The main chemical components in blast furnace slag are: silicon dioxide (SiO2), aluminum oxide (Al2O3), calcium oxide (CaO), magnesium oxide (MgO), manganese oxide (MnO), iron oxide (FeO) and sulfur, etc. . In addition, some slag also contains traces of titanium oxide (TiO2), alum oxide (V2O5), sodium oxide (Na2O), barium oxide (BaO), phosphorus pentoxide (P2O5), chromium trioxide (Cr2O3), etc. In blast furnace slag, calcium oxide (CaO), silicon dioxide (SiO2), aluminum oxide (Al2O3) account for more than 90% of the weight.
Various oxide components in blast furnace slag exist in various forms of silicate minerals.
The most common minerals in alkaline blast furnace slag are yellow feldspar, dicalcium silicate, olivine, wollastonite, wollastonite and spinel.
Acidic blast furnace slag has different minerals due to its different cooling rate. When rapidly cooled, all condense into a glass body; when slowly cooled (especially weak acidic blast furnace slag), crystalline mineral phases, such as yellow feldspar, pseudo wollastonite, pyroxene and plagioclase, etc. often appear.
Almost all of the mineral components of high-titanium blast furnace slag contain titanium.
Manganese olivine (2MnO · SiO2) and rose pyroxene (MnO · SiO2) minerals exist in the ferromanganese slag.
There are large amounts of calcium aluminate (CaO · Al2O3), pentacalcium trialuminate (5CaO · 3A12O3), calcium dialuminate (CaO · 2Al2O3), etc.