Super High Cleaning of Steel and Miniaturization of Inclusions by Deoxidation of Molten Iron with Magnesium Vapor In Situ Produced

点击翻译按钮获取中文摘要

Desulfurization and deoxidation of molten iron with magnesium vapor produced in situ by aluminothermic reduction of magnesium oxide were studied by combining high temperature and water model experiments. Removal and miniaturization results and formation mechanism of deoxidation product MgO were investigated. Furthermore, resulfurization in desulfurization process with Mg vapor and mechanism of aluminothermic reduction of MgO were also studied.1. High temperature experiment of deoxidation of molten steel with Mg vapor was conducted. Behavior of deoxidation product was studied. The inclusions formed after present dioxidation process was in spherical shape with a diameter of only about 1μm. Most of the deoxidation products were removed by rising Ar+Mg bubbles. The effects of various operating parameters on deoxidation rate and inclusion behavior were clarified. The composition and distribution of inclusion in steel were made clear by observation and analysis of inclusions remained in the … More steel.2. The combining deoxidation of molten steel with Al and in situ, produced Mg vapor was carried out. Most of the inclusions had the composition of Al_2O_3 in their core and the composition of MgO or MgO・Al_2O_3 on their exterior shell. These kinds of inclusions are difficult to aggregate and the formation of Al_2O_3 cluster is therefore prevented.3. The water model experiment was conducted to study collision and attachment of inclusions to rising bubbles and absorption of inclusions by slag with the aid of high speed camera. Effects of various operating parameters on collision and attachment of inclusions to the rising bubbles were clarified.4. Resulfurization in desulfurization process with in situ produced Mg vapor was studied. The mechanism of resulfurization was elucidated. And addition of CaO and the activated charcoal powders onto the melt surface were proposed to prevent resulfurization.5. Microscopic observation of aluminothermic reduction of MgO showed that the reduction proceeded along with penetration of molten aluminum into MgO phase after breakup of the Al_2O_3 film on Al particles. Less