High-purity alumina is a precious material known for its excellent hardness, high brightness, electrical insulation and high corrosion resistance.

Alumina is used for different purposes and fetches different prices depending on the level of purity – the purer it is, the more valuable it is. For example, the alumina coating process of lithium battery separator is a sensitive process, which has specific requirements on the purity, particle size, morphology, surface modification, product stability, etc. of alumina powder. Therefore, the cost requirements for alumina materials are higher.

In powder making, grinding balls are a key component of the physical grinding process required to obtain ultra-fine powders of high purity.

These tiny spheres, ranging in size from 0.1mm to 100mm or more, are one of the most central components of the grinding process and play an important role in wet grinding and powder size reduction.

Unsurprisingly, aluminum oxide is one of the top choices for grinding ball selection – along with silicon nitride, zirconia, boron nitride, and others. The final choice of materials often depends on the end product that needs to be produced.

How could this be?It should be noted that no matter how good the wear resistance of the grinding media ball is, it cannot completely avoid wear. As a result, the worn part of the grinding ball will mix with the material being ground, resulting in contamination of the final product.

Here is an example: Although the popular zirconia ball is known for its high density and hardness, it can generate up to 6000ppm of attrition during the grinding of alumina powder—enough to reduce the purity of the resulting alumina powder by several notches.

This is why manufacturers will try their best to choose grinding balls of the same or similar material when grinding high-purity alumina and other powdery materials, in addition to factors such as good sphericity, high density, and wear resistance.

Highly wear-resistant alumina balls are currently imported from Japan at sky-high prices — starting at as much as $308 per kilogram.
The question on the mind of most manufacturers - do I have to choose between cost and purity?

The alumina content in Johncera's proprietary alumina balls is higher than the industry standard of 99%, and the silica content is kept at a maximum of 0.2%. The benefit of this high purity? Better chemical stability and higher hardness. Our highly inert alumina grinding balls are perfect for any process involving high temperatures or reactive acid-base environments.

Enhanced Strength And Durability:

Our 99% alumina balls have a Mohs hardness greater than 8.9 - making it one of the hardest materials available! Because of this, it significantly reduces wear and thus prolongs the life of the grinding media. Longer service life, lower costs and downtime of production runs.

High Specific Gravity: 

The specific gravity of Johncera ceramic grinding balls is higher than 3.9g/cm³, which is again higher than the industry benchmark. This benefit? This increased density helps to significantly increase grinding efficiency, reduce grinding time, and save energy consumption, thereby reducing costs.

Interested in learning more about this product or looking for a quote for Aluminum Oxide Grinding Balls? Please email sales@johncera.com to discuss with us.