Product

The microspheres are a waste material arising in the process of combustion of hard coal. The product is made of spheres with a diameter of 10-800 microns, filled with gas, mostly CO₂ and NO₂. Sheaths of the spheres are 0.2-3 microns thick, what makes the microspheres have a great volume at a relatively low gravity. Material contains mainly: silicon oxide (SiO₂), aluminum oxide (Al2O3), magnesium oxide (MgO), iron trioxide (Fe₂O₃), potassium oxide (K₂O), calcium oxide (CaO) and vestigial admixtures of other metals.

Chemical Composition

Vestigial elements / Maximal values in ppm:

Granulation

Roasting losses

Physical characteristics

• colour light grey
• embankment weight in dry condition 400 ± 30 [kg/m³]
• sheaths weight 2200 ± 200 [kg/m³]
• relative density 690 ± 50 [kg/m³]
• hardness in Mohs’ scale 6 ± 1
• thermal conductivity 0,07 ± 0,03 [W/m²K]
• aqueous extract’s pH factor 7 ± 1
• melting temperature 1495 ± 10 [°C]
• softening temperature 1220 ± 10 [°C]
• sheaths’ internal pressure 0,2 ± 0,1 [bar]
• waste parts max. 5 %
• water content in a dry product < 0,5 %