Kaopaque 20 Kaolin

Alternate Names: Kaopaque, Kaopaque Kaolin

Description: White Non Plastic Delaminated Kaolin

Oxide	Analysis	Formula
CaO	0.21%	0.01
K2O	0.08%	-
MgO	0.03%	-
Na2O	0.03%	-
TiO2	0.66%	0.02
Al2O3	39.30%	1.00
SiO2	45.20%	1.95
Fe2O3	0.32%	0.01
LOI	12.00%	n/a
Oxide Weight		222.76
Formula Weight		253.14

Notes

A white firing delaminated material of low plasticity. Kaopaque 20 and 10 are non-predispersed from a water-fractionated feed for a controlled particle size and shape (very large plate-like). It is refined from Geogia deposits. Kaopaque 10S is the pre-dispersed version and is supplied as a lightly pulverized spray-dried powder and as a slurry. The large plate-like particles of Kaopaque 10 have a thickness of 0.2 to 0.4 microns and a diameter of 2 to 10 microns.

Kaopaque is useful in casting porcelains. It fires white compared to other North American kaolins (because of its low Fe₂O₃ and TiO2), but others available internationally are much whiter (e.g. New Zealand halloysite, Grolleg kaolin, they have higher Fe₂O₃ but their TiO2 levels are more than ten times lower). Kaolins of higher iron content, like Opticast, also work well for slip casting and cost much less.

Kaopaque 20 has very high fired shrinkage (from 10-12% from cone 8-10), happening inspite of the fact that it is very refractory (15% porosity at cone 8, 10% at cone 10).

Related Information

Links

URLs	http://www.fitzchem.com/ More information
Materials	Kaolin The purest of all clays in nature. Kaolins are used in porcelains and stonewares to impart whiteness, in glazes to supply Al2O3 and to suspend slurries.
Typecodes	Kaolin Pure clay mineral, there are many brand names of varying purity and iron content.

By Tony Hansen
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