Removal of Boron from Molten Pig Iron and Dissolution of B₂O₃ Slag into Water

Abstract

In order to remove B in pig iron as much as possible, the oxidation rates of elements in molten pig iron were measured by adding Fe₂O₃, CaO, Na₂CO₃, BaO, BaCO₃ and Li₂CO₃ onto the bath: In addition, to recover B₂O₃ from slag and to increase MnO content in slag, the dissolution rate of B₂O₃ in slag into the distilled water or HCI solutions was estimated. The results obtained are as follows;
(1) The removal ratio of B from pig iron was high at lower temperatures without a basic flux. However, a basic flux should be used to prevent B₂O₃ from reducing because the reduction rate of B₂O₃ was high at higher temperatures.
(2) The removal ratio of B was high under the same conditions of lower temperature, higher oxidation atmosphere, and higher slag basicity as those of dephosphorization.
(3) The dissolution ratio of B₂O₃ in slag into the distilled water at 100 °C decreased as the increase of content of MnO, FeO and SiO₂ in slag. B₂O₃ in slag dissolved completely into the HCI solutions at 50 °C above 0.25 N concentration.