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Acid Zirconium Sulphate Tetrahydrate (AZST)

CAS Number: 14644-61-2
Chemical formula: Zr(SO4)2.4H2O
Used in pigment coating and as a leather tanning agent

Acid Zirconium Sulphate Tetrahydrate (AZST) is used as a source of zirconium to coat TiO2 particles. This enables the surface of the particle to reflect rather than absorb UV light which reduces the yellowing effect of sunlight.

Colourless zirconium species as found in AZST are ideal for the tanning of white leathers.

Acid Zirconium Sulphate Tetrahydrate (AZST) is a white crystalline powder soluble in water.

Typical Chemical Analysis

ZrO2 + HfO2*      33% min
Fe2O3                    50 ppm max
TiO2                      100 ppm max
SiO2                      100 ppm max
NaO2                    500 ppm max

*HfO2 accounts for approximately 2wt% of this total.


25 kg bags
1000 kg bulk bags