熟料烧结过程热力学分析

【作者】 吕卫君；

【导师】 李小斌；

【作者基本信息】 中南大学 ， 有色金属冶金， 2005， 硕士

【摘要】 世界上大部分氧化铝由拜耳法生产,国内外对此过程进行了大量研究。由于我国的铝土矿资源中低品位居多,烧结法占有特殊地位,因此深入研究熟料烧结过程对我国氧化铝生产有重大的现实意义。 论文对熟料烧结过程涉及的已知反应进行归纳整理,同时对氧化铝生产中未见报道的反应进行探讨。考虑体系中生成其它物质的可能性,并针对烧结过程中存在的反应及其特点,本论文将熟料烧结过程反应划分为如下体系进行研究,即六个二元系（Na₂O-Al₂O₃系、CaO-Al₂O₃系、CaO-SiO₂系、Na₂O-Fe₂O₃系、Fe₂O₃-CaO系和Na₂O-SiO₂系）,两个三元系（Na₂O-CaO-Al₂O₃系和Al₂O₃-CaO-SiO₂系）,三个多元系（Na₂O-Al₂O₃-CaO-SiO₂系,Na₂O·Al₂O₃-Na₂O·Fe₂O₃-2CaO·SiO₂系,Na₂O·Al₂O₃-Na₂O·Fe₂O₃-mCaO·Fe₂O₃-2CaO·SiO₂系）。在此基础上,研究了烧结过程中众多反应的热力学问题,试图分析同一体系中各种反应进行的优先性及稳定顺序,探讨多元平衡固相中的组成和结构,从而为确定合理的工艺参数以及选择性强化熟料烧结过程反应从热力学层面提供理论依据。 论文对CaO—SiO₂系及高岭土烧结反应过程进行了实验验证。研究了氧化钙和高岭土以[CaO]/[SiO₂]摩尔比1和2分别和二氧化硅混合烧结时烧结料的组成和烧结反应率,并将烧结料用NaOH、Na₂CO₃、NaAl（OH）₄溶液进行溶出,考查其反应特性。更多还原

【Abstract】 The dominant process of alumina production is Bayer process in the world, and the researches are mostly concerning this process. But for the uniqueness of the ore, mixed process and sintering process act special roles in our country. So it has great meanings to work over the sintering process.This dissertation classified the known reactions of sintering process and discussed the reactions which have never been reported, thought over the possibilities of other compounds’ creation. Then the process was compartmentalized to different systems according to the existent reactions and their own peculiarities, which were listed as six binary systems （Na₂O-Al₂O₃ system, CaO-Al₂O₃ system, CaO-SiO₂ system, Na₂O-Fe₂O₃ system, Fe₂O₃-CaO system and Na₂O-SiO₂ system）, two trinal systems （Na₂O-CaO-Al₂O₃ system and Al₂O₃-CaO-SiO₂ system）, three multisystems （Na₂O-Al₂O₃-CaO-SiO₂ system, Na₂O ·Al₂O₃-Na₂O · Fe₂O₃-2CaO · SiO₂ system, Na₂O · Al₂O₃-Na₂O · Fe₂O₃-mCaO ·Fe₂O₃-2CaO ·SiO₂ system）. Based on the mentions above, a large quantity of thermodynamic problems regard to the reactions were studied. The course and stability were analysed to discuss the component and construction of multi-equilibrium solid phase, which can offer reasonable technologic parameters to restrain unwanted reactions and intensify wanted reactions.The reactions of CaO-SiO₂ system and kaolin were investigated. CaO and kaolin were mixed with SiO₂ and then sintered according to [CaO]/[SiO₂] mole ratio 1 or 2,respectively.The components and reaction rates of the sinters were detected and then leached in NaOH Na₂CO₃ NaAlO₂ solutions to know the reaction properties.更多还原