Physicochemical indicators:

SiO 2 (> 70%), thermal conductivity (W/m.K), heat surface 200 (> 0.025), heat surface 500 (= 0.035), heat surface 800 (= 0.040),

Volume density (Kg/m3) 400-600 compressive strength > 2.0 MPa, using temperature < 1000 C.