CO还原CaO－SiO_2－Al_2O_3－Fe_tO渣系研究

REDUCTION OF CaO-SiO_2-Al_2O_3-Fe_ tO QUARTERNARY SLAG SYSTEM BY CO

研究了在１７２３Ｋ下ＣＯ还原ＣａＯ－ＳｉＯ_２－Ａ１_２Ｏ_３－Ｆｅ_ｔＯ渣系。根据ＣＯ_２红外分析仪测定的出口气体中ＣＯ_２浓度变化，计算了炉渣的表现还原速度常数Ｋ_ａ和还原速度常数Ｋ。结果表明，加入Ａｌ_２Ｏ_３，提高了ＣａＯ－ＳｉＯ_２－Ｆｅ_ｔＯ的Ｋ_ａ和Ｋ值；炉渣碱度不变时，随着Ｆｅ_ｔＯ含量的增加，Ｋ_ａ呈增加趋势，但Ｋ则呈抛物线趋势变化；当ＦｅＯ的光学碱度∧_ＦｅＯ为１．０或０．８７时，Ｋ_ａ随该四元渣系光学碱度的增加而线性增加，而Ｋ则呈递减趋势。用炉渣规则溶液模型计算了ＣａＯ－ＳｉＯ_２－Ａｌ_２Ｏ_３－Ｆｅ_ｔＯ四元渣系的Ｆｅ_ｔＯ活度ａ_Ｆｅ_ｔＯ。

The reduction of CaO-SiO_2-Al_2O_3-Fe_tO quarternary slag system by CO has been investigated. Apparent reduction rate constant K_ a was determined by mesuring CO_2 evolution from reaction tube with an infrared gas analyser. Adding Al_2O_3 to CaO-SiO_2-Fe_tO ternary slag increases both K_a and reduction rate constant K of CaO-SiO_2-Fe_tO ternary slag. K_a increases and K changes parabolicly with increasing Fe_tO content for CaO-SiO_2-Al_2O_3-Fe_tO slag system at constant slag basicity (B=CaO/SiO_2),and K approaches to the minimum when Fe_tO content is about 60%. K_a increases linearly and K takes a decrease tendency with the increase of optical basicity for A_(FeO) chosen as 1.0 or 0.87. The equation of calculating a_(Fe_tO) for CaO-SiO_2-Al_2O_3-Fe_tO slag system has been derived based on regular solution model and calculated a_(Fe_tO) values are in fairly agreement with bibliography reported data except for extremely Fe_tO rich region.