
SiO2 ---------------------------------- 93-94%
Alumina(Al2O3) ------------------- 1.4 to 1.5%
Iron(Fe2O3) ------------------------ 1.5%-1.6%
Lime(CaO) -------------------------- 0.8% to 0.9%
Soda(Na2O) & Potash (Kro) -- 1.0% to 1.2%
Loss On Ignition(LOI) ----------- 1.0% to 1.2%
Magnesia(MgO) --------------------0.2 to 0.25%
They are highly resistant to acids, alkalis and thermal impact and their insolubility in acids and alkalis is about 97%














