大粒径石灰石高温分解动力学  

High-temperature decomposition kinetics of large particle-size limestone

作　　者：王理猷[1] 薛正良[1] 陈凯峰 胡彬[1] WANG Liyou;XUE Zhengliang;CHEN Kaifeng;HU Bin(Key Laboratory for Ferrous Metallurgy and Resources Utilization,Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,P.R.China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用教育部重点实验室,武汉430081

出　　处：《重庆大学学报（自然科学版）》2020年第8期32-46,共15页Journal of Chongqing University

基　　金：国家自然科学基金资助项目(51374160)。

摘　　要：构建符合炼钢溅渣护炉阶段和开吹阶段在转炉中直接投入石灰石代替石灰的模型,对不同粒径、不同传热条件下的大粒径石灰石进行高温分解实验。通过实验求得石灰石分解转化率α,选取适合的反应控速环节,对不同控速环节进行分析,研究溅渣护炉阶段和开吹阶段大粒径石灰石等温加热动力学机理。结果表明:石灰石转化率随粒径增加减小,随温度升高增大;溅渣护炉阶段界面化学反应控速,分解模式为随机成核与随后生长模式,符合Avrami-Erofeev方程,最概然函数积分形式为:G(α)=[-ln(1-α)]n,n=3/4;开吹阶段产物层传热与CO2扩散控速,温度一定时,时间t和(1-α)ln(1-α)+α之间存在线性关系。The models of substituting limestone for lime in a converter in the slag-splashing furnaceprotection stage and open blowing stage of steel making were established,and the high-temperature decomposition experiments of large particle-size limestone were carried out for different particle size under different heat transfer conditions.The decomposition conversion rate of limestoneαwas obtained by experiments,and through the analysis of suitable rate control steps,isothermal kinetic mechanism of large size limestone heating in the two stages were researched.The results show that the conversion of limestone decreases with the increase of particle size and increases with the rise of temperature.Interfacial chemical reaction controls the rate in slag-splashing furnace-protection stage,the decomposition model is random nucleation and subsequent growth pattern,and its mechanism is in line with the Avrami-Erofeev equation.The most probable integral fuction of limestone decomposition is G(α)=[-ln(1-α)]n,n=3/4.Product layer heat transfer and CO2diffusion control the rate in the open blowing stage.When the temperature is constant,there is a linear relationship between time tand(1-α)ln(1-α)+α.

关 键 词：石灰石 高温分解 热重分析 动力学 

分 类 号：TQ172[化学工程—水泥工业]