Property       

Typical Value

SiO2

> 95.0 %

Fe2O3

< 0.8 %

Al2O3

< 0.6 %

CaO

2.0 – 3.0 %

TiO2

<0.2 %

Na2O+K2O

<0.35%

Apparent porosity (%)

≤22

Cold crushing strength (MPa)

30–75 for pressed shapes

25 – 75 for hand-rammed shapes

Residual quartz

<1.0 %

Refractoriness under load 0.2MPa (ºC)

≥1680

Thermal expansion (%) from 25 – 1500ºC in steps of no more  than 25ºC

Maximum 1.4%