Zircon (Foundry and Refractory Sand)

What zircon (Foundry and Refractory Sand) actually is

The species behind zircon (Foundry and Refractory Sand) is zirconium silicate recovered as a co-product of heavy mineral sand mining for titanium minerals; used for its refractoriness, low thermal expansion and opacity, ZrSiO4, with 1-2% HfO2 and trace U and Th; it forms in the tetragonal system.

Colourless to pale brown; whiteness and low iron matter for opacifier grades is responsible for the colour — and the chromophore, not the name, is what decides whether a colour is stable.

On the instruments it reads a refractive index of 1.92-2.01 and a specific gravity of about 4.60-4.70, with imperfect; often metamict where uranium content is high cleavage.

Where zircon (Foundry and Refractory Sand) comes from

Commercial material comes from Eneabba, Jacinth-Ambrosia and Murray Basin, Australia - the largest producing region, Richards Bay, KwaZulu-Natal, South Africa, Moma, Nampula Province, Mozambique and Kwale, Kenya; Senegal; Florida and Georgia, USA.

Different localities give different colour and different clarity, and the trade prices them differently. We state which one.

How zircon (Foundry and Refractory Sand) is treated

Wet and dry gravity, magnetic and electrostatic separation; milled to flour for opacifier grades. Uses: ceramic tile and sanitaryware opacifier (the largest single use), foundry sand and core wash for steel casting, refractory bricks for glass furnaces, TV and optical glass, and as the feedstock for zirconia and zirconium metal. RADIOLOGICAL: zircon contains uranium and thorium at levels that make it a NORM (naturally occurring radioactive material) - milling zircon flour is regulated in the EU and elsewhere, workers are monitored, and some jurisdictions cap activity concentration in consumer ceramics. Supply is tied to titanium feedstock demand, not its own.

We state the treatment on every stone, including when the honest answer is that it cannot be determined. A treatment disclosed is a fact; a treatment discovered later is a refund.

What zircon (Foundry and Refractory Sand) is confused with

Watch for Chromite and olivine foundry sands, Synthetic zirconia and zircon flour, Alumina refractories and Cubic zirconia (a synthetic gem, made from zirconia, not this) — these are what turn up sold under this name.

The separation is rarely a matter of opinion: refractive index 1.92-2.01 and specific gravity 4.60-4.70 settle most of it in a minute, and magnification settles the rest.

What zircon (Foundry and Refractory Sand) is used for

The trades that buy zircon (Foundry and Refractory Sand) are heavy industry and abrasives. They do not want the same thing, and they do not pay in the same unit.

We quote each application in the unit that trade actually buys in, by the tonne.

Durability and care

Zircon (Foundry and Refractory Sand) is 7.5 on the Mohs scale, with imperfect; often metamict where uranium content is high cleavage.

Hardness is not the whole story. Perfect cleavage means the stone can split cleanly if struck along the wrong plane, whatever its Mohs number, so a protective setting matters more here than the hardness suggests.

Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.

What zircon (Foundry and Refractory Sand) costs

Expect roughly $1,400-2,300 per tonne for premium zircon sand; standard and intermediate grades below that, depending on quality.

That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.

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