(中南大学 冶金科学与工程学院,长沙 410083)
摘 要: 铝酸钠溶液分解是碱法生产氧化铝过程的关键环节。总结铝酸钠溶液分解过程的理论及技术研究进展,论述铝酸钠溶液分解过程的热力学和宏观动力学、铝酸钠溶液的结构及其演变规律、氢氧化铝颗粒行为、分解体系固−液界面作用调控以及铝酸钠溶液分解技术等。认为铝酸钠溶液分解过程中有利于氢氧化铝析出的含铝离子是 ,调控溶液中其他复杂含铝离子结构向该类结构转变则有利于氢氧化铝析出;增大分解末期体系中最小颗粒尺寸是提高分解深度的关键;协同调控分解过程中溶液物理化学性质、离子结构和固−液界面作用的原理和方法是强化铝酸钠溶液分解技术研究的基础。
关键字: 铝酸钠溶液;晶种分解;机理;技术;研究进展
gibbsite precipitation from sodium aluminate solution
(School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract:The precipitation of sodium aluminate solution is the key process for alumina refinery by alkaline method. The research progress in theory and technology of the precipitation process was summarized. Five important aspects, including the thermodynamics and macrokinetics, aluminium-bearing species present in the aluminate solution and the species evolution, the behavior of aluminum trihydroxide particles, the interaction regulation of the interface between gibbsite particles and aluminate solution and the strengthening techniques for gibbsite precipitation, were discussed. It is held that the aluminate species favoring gibbsite precipitation is and thus the ways of converting other complex aluminate species to would increase the precipitation rate, and that the key of improving the precipitation rate is to increase the smallest particle size in the late period of precipitation. It is also held that it is the research fundamental of seeded precipitation to study the principle and method for coordinately regulating physicochemical properties of aluminate solution, ion structure and the interaction of the interface between gibbsite particle and aluminate solution.
Key words: sodium aluminate solution; seeded precipitation; mechanism; technology; research progress