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
SiO2 57,9 ± 5,0%
AL2O3 35,8 ± 2,0%
Fe2O3 1,5 ± 0,3%
CaO 1,1 ± 0,2%
MgO 1,6 ± 0,2%
SO2/SO3 0,6 ± 0,3%
K2O + Na2O 1,2 ± 0,4%
TiO2 0,8 ± 0,3%
Cl 0,2 ± 0,1%
Fly ash is used: In the production of lightweight concrete. Low-cement concrete is used in the preparation of road bases. Fly ash is also used in slag-silicate concretes, which are used to repair roads, airfields, bridges, as well as in the construction of acid-resistant floors in chemical plants, livestock farms, and metallurgical facilities. In the production of foam concrete, its introduction into the foam concrete mixture increases the aggregate stability of the mixture between the beginning and end of the cement dough setting, which prevents the movement of components and prevents negative effects on the formation of the structure. Fly ash easily replaces cement in the production of mortars, ready-mixed concrete, and finished products. It is used as an additive to cement without reducing its activity, is used in the preparation of concrete for road construction, and as an additive to clay in the manufacture of tiles and bricks. As a component of dry construction mixes: production of dry masonry mixes consisting of cement, sand, fly ash, ICP, and powdered superplasticizer.
