.

Common grinding media in the market include glass beads, zirconium silicate beads, steel balls, alumina balls, and zirconia balls.

Glass Beads

Glass beads are inexpensive but have low density, low grinding efficiency, are prone to breaking, and exhibit high wear. They can easily lead to product contamination, so newer equipment rarely uses this material.

Alumina Grinding Media Balls

Alumina (Al₂O₃) grinding media balls are ceramic balls made primarily of Al₂O₃, also called Al₂O₃ porcelain balls. Al₂O₃ ceramics have excellent properties such as wear resistance, corrosion resistance, high-temperature resistance, and impact resistance.
Thus, Al₂O₃ porcelain balls are widely used in industries like white cement, mineral processing, ceramics, electronic materials, magnetic materials, as well as in coatings and paints. The higher the Al₂O₃ content, the greater the hardness and wear resistance of the ceramic balls.

Zirconium Silicate Grinding Media Balls

Zirconium silicate (ZrSiO₄) grinding media balls are made from ZrSiO₄ as the main raw material, with a ZrO₂ content of 65%-68% or lower. ZrSiO₄ ceramic balls are mainly used for ultrafine grinding of ZrSiO₄ raw materials, improving the ZrSiO₄ content. However, their high wear rate and low strength limit their application.

Zirconia Grinding Media Balls

Zirconia (ZrO₂) grinding media balls are ceramic balls with more than 90% ZrO₂ content, stabilized with additives. Compared to Al₂O₃ ceramic balls, ZrO₂ ceramic balls offer higher wear resistance and grinding efficiency. ZrO₂ ceramic balls are efficient, prevent contamination, and have smooth, hard surfaces, excellent roundness, and a reasonable size distribution. They possess high hardness, strength, toughness, wear resistance, and corrosion resistance, offering high production efficiency and lower costs. Zirconia ceramic balls are widely used in industries such as ceramics, building materials, chemicals, coatings, electronics, machinery, food, pharmaceuticals, and cosmetics.

The Shape and Size of the Grinding Media Have a Significant Impact on the Grinding Effect

The shape of the grinding media is mainly spherical, cylindrical, and irregular. In industrial applications, irregular media tend to experience more wear, leading to noticeable contamination. Therefore, spherical media are most commonly used, while cylindrical media also have some applications. Irregular media are rarely used.

The size of the grinding media balls directly affects the grinding efficiency and powder fineness. It determines the number of contact points between the media and the material. Smaller media balls, at the same volume, have more contact points, which theoretically leads to higher grinding efficiency. The media size should be selected based on the material particle size and the required product fineness. The finer the product, the smaller the media size. If the feed particle size is large and the grinding process requires a strong impact for fragmentation, larger media should be used.

Conclusion

It is clear that different grinding media balls have a significant impact on the grinding effect. In practical production, it is important to select the appropriate grinding media balls and strictly control the balling process. Optimizing the production process to improve grinding efficiency, while minimizing wear on the media, helps ensure the stability of product quality.

Epic Powder

Epic Powder, 20+ years of work experience in the ultrafine powder industry. Actively promote the future development of ultra-fine powder, focusing on crushing, grinding, classifying and modification process of ultra-fine powder.  Contact us for a free consultation and customized solutions! Our expert team is dedicated to providing high-quality products and services to maximize the value of your powder processing. Epic Powder—Your Trusted Powder Processing Expert !