Christy Red Plastic Fireclay

Oxide	Analysis	Formula
SiO2	50.20%	3.13
Al2O3	27.20%	1.00
Fe2O3	5.10%	0.12
TiO2	1.30%	0.06
K2O	2.90%	0.12
MgO	1.00%	0.09
CaO	0.50%	0.03
Na2O	0.10%	0.01
P2O5	0.30%	0.01
LOI	11.00%	n/a
Oxide Weight		332.25
Formula Weight		373.31

Notes

According to the data sheet it fires red progressing to brown by 2200F and purple/brown by 2400F.
The data sheet from Christy Minerals is unclear since it lists separate drying shrinkages for each of four temperatures (1800, 2000, 2200, 2400F) and they vary from 4.5 to 8.5% (this is not firing related, only one number should be stated).

Also, the LOI shown on the chart averages about 7% but in the analysis is 11%.
This material has an uncharacteristic fired shrinkage reduction with increasing temperature (12% at cone 08 going down to 3% by cone 9). This is happening because the material is beginning to expand already by 1900F and starting to bloat by 2200F.

Particle size (this is a 35 mesh material)
Retained: US 40: 22%
Retained: US 70 26.7%
Retained: US 200 28.5%

Related Information

Links

Typecodes	Fireclay Fireclays are non-kaolin non-ball clay materials similar to stoneware clays but lacking fluxing oxides. Many fireclays have a PCE of 28 or more.

By Tony Hansen
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