ZIRCONIUM SILICATE (ZrSiO₄)

Introduction:
Zirconium Silicate (ZrSiO₄), commonly referred to as zircon or zircon powder, is a nesosilicate mineral. It is a premium material well known for its high whiteness after firing, extremely high melting point, and excellent resistance to abrasion and chemical attack. Zircon is the most important raw material for producing opaque white ceramic glazes.

1. Classification and Composition

No.	Component	Unit	Theoretical Content
1	Zirconium Oxide (ZrO₂)	%	~67.1%
2	Silicon Dioxide (SiO₂)	%	~32.9%
3	Impurities	%	HfO₂, Fe₂O₃, TiO₂ (very low in glaze grade)

• Application-based classification: Zircon is classified according to ZrO₂ content (typically 63–66%) and particle size (e.g., 325 mesh for casting; ultra-fine ≤ 5 µm for glazes).

2. Technical Specifications

Parameter	Value / Characteristics
Chemical formula	ZrSiO₄
Appearance	Fine to ultra-fine powder, off-white to light gray
Hardness (Mohs)	7.5–8 (very hard)
Melting point	Extremely high (~2550 °C)
Mechanical properties	High strength, toughness, and abrasion resistance
Thermal expansion	Low (excellent thermal stability)

3. Key Applications in Industry and Ceramics

Ceramic & Glaze Industry (Primary Application):
– Opacifying Agent: Zircon is the most effective opacifier for producing opaque white and light-colored ceramic glazes. Fine zircon crystals dispersed in the glaze scatter light, resulting in high whiteness and opacity.
– Enhanced Glaze Durability: Improves surface hardness and abrasion resistance of glazes (floor tiles, sanitary ware). Ceramics containing zircon can exhibit up to 15 times higher wear resistance compared to alumina-based ceramics.
Refractory Materials:
– Used in high-grade refractory bricks, kiln linings, and crucibles due to its very high melting point and excellent chemical corrosion resistance.
Foundry Industry:
– Used as zircon sand for molds and cores in metal casting. Zircon provides outstanding thermal resistance and chemical stability, producing smooth and precise cast surfaces.
Other Industries:
– A key raw material for producing zirconia (ZrO₂) ceramics, an advanced ceramic material with high strength and toughness, widely used in medical and aerospace applications.