Download the Grinding Media Literature (144 KB PDF)

Union Process can meet your grinding and dispersing requirements with a full line of the highest quality grinding media available. A detailed sheet which outlines factors to consider when selecting grinding media, along with specifications on the most common types of media is available at no charge.

How To Select Your Grinding Media
Union Process, Inc., innovator and custom-manufacturer of the ATTRITOR and DELTAMILL, meets all your grinding and dispersing requirements with a full line of the highest quality grinding media available. Selection of grinding media 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.

* pH-Some strong acid or basic slurries may react with certain metallic media.

* Discoloration-Certain media result in color development and are, therefore, not suitable in the production of some materials such as white coatings.

* Contamination-Material resulting from the wear of the media affect the product and may need to be removed by a magnetic separator, chemicals, or a sintering process.

* 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.

Our skilled technical service representatives are always available for consultation and ready to assist you with the selection of media that best answers your particular needs.

GRINDING MEDIA SPECIFICATIONS (Ordered by Specific Gravity)
Sizes shown in red indicate media that is recommended for use in small media mills.

Through-Hardened Steel Shot
Sizes Available: 0.25mm, 0.50mm, 0.65mm, 0.80mm, 1.00mm, 1.50mm
Specific Gravity: 7.8
Hardness: ROCKWELL C 40 – 50
Cost: Low

Zirconium Silicate
Sizes Available: 0.1 – 0.2mm, 0.2 – 0.3mm, 0.3 – 0.4mm, 0.4 – 0.6mm, 0.6 – 0.8mm, 0.8 – 1.0mm, 1.0 – 1.25mm, 1.25 – 1.6mm, 1.6 – 2.0mm
2.0 – 2.5mm, 2.5 – 2.8mm
Specific Gravity: 3.85
Hardness: MOHS 7.0
Cost: Moderate

High Purity Zirconium Oxide (Y203 stabilized)
Sizes Available: 93% 0.7 – 0.9mm, 0.9 – 1.1mm, 1.1 – 1.3mm, 1.3 – 1.5mm, 1.5 – 1.9mm, 1.9 – 2.5mm
95% 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.65mm, 0.8mm, 1mm, 1.25mm, 1.5mm, 1.75mm
95% 2mm, 3mm, 5mm, 6mm, 8mm, 10mm, 15mm, 20mm, 25mm
Specific Gravity: 6.0
Hardness: Hv 1280 kg/mm2
Cost: 93% Moderate, 95% High

Flint Stones
Sizes Available: 15 – 25mm
Specific Gravity: 2.6
Hardness: MOHS 7.5 – 8.0
Cost: Low

Alumina
Sizes Available: 90% 3mm, 7/32”, 1/4”, 3/8”, 1/2”
94% 2mm, 3mm, 5mm, 10mm, 15mm
96% 1/4”, 1/2”
99% 3/16”, 1/4”
99.5% 2mm, 3mm, 5mm, 10mm, 15mm
99.9% 3mm, 5mm, 10mm
Specific Gravity: 90% – 99.5% 3.4 – 3.7, 99.9% 3.9
Hardness: 90% ROCKWELL 45N 75, 94% Hv 1200 kg/mm2, 96% Hv 1400 kg/mm2, 99% ROCKWELL 45N 78-79, 99.5% Hv 1350 kg/mm2, 99.9% Hv 1750 kg/mm2
Cost: 90% Low, 94% Low to Moderate, 96% Low to Moderate, 99% Moderate, 99.5% Moderate, 99.9% High

Silicon Nitride
Sizes Available: 2mm, 3mm, 5mm, 10mm
Specific Gravity: 3.2
Hardness: Hv 1400 – 1500 kg/mm2
Cost: High

Mullite
Sizes Available: 1/16”, 1/8”
Specific Gravity: 2.8
Hardness: ROCKWELL 45N 70
Cost: Low

Zirconium Oxide (rare earth-stabilized)
Sizes Available: 0.4 – 0.7mm, 0.7 – 1.2mm, 1.2 – 1.7mm, 1.7 – 2.4mm
2.4 – 2.8mm, 2.8 – 3.3mm, 3/16”, 1/4”, 5/16”
Specific Gravity: 6.1
Hardness: Hv 1100 kg/mm2
Cost: Moderate

Tungsten Carbide
Sizes Available: 3/16”, 1/4”
Specific Gravity: 14.4 – 14.8
Hardness: 88 – 89 HRA
Cost: Moderate to High

Ceramic (Steatite)
Sizes Available: 1/8”, 1/4”
Specific Gravity: 2.6 – 2.7
Hardness: ROCKWELL 45N 60 – 65
Cost: Low to Moderate

Chrome Steel (SAE 52100)
Sizes Available: 1/8”, 5/32”, 3/16”, 7/32”, 1/4”, 5/16”, 3/8”, 1/2”
Specific Gravity: 7.8
Hardness: ROCKWELL C 62 – 66
Cost: Low to Moderate

Glass Beads
Sizes Available: 0.4 – 0.6mm, 0.6 – 0.8mm, 0.8 – 1.0mm, 1.0 – 1.2mm, 1.1 – 1.3mm, 1.2 – 1.4mm, 1.4 – 1.6mm,
1.6 – 1.8mm, 1.8 – 2.0mm
2.0 – 2.4mm, 2.3 – 2.7mm, 2.8 – 3.2mm, 3.2 – 3.8mm, 3.7 – 4.3mm, 4.2 – 4.8mm, 4.7 – 5.3mm, 5.7 – 6.3mm,
6.7 – 7.3mm, 7.6 – 8.4mm, 8.6 – 9.4mm, 9.5 – 10.5mm, 10.5 – 11.5mm
Specific Gravity: 2.5
Hardness: KNOOP 515 kg/mm2
Cost: Low

Silicon Carbide
Sizes Available: 1/8”, 3/16”, 1/4”
Specific Gravity: 3.1
Hardness: KNOOP 2800 kg/mm2
Cost: High

Zirconium Oxide (MgO stabilized)
Sizes Available: 0.6 – .85mm, 0.85 – 1.18mm, 1.18 – 1.4mm, 1.4 – 1.7mm, 1.7 – 2.3mm
1/4”, 3/8”, 1/2”
Specific Gravity: 5.4
Hardness: Hv 900 – 1000 kg/mm2
Cost: Moderate

Stainless Steel (AISI 440-C)
Sizes Available: 1/8”, 5/32”, 3/16”, 7/32”, 5/16”, 1/4”, 3/8”, 1/2”, 3/4”
Specific Gravity: 7.7
Hardness: ROCKWELL C 55 – 64
Cost: Moderate

Carbon Steel (SAE 1013—case-hardened, SAE 1065—through-hardened)
Sizes Available: 1/8”, 3/16”, 1/4”, 5/16”, 3/8”, 1/2”
Specific Gravity: 7.8
Hardness: ROCKWELL C 60 – 62
Cost: Low

NOTE: Grinding media is sold on a per pound basis, but ATTRITORS and DELTAMILLS are loaded by volume. Therefore, the more dense the media, the more pounds of media required. For instance, a machine requiring only 40 lbs. of stainless steel may require up to 80 lbs. of tungsten carbide. Information contained herein is accurate and reliable to the best of our knowledge, but our suggestions and recommendations cannot be guaranteed because the conditions of use are beyond our control.

For more information, contact Media Sales.
Phone: (330) 929-3333
Fax: (330) 929-3034
E-mail: mediasales@unionprocess.com