钠盐对耐火材料的腐蚀机制研究

发布时间：2018-03-05 03:35

本文选题：耐火材料　切入点：Na_2CO_3　出处：《华北电力大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：随着经济和工业的发展,耐火材料被广泛利用于各领域的高温工业生产中。目前,在废液焚烧和垃圾处理等含有碱金属类物料的锅炉运行过程中,耐火材料腐蚀严重,使用寿命缩短,这严重影响锅炉的安全运行,造成了非常大的经济损失。碱炉中耐火材料的钠盐腐蚀成为影响整个锅炉效益和安全的重要问题,耐火材料的钠盐腐蚀问题亟待解决,因此研究钠盐对耐火材料的腐蚀问题,对碱炉应用的工业领域具有一定意义。本文以碱炉中耐火材料的钠盐腐蚀问题为背景,以碱炉中常用耐火材料组分为原料,研究其腐蚀热力学特性和动力学机制。首先利用FactSage数据库软件计算各反应吉布斯自由能,从热力学理论上说明耐火材料各组分被碳酸钠腐蚀反应的方向性及难易程度,并采用XRD分析方法,用热力学高温实验验证理论计算,结果表明,镁铝质耐火材料的热稳定性和抗碳酸钠腐蚀性能均最好,而含铬耐火材料组分易与碳酸钠反应。本文还进一步综合分析得出耐火材料尖晶石组分与Na2CO3反应的顺序为：铁铬尖晶石、镁铬尖晶石、铁铝尖晶石、镁铁尖晶石、镁铝尖晶石,氧化物组分与Na2CO3反应的顺序依次为氧化铬、氧化铁、氧化铝。文中还采用热重分析手段深入地探讨了腐蚀反应的动力学机理,得出动力学特征参数和动力学方程。结果表明：各耐火材料料组分与碳酸钠的反应均符合Avrami-Erofeev模型,积分形式为[-ln(1-α)]4,其反应机理为随机成核,随后生长。本论文为进一步说明碳酸钠对耐火材料的腐蚀提供了理论依据,也对抗钠盐腐蚀的耐火材料发展具有一定意义。
[Abstract]:With the development of economy and industry, refractories are widely used in various fields of high-temperature industrial production. At present, in the operation of boiler containing alkali metal materials, such as waste liquid incineration and waste disposal, the corrosion of refractories is serious. The shortened service life has seriously affected the safe operation of the boiler and caused a very large economic loss. The sodium salt corrosion of the refractory in the alkali furnace has become an important problem affecting the efficiency and safety of the boiler as a whole. The problem of sodium salt corrosion of refractories should be solved urgently. Therefore, the study of sodium salt corrosion on refractories is of great significance to the industrial field of alkali furnace application. The background of this paper is the sodium salt corrosion of refractories in alkali furnaces. The corrosion thermodynamic characteristics and kinetic mechanism of common refractory components in alkali furnace were studied. Firstly, the Gibbs free energy of each reaction was calculated by using FactSage database software. The directivity and the degree of difficulty of corrosion reaction of refractories by sodium carbonate are explained from the thermodynamic theory. The theoretical calculation is verified by using XRD analysis method and thermodynamics high temperature experiment. The results show that, Mg-Al refractories have the best thermal stability and corrosion resistance to sodium carbonate. The composition of the refractory containing chromium is easy to react with sodium carbonate. The order of reaction between spinel component of refractory material and Na2CO3 is as follows: Fe-Cr spinel, magnesium-chromium spinel, magnesium-aluminum spinel, magnesia-ferric spinel, magnesia-aluminum spinel. The order of the reaction of oxide components with Na2CO3 is chromium oxide, iron oxide, alumina. The kinetic mechanism of corrosion reaction is also discussed by thermogravimetric analysis. The kinetic characteristic parameters and kinetic equations are obtained. The results show that the reaction of the components of refractories with sodium carbonate accords with the Avrami-Erofeev model, and the integral form is [-lnn 1- 伪] 4, and the reaction mechanism is random nucleation. This paper provides a theoretical basis for further explaining the corrosion of refractories by sodium carbonate, and has a certain significance for the development of refractories that resist the corrosion of sodium salt.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ175.1

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