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Ceramic Dispersion and Milling Media

Based Upon Zirconium Oxide

Engineered for uniform size and shape, Zirbeads are extremely hard, non-porous, resist chipping and fractures and are exceptionally smooth, delivering the high shear and intense impact today’s heavy-duty continuous mills demand. Zirbeads can disperse and grind pre-mixes up to 50,000 cps, including: inks, automotive and magnetic coatings, more efficiently than Zircon or Alumina beads, with less contamination.

Formulations up to 50,000 cps and particle sizes less than 1µm are routinely processed and achieved with very low media and mill wear.

Today’s mills operate with media occupying up to 90%, or more, of the void volume. Zirbeads’ higher density allows for a smaller diameter bead, resulting in more beads per charge, and providing more contact points for the product during residence. Using Zirbeads can double the number of beads per unit of weight.

High viscosity and high percent solid formulations, such as automotive coatings and inks, are the ideal pre-mixes for Zirbeads. The characteristically higher mass of Zirbeads provides the greater power (kinetic energy) needed by formulations of this nature. Zirbeads by Zircoa can disperse and grind pre-mixes up to 50,000 cps.

A Unique Material

Zirbeads are made of zirconia... a unique material, and the most dense ceramic media available. Zirbeads are hard, uniform in size and shape, non-porous, and exceptionally smooth. They resist chipping and fractures, extending the life of the media and the mill, and minimizing batch contamination. Chemically inert, Zirbeads are resistant to virtually all acids and alkali, and are non-conductive and non-magnetic.

Zirbeads Selection

Zircoa has developed two Zirbead grades for most pre-mix formulations and mill requirements.

Zirbeads Super (1.4 to 3.35 mm) SUPER (1.4 to 3.35 mm) — When you require media with a wider and more economical distribution ... SUPER is the right choice. Historically used in vertical mills, Zirbeads SUPER now has several horizontal mill applications.Zirbeads Super "XR" (.6 mm)

SUPER "XR" (.6 to 2.3 mm) — Designed for today’s modern horizontal mills, Zirbeads SUPER "XR”" provides the narrow size distribution needed for inks, automotive and magnetic coatings.Zirbeads Super "XR" (2.3 mm)


Optimizing Mill Performance with Zirbeads

To achieve optimum performance, Zirbeads contact with the formulation must be maximized. To achieve this, the agitation speed, Zirbead size, and throughput, must be balanced to the viscosity of the formulation. A donut-flow pattern of Zirbeads inside the mill is an indication of proper balance.

Zirbeads are designed for a formulation viscosity no less than 1000 cps, although milling of lower viscosity formulas is possible. As the viscosity drops, the balance between speed and bead size becomes more critical, to avoid excessive wear on the mill and the media itself. If you hear splashing, the viscosity is too low.

Introduce pre-mix that is sufficiently fine and homogeneous, then start the mill. Zirbeads unsupported by pre-mix can cause start-up and wear problems. Make sure the discharge screen is properly matched to the Zirbead size.

Never mix Zirbeads with other media. Zirbeads will grind-up lower density media such as zircon and glass beads, contaminating the product and causing undue wear on the mill.

  1. The wear rate of Zirbeads is one half to one third that of other dispersion media. See "Typical Properties"
  2. A 21% reduction in diameter allows twice as many beads. See "Suggested Charge Weights"

Suggested Media Charge Weights for Zirbeads

Horizontal Mill Size
(Void Volume)
Zirbeads Super XR
for 85%
(1mm) Charge
liters lbs. kg
15 102 46
20 136 62
45 305 139
100 677 308
200 1355 616


Available Sizes - Zirbeads

Media Sizes Nom.
Range (mm) Tyler Mesh
1.4 - 3.35
1.4 - 2.36
-6 +12
-8 +12
Super XR
1.7 - 2.3
1.4 - 1.7
.85 - 1.18
.6 - .85
  -8 +10
-10 +12
-14 +20
-20 +28

NOTE: Other sizes available upon request.

Typical Properties Comparison - Zirbeads

lb./grain (a)
Rating (b)
Zirbeads 5.5 ZrO2 (c) 125 to 220 7
Zircon beads 3.7 ZrO2•SiO2 105 to 160 11
Alumina beads 3.5 Al2O3 125 to 220 22
Glass beads 2.8 SiO2 40 to 70 (d)
Ottawa sand 2.8 SiO2 10 to 20 (d)

(a) ASTM D 1213-54
(b) Zircoa Zirbeads wear test No. 59531. Zero = no wear.
(c) Typical composition (wt. %): ZrO2 97, MgO 3, SiO2 <.35, CaO<.5, Fe2O3 <.1, Al2O3 <.2, TiO2 <.1
(d) Specific gravity too low for test conditions