Grinding Media
Grinding media are the means used to crush or grind material in a mill. It comes in different forms such as alumina oxide balls, ceramic cylinders, or soda lime glass. At Norstone Inc., we offer all types of medias used for grinding, deagglomeration, polishing, deburring, fillers, proppants, spacers, refractory beds and shot peening. Below, you’ll find a variety of ceramic grinding media specifically formulated to ensure reliable, consistent performance for your bulk material preparation. We also offer technical expertise on current and expanded uses for these medias; Call us to ensure that you are using the right media for your current product and process! Our specialists will recommend the best suited media, shape, size and alloy. The choice of media can depend upon the material to be ground, the grinding process, and the wear mechanisms involved. Toll/Screening services are available for sizing worn media.

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12% chrome balls
12% Chrome Balls
Polyamide
Polyamide Cubes or Cylinders, 1.05 gm/cc
Polystyrene
Polystyrene Spheres, 1.05 gm/cc
pmma
PMMA Spheres, 1.05 gm/cc
Nylon Balls
Nylon Balls, 1.13 gm/cc
Polyurethane
Polyurethane Balls With or Without Steel Cores, 1.20 gm/cc
Polycarbonate
Polycarbonate Cylinders, 1.20 gm/cc
Colored Polyurethane Balls
Colored Polyurethane Balls, 1.20 gm/cc
Sand
Sand, 2.50 gm/cc
Soda Lime Glass
Soda Lime Glass, 2.50 gm/cc
Molded Soda Lime Glass
Molded Soda Lime Glass, 2.50 gm/cc
Low Alkali Boro Glass
Low Alkali Boro Glass, 2.60 gm/cc
Flint Pebbles
Flint Pebbles, 2.60 gm/cc
Steatite Satellites
Steatite, 2.60 gm/cc
Alumina Balls
Alumina Balls, 2.70-3.60 gm/cc
Alumina Satellites
Alumina Satellites, 2.70-3.60 gm/cc
Alumina Cylinders
Alumina Cylinders, 2.70-3.60 gm/cc
Alumina Naturals
Alumina Naturals, 3.60 gm/cc
Alumina Beads
Standard Alumina/70%-92%, 2.70-3.60 gm/cc
High Purity Alumina
High Purity Alumina/94%-99.999%, 3.70-3.80 gm/cc
Silicon Carbide Beads
Silicon Carbide Balls, 2.90/3.20 gm/cc
Silicon Carbide Satellites
Silicon Carbide Satellites, 2.90/3.20 gm/cc
Silicon Nitride
Silicon Nitride Balls, 3.20-3.30 gm/cc
mullite_lrg
Mullite/45%-70%, 3.25 gm/cc
Zirconia Silica
Fused Zirconia Silica, 3.80 gm/cc
Zirconia Silicate
Sintered Zirconia Silicate, 4.00 gm/cc
Zirconia Toughened Alumina
ZirTA-NOR (Zirconia Toughened Alumina), 4.20 gm/cc
High Density ZirSil
High Density Zirconia Silica, ZirSil-HD, 4.60 gm/cc
Magnesium Zirconia Oxide Beads
Magnesium Zirconia Oxide Beads, 5.50 gm/cc
Magnesium Zirconia Oxide Satellites
Magnesium Zirconia Oxide Satellites, 5.50 gm/cc
Magnesium Zirconia Oxide Cylinders
Magnesium Zirconia Oxide Cylinders, 5.50 gm/cc
Cerium Zirconia Oxide Satellites
Cerium Zirconia Oxide Satellites, 6.00/6.25 gm/cc
Cerium Zirconia Oxide Beads
Golden Brown Cerium Zirconia Oxide Beads, 6.20 gm/cc
Black Cerium Zirconia Oxide
Black Cerium Zirconia Oxide Beads, 6.25 gm/cc
CeNOR Beads
Dark Brown Cerium Zirconia Oxide Beads, 6.25 gm/cc
Cerium Zirconia Oxide Cylinders
Cerium Zirconia Oxide Cylinders, 6.00/6.25 gm/cc
High Quality Yttria Zirconia Oxide Beads
High Quality Yttria Zirconia Oxide Beads, 6.00 gm/cc
Highest Quality Yttria Zirconia Oxide Beads
Highest Quality Yttria Zirconia Oxide Beads, 6.00 gm/cc
Yttria Zirconia Oxide Cylinders
Yttria Zirconia Oxide Cylinders, 6.00 gm/cc
Carbon Steel Balls
Carbon Steel Balls, 7.60 gm/cc
Chrome Balls
Chrome Alloy Balls 52100, 7.60 gm/cc
Chrome Diagonals
Chrome Diagonals, 7.60 gm/cc
Cold Headed Steel Balls
Cold Headed Steel Balls, 7.60 gm/cc
Stainless Steel Balls
Stainless Steel Balls, 7.60 gm/cc
Conditioned Cut Wire
Stainless Steel Conditioned Cut Wire, 7.60 gm/cc
Stainless Steel Cut Wire
Stainless Steel Cut Wire, 7.60 gm/cc
GE DIGITAL CAMERA
Stainless Steel Cylinders, 7.60 gm/cc
Stainless Steel Jewelry Mix
Stainless Steel Jewelry Mix, 7.60 gm/cc
Stainless Steel Shot
Stainless Steel Shot, 7.60 gm/cc
Steel Shot
Steel Shot, 7.60 gm/cc
Tungsten Carbide Beads
Tungsten Carbide Beads, 15.00 gm/cc
Tungsten Carbide Satellites
Tungsten Carbide Satellites, 15.00 gm/cc

12% chrome balls

Polyamide

Non-abrasive, cube shape, high chemical resistance, non-toxic, dust free. Smallest size available is 0.5mm x 0.5mm x 0.87mm diagonal. Density: 1.20 gm/cc. Bulk Density: 0.68 kg/l; 1.50 #/l; 2.50 kg/gal; 5.50 #/gal

Polystyrene

Non-abrasive, spherical in shape, non-toxic and dust free. A variety of levels of cross linked polymers are available in sizes as small as 100 microns. Low in density but tough and wear resistant. Standard and Toughened Polystyrene beads have a strong odor from free styrene but this can be eliminated with a warm water wash. Also available in food grade, porous, toughened and narrow particle distributions. Density: 1.05 gm/cc. Bulk Density: 0.63 kg/l; 1.40 #/l; 2.30 kg/gal; 5.00 #/gal

pmma

Non-abrasive, spherical in shape, non-toxic, no odor and dust free. Available in sizes under 150 microns. Not solvent resistant. Density: 1.05 gm/cc. Bulk Density: 0.63 kg/l; 1.40 #/l; 2.30 kg/gal; 5.00 #/gal

Nylon Balls

Smallest size available is 2.0 mm.  Good solvent resistance.  Can swell with use in water.  Nylon also stains if used with pigments. Density: 1.13 gm/cc. Bulk Density: 0.68 kg/l; 1.50 #/l; 2.50 kg/gal; 5.50 #/gal

Polyurethane

High density, non-toxic balls used for delumping, mixing and blending of powders. Certain sizes are available with steel cores. Very long wearing and gentle on the mill. Density: 1.20 gm/cc. Bulk Density: 0.72 kg/l; 1.60 #/l; 2.60 kg/gal; 5.80 #/gal.

Polycarbonate

High density, non-toxic, cylinder shape, dust free. Smallest size is 0.5mm x 0.71mm. Density: 1.20 gm/cc. Bulk Density: 0.72 kg/l; 1.60 #/l; 2.60 kg/gal; 5.80 #/gal

Colored Polyurethane Balls

High density, non-toxic balls used for delumping, mixing and blending of powders. Certain sizes are available with steel cores. Very long wearing and gentle on the mill. Density: 1.20 gm/cc. Bulk Density: 0.72 kg/l; 1.60 #/l; 2.60 kg/gal; 5.80 #/gal.

Sand

This media is still used because of its low price but can be costly in the long run. It is abrasive to the mill due to its irregular shape as it is more needle-like than spherical and the tips tend to break off. Waste disposal of this short term media can also be expensive. Alternative medias are glass and mullite. Density: 2.50 gm/cc. Bulk Density: 1.50 kg/l; 3.30 #/l; 5.50 kg/gal; 120 #/gal

Soda Lime Glass

This is the most popular glass sphere used for grinding media. The larger beads are molded. Some brands are produced from virgin glass while others are produced from recycled glass. Air inclusions also vary which can determine the life span of the bead as it determines the strength of the bead. This is an excellent bead for low viscosity material or low heat processes. Density 2.50 gm/cc. Bulk Density: 1.50 kg/l; 3.30 #/l.; 5.50 kg/gal; 12.00 #/gal

Molded Soda Lime Glass

This is the most popular glass sphere used for grinding media. The larger beads are molded. Some brands are produced from virgin glass while others are produced from recycled glass. Air inclusions also vary which can determine the life span of the bead as it determines the strength of the bead. This is an excellent bead for low viscosity material or low heat processes. Density 2.50 gm/cc. Bulk Density: 1.50 kg/l; 3.30 #/l.; 5.50 kg/gal; 12.00 #/gal

Low Alkali Boro Glass

There are several grades of borosilicate glass beads. This bead is used for low alkali applications as well as food and pharmaceutical. There is also a high crush strength bead which is more abrasion resistant than the soda lime glass. It is more expensive than the soda lime but the value is there. Density 2.60 gm/cc. Bulk Density: 1.60 kg/l; 3.50 #/l.; 6.00 kg/gal; 13.30 #/gal

Borosilicate glass (PYREX grade) is also available.

Flint Pebbles

A natural resource that is getting harder to find in its natural state. It is basically quartz having similar density to glass but harder with irregular shapes and surfaces. The benefit of the pebble is the aspect ratio thus giving it a lot of surface area for contact in the mill. They are still available but getting to be expensive. A good alternative is Steatite. Density: 2.60 gm/cc. Bulk Density: 1.60 kg/l; 3.50 #/l; 6.00 kg/gal; 13.30 #/gal

Steatite Satellites

This media is a fused magnesium silicate composite made up of 62% SiO2. The minimum size is 6.0 mm available in satellite balls, cylinders and spheres. This is an excellent alternative to flint pebbles or large glass balls. It lasts longer than glass but is the same density. Density 2.60 gm/cc. Bulk Density: 1.60 kg/l; 3.50 #/l; 6.00 kg/gal; 13.30 #/gal

Alumina Balls

Generally available in 92% and higher, balls tend to have less wear issues than satellites. Balls & satellites are much easier to use than cylinders and are commonly found in liquid grinding applications. Density: 3.60 gm/cc. Bulk Density: 2.20 kg/l; 4.90 #/l; 8.20 kg/gal; 18.00 #/gal

Alumina Satellites

Available in percentages of 92% and lower. They are easier to use than cylinders and one of the most popular medias for ball milling. Density: 3.60 gm/cc. Bulk Density: 2.20 kg/l; 4.90 #/l; 8.20 kg/gal; 18.00 #/gal

Alumina Cylinders

Available in the same alumina percentages as balls and satellites but larger sizes are more limited in options. Cylinders are used for both liquid and powder processing when fines are needed. They can also be susceptible to chipping around the edges. Density: 3.60 gm/cc. Bulk Density: 2.20 kg/l; 4.90 #/l; 8.20 kg/gal; 18.00 #/gal

Alumina Naturals

Designed to mimic the surface area of flint pebbles.  These are 90% alumina and available in only two sizes.  Density: 3.60 gm/cc. Bulk Density: 2.20 kg/l; 4.90 #/l; 8.20 kg/gal; 18.00 #/gal

Alumina Beads

This is still the most common range of alumina media used for particle size reduction in both powder and liquid grinding. Beads are available as well as balls, satellites and cylinders. Some sizes are available in both dry pressed and iso pressed. The beads can be abrasive. Density: 3.60 gm/cc. Bulk Density: 2.20 kg/l; 4.90 #/l; 8.20 kg/gal; 19.00 #/gal.

High Purity Alumina

Alumina with this higher purity is used in grinding materials which cannot tolerate contamination other than alumina. It can be dramatically more expensive and is also more brittle than other alumina formulations. It is available in spheres, satellites and cylinders. Density: 3.80 gm/cc. Bulk Density: 2.40 kg/l; 5.30 #/l; 8.60 kg/gal; 19.00 #/gal.

Silicon Carbide Beads

This is a low density ceramic available in limited sizes. The balls and satellites are usually custom made.  It is very expensive but used where limited contamination is required. Density: 2.90/3.20 gm/cc.

Silicon Carbide Satellites

This is a low density ceramic available in limited sizes. The balls and satellites are usually custom made.  It is very expensive but used where limited contamination is required. Density: 2.90/3.20 gm/cc.

Silicon Nitride

This is considered an exotic media and is available in beads, spheres and grit.  Minimum size is 3.0 mm but will soon be replaced by 5.0 mm. Density: 3.20-3.30 gm/cc

mullite_lrg

This alumina media is most often referred to as MULLITE with approximately 35% SiO2. It has the advantage of being higher in density than glass and lower density than other aluminas. Beads are available in several different alumina concentrations and densities, with or without bauxite. It is available in small beads, satellites and cylinders. It lasts longer than glass and is not as abrasive as other aluminas. Density: 3.25 gm/cc. Bulk Density: 1.74 kg/l; 3.80 #/l; 6.70 kg/gal; 14.50 #/gal

Zirconia Silica

This bead is also a popular medium density bead which looks almost identical to the Zirconia Silicate but they can NEVER be mixed. This bead is FUSED and is consistent from the crust to the core. It lasts longer than a sintered bead but should not be used in sizes above 2.0 mm because of the inherent air inclusions known as hollows in the bead. This bead can crack and break and cause abrasion problems in the mill. Preconditioning the beads is strongly recommended. Density: 3.80 gm/cc. Bulk Density: 2.40 kg/l; 5.00 #/l; 8.60 kg/gal; 19.00 #/gal

Zirconia Silicate

This is a popular, medium density, bead which is SINTERED. This bead has a hard outer crust and a soft inner core so it should be used in less aggressive types of small media mills. Sizes above 3.0 mm are not practical because of the inherent structure which weakens the bead and causes it to crack and break. This bead can be abrasive to the mill. Density: 4.00 gm/cc. Bulk Density: 2.45 kg/l; 5.30 #/l; 9.27 kg/gal; 20.40 #/gal.

Zirconia Toughened Alumina

Zirconia Toughened Alumina: This product is relatively new and has proven to be an excellent media in the medium density range. It is solid, white, round, has high fracture resistance with lower amounts of zirconia and no radioactivity. Sizes start at 0.6 mm and can be made up to 2″ in balls and cylinders. Density: 4.20 gm/cc Bulk Density: 2.60 kg/l; 5.70 #/l; 9.60 kg/gal; 21.00 #/gal.

High Density ZirSil

This is a relatively new bead which is a FUSED zirconia silica containing a higher amount of zirconia than the more common formulation. Customers have been impressed with its ability to last much longer than standard zirconia silica and silicate, its lower wear on the equipment and faster grinds.  Density: 4.60 gm/cc. Bulk Density: 2.80 kg/l; 10.60 kg/gal; 23.30 #/gal; 6.20 #/l.

Magnesium Zirconia Oxide Beads

A very popular high density ceramic satellite or cylinder for all types of milling. While this form of the media is excellent, the bead is very poor in that it is abrasive to both the mill and itself. Density: 5.50 gm/cc. Bulk Density: 3.20 kg/l; 7.00 #/l; 11.80 kg/gal; 26.00 #/gal

Magnesium Zirconia Oxide Satellites

A very popular high density ceramic satellite or cylinder for all types of milling. While this form of the media is excellent, the bead is very poor in that it is abrasive to both the mill and itself. Density: 5.50 gm/cc. Bulk Density: 3.20 kg/l; 7.00 #/l; 11.80 kg/gal; 26.00 #/gal

Magnesium Zirconia Oxide Cylinders

A very popular high density ceramic satellite or cylinder for all types of milling. While this form of the media is excellent, the bead is very poor in that it is abrasive to both the mill and itself. Density: 5.50 gm/cc. Bulk Density: 3.20 kg/l; 7.00 #/l; 11.80 kg/gal; 26.00 #/gal

Cerium Zirconia Oxide Satellites

This is a relatively new high density media that has grown in popularity due to its durability and value pricing. The bead will not crack or break unless the mill was not put together properly. The media is available in beads, satellites, cylinders and spheres. Density: 6.00/6.25 gm/cc. Bulk Density: 3.60/4.00 kg/l; 7.90/8.80 #/l; 12.70/15.10 kg/gal; 28.00/33.00 #/gal

Cerium Zirconia Oxide Beads

This is a relatively new high density media that has grown in popularity due to its durability and value pricing. The bead will not crack or break unless the mill was not put together properly. The media is available in beads, satellites, cylinders and spheres. Density: 6.20 gm/cc. Bulk Density: 3.60/4.00 kg/l; 7.90/8.80 #/l; 12.70/15.10 kg/gal; 28.00/33.00 #/gal

Black Cerium Zirconia Oxide

CeNOR Beads

Cerium Zirconia Oxide Cylinders

This is a relatively new high density media that has grown in popularity due to its durability and value pricing. The bead will not crack or break unless the mill was not put together properly. The media is available in beads, satellites, cylinders and spheres. Density: 6.00/6.25 gm/cc. Bulk Density: 3.60/4.00 kg/l; 7.90/8.80 #/l; 12.70/15.10 kg/gal; 28.00/33.00 #/gal

High Quality Yttria Zirconia Oxide Beads

This is the highest, longest lasting and toughest high density media. This media is very hard and non-porous so that it will not break or crack, cleans easily, and is available in several grades. Beads, spheres and cylinders are available in a wide range of sizes. Density: 6.00 gm/cc. Bulk Density: 3.70 kg/l; 8.10 #/l; 14.00 kg/gal; 30.10 #/gal

Highest Quality Yttria Zirconia Oxide Beads

This is the highest, longest lasting and toughest high density media. This media is very hard and non-porous so that it will not break or crack, cleans easily, and is available in several grades. Beads, spheres and cylinders are available in a wide range of sizes. Density: 6.00 gm/cc. Bulk Density: 3.70 kg/l; 8.10 #/l; 14.00 kg/gal; 30.10 #/gal

Yttria Zirconia Oxide Cylinders

This is the highest, longest lasting and toughest high density media. This media is very hard and non-porous so that it will not break or crack, cleans easily, and is available in several grades. Beads, spheres and cylinders are available in a wide range of sizes. Density: 6.00 gm/cc. Bulk Density: 3.70 kg/l; 8.10 #/l; 14.00 kg/gal; 30.10 #/gal

Carbon Steel Balls

Case and through hardened steel balls which can rust.  They are available in a wide range of alloys and sizes as large as 8" diameters. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Chrome Balls

This is a through hardened chrome alloy steel ball. It is highly polished and mono-sized with a hardness of 63-65 Rockwell C. The pricing is reasonable for an almost ball bearing quality media. It is slow to rust and is a long lasting steel media. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Chrome Diagonals

These are used in a variety of grinding and polishing operations, very slow to rust. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Cold Headed Steel Balls

Through hardened carbon steel balls that have a flat 180 degrees apart.  They are commonly used in steel ball mills starting at 1/2" diameter.  They can rust. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Stainless Steel Balls

Through hardened balls which are available in various types of stainless. These balls can be expensive but generally used when other types are not acceptable. Stainless steel is softer than other forms of steel.  It can also work harden and become brittle. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Conditioned Cut Wire

Stainless Steel Cut Wire

This is cut wire which can then be used as cylinders or conditioned so that it is somewhat round in shape. It is available in various types of stainless.  Stainless steel is softer than other forms of steel.  It can also work harden and become brittle. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

GE DIGITAL CAMERA

Not typically a popular media but still available. Stainless steel is softer than other forms of steel.  It can also work harden and become brittle.  Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Stainless Steel Jewelry Mix

These are used in a variety of grinding and polishing operations. They are softer than chrome steel. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Stainless Steel Shot

Steel Shot

There are many sources for steel shot but all are not equal since much of the steel shot is used for shot peening. Make sure that the shot is designed as a grinding media or it could tear up the mill. Steel shot is one of the least expensive grinding medias with the benefit of high density and the availability of a wide range of sizes for small media. The more narrow size ranges of shot will last longer. Density: 7.60 gm/cc. Bulk Density: 4.50 kg/l; 9.90 #/l; 17.80 kg/gal; 38.00 #/gal

Tungsten Carbide Beads

This media continues to grow in interest due to its high density. Beads and satellites are available in limited sizes. The mills using this media must be built to handle the high density. Density: 15.00 gm/cc. Bulk Density: 8.20 kg/l; 18.00 #/l; 30.00 kg/gal; 66.00 #/gal

Tungsten Carbide Satellites

This media continues to grow in interest due to its high density. Beads and satellites are available in limited sizes. The mills using this media must be built to handle the high density. Density: 15.00 gm/cc. Bulk Density: 8.20 kg/l; 18.00 #/l; 30.00 kg/gal; 66.00 #/gal