ANALYSIS OF THE STRUCTURAL-CHEMICAL MILL DUPLEX-SYSTEMS OF SILICATE-SILICIDE OF LUNG-EARTH METALS. Message 3. The mechanism of desulfurization in the smelting of blast-furnace pig iron

Abstract

The mechanism of cast iron desulfurization through structural and chemical reactions in smelting slags corresponding to the composition of the main mineral phases is presented: monticellite (MT, SiO2MgOCaO) → mervinite (MP, 2SiO2MgO3CaO) → ockermannite (OK, 2SiO2MgO2CaO) →diopside (DP, 2SiO2MgOCaO) → rankinite (pH, 2SiO23CaO) and eutectic slags (E, 3SiO2MgO4CaO). A sequential series of adsorption capacity of slag phases with respect to sulfur (АС, mas. %) and the depth of metal desulfurization – Δ(S), ppm was determined: Е (3.54/36) → MR (4.8/49) → OK (5, 7/59) → DP (7.14/74) → MT (9.8/103) → RN (20/222). In factory conditions, the efficiency of smelting slags of eutectic composition and diopside for ladle processing of cast iron was tested. The expediency of using such blast furnace slags for ladle processing of cast iron has been established, which at a consumption of 5-10 kg/t provide a desulfurization depth of 200-400 ppm. The consumption of slag is significantly reduced with the additional deoxidation of smelting slags with carbon during the release of melt in the ditch of the foundry and in the pig iron ladle.