How to Select Grinding Media
Grinding media comprise a wide range of objects such as grinding balls, beads and satellites, as well as more rare shapes like cylinders, diagonals and ballcones. The media itself can be composed of a variety of materials, including carbon steel, stainless steel, chrome steel and non-metallics like steatite or ceramics.
Selecting the right grinding media for a specific application depends upon several factors, some of which are interrelated:
- Initial feed size – Smaller media cannot easily break up large particles.
- Final particle size – Smaller media are more efficient when ultrafine particles are desired.
- Specific gravity – In general, high-density media give better results. The media should be more dense than the material to be ground. Also, highly viscous materials require media with a higher density to prevent floating.
- Hardness – The harder the media, the better the grinding efficiency and, consequently, the longer the wear.
- Discoloration – Some media may cause light-colored slurry to turn gray.
- pH – Some strong acid or basic slurries may react with certain metallic media.
- Contamination – Material resulting from the wear of the media may affect the product and may need to be removed by a magnetic separator, chemicals, or a sintering process.
- Consistency in size – Although more important with mini media, ideally one wants all the same size. In these small sizes, there are ranges because, due to the manufacturing process, the media must be classified or screened.
- Costs – Media that may be 2–3 times more expensive may last considerably longer, and therefore, be well worth the extra cost over the long run.
The type of mill also can affect the selection of grinding media. Ball Mills use very large media while Attritors employ media ranging in size from 1/8” to 1”. Horizontal mills require much smaller media, as small as 0.05 mm to 2 mm.
Our skilled technical service representatives also are available for consultation and are always ready to assist you with the selection of grinding media that best answer your particular needs. For assistance, contact Media Sales by calling (330) 929-3333 x228 or by .