Effect of BaO, Basicity and Temperature on Manganese Distribution between Slag and Hot Metal in Blast Furnace

Abstract

Daily average data obtained on the 1033 m3 blast furnace No.3 of the Egyptian Iron and Steel Company (EISCO) were used to investigate the effects of BaO, basicity and temperature on the activity coefficient and activity of MnO in the slag as well as on the manganate capacity and manganese distribution between slag and metal. The activity coefficient was estimated by using the regular ionic solution model. Both activity coefficient and activity increase with increasing basicity and BaO content of the slag. The activity, manganate capacity and manganese distribution ratio are largely dependent on temperature and change only slightly with the basicity. The relative partial molar enthalpy of solution of MnO in the slag is 107 kJ/mol. The relationship between activity and concentration of MnO in the slag is linear over the whole ranges of temperature (1400 to 1450°C) and basicity, (CaO/SiO2 = 0.61-0.95). The concentration dependence of manganese activity in hot metal is also linear and the activity coefficient of Mn in hot metal is 0.51. The distribution ratios calculated by using the concept of manganate capacity were correlated with the relevant values obtained from the slag and metal analyses. The calculated partition ratios are in agreement with the observed values. In all cases, empirical equations have been derived.