Reaction mechanisms with water and other substances
The chemical reactivity of ferrosilicon is dependent on its composition and structural characteristics. The chemical reactivity of ferrosilicon in aqueous media is dependent on a number of factors, including temperature, pH and the presence of impurities in both the water and the alloy itself. In the presence of water, ferrosilicon undergoes a hydrolysis reaction under neutral or slightly acidic conditions.
This process results in the production of hydrogen gas (H₂) and silicic acid (H₄SiO₄). The reaction between FeSi and 4H2O produces Fe(OH)2, H2 and H4SiO4.
Silicic acid is a weak acid that can undergo further reactions with water molecules or other species present in solution. The release of hydrogen gas during hydrolysis presents a potential safety hazard due to the risk of fire. Furthermore, ferrosilicon displays reactivity towards specific acids, including sulfuric acid, at elevated temperatures. In these conditions, the reaction is exothermic, resulting in the release of hydrogen gas and the formation of corresponding metal sulphates. The reaction between FeSi and H2SO4 produces FeSO4, SiO2 and H2.
