【作者】 陈为亮；

【导师】 戴永年；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2000， 博士

【摘要】 本文介绍了金属锂及其化合物的性质、用途和消费情况，综述了金属锂和高纯锂的生产方法，对粗锂真空蒸馏精炼、碳酸锂真空加碳热分解、氧化锂真空碳热还原过程的热力学和动力学进行了计算与分析，对粗锂真空蒸馏精炼进行了试验研究，对氧化锂真空碳热还原提取金属锂进行了初步探索，提出了一个全新的提取锂的流程。 对粗锂真空蒸馏精炼的热力学和动力学进行了研究。计算了锂中各杂质的分离系数，作出了Li-K、Li-Na、Li-Mg、Li-Ca、Li-Al、Li-Si、Li-Fe、Li-Ni二元系在573～1273K的蒸馏温度下的气液相平衡成分图，直观地表示了粗锂中杂质的含量、蒸馏温度对蒸馏产品的影响。还计算了K、Na、Li、Mg、Ca、Al、Si、Fe、Ni在真空中的最大蒸发速率以及锂在不同蒸馏温度进行真空蒸馏时的临界压强和蒸发系数，分析了金属在真空中的蒸发过程，研究了蒸馏温度、压强、冷凝条件对蒸法过程的影响。 粗锂真空蒸馏精炼的热力学和动力学分析结果表明：根据分离系数的大小，粗锂中的杂质元素可分为三类：分离系数β_i＞1的K和Na，分离系数β_i＜1的Al、Fe、Ni、Si以及分离系数在1附近的Ca和Mg。用真空蒸馏的方法能够比较彻底地除去粗锂中的K、Na、Al、Si、Fe、Ni，而Ca和Mg的分离则较困难；为使粗锂中的杂质在真空蒸馏时与锂很好分离，应采用分步蒸馏的方法：即在较低温度下蒸馏低沸点杂质K和Na，第二步在较高温度下蒸馏锂，使高沸点杂质Al、Si、Fe、Ni残留下来。控制一定的蒸馏条件，可以使粗锂中的Ca和Mg得到比较彻底的分离。在锂的真空蒸馏过程中，由于存在临界压强，锂的蒸馏速度不能随系统压强的降低而无限增大，为保证蒸馏时锂有最大的蒸发速率，系统压强应稍低于临界压强。 以工业级粗锂为原料，研究了粗锂真空蒸馏精炼的工艺条件。考察了一段（低温）蒸馏温度、一段蒸馏时间、二段（高温）蒸馏温度、添加剂的种类和添加量五个因素对粗锂真空蒸馏精炼的影响，得到了粗锂真空蒸馏精炼的较优工艺条件：一段蒸馏温度为550℃、一段蒸馏时间为60min、二段蒸馏温度为700℃、B₂O₃的添加量为锂的2.0％（Wt.）。在此条件下，纯度为99.632％的粗锂通过真空蒸馏精炼，得到纯度＞99.9％的高纯锂。 在973～1053K的温度范围内，对金属锂真空蒸发的动力学进行了研究。得到了金属锂在不同蒸发温度下蒸发的最大蒸发速率ω_max和临界压强P_crit，发现金属锂的蒸发系数α随蒸发温度的升高而下降，得出了临界压强和最大蒸发速率与蒸发温度之间的关系式： P_crit=-4×10^-4T²+0.9207T-512.2（Pa） ω=2×10^-7T²+2×10^-4T+0.026(g·cm^-2·min^-1) 通过对碳酸锂真空加碳热分解和氧化锂真空碳热还原的热力学和动力学分析可知：在有碳存在的情况下，碳酸锂在真空和高温的条件下更容易分解，分解温度比纯碳酸锂的低约150K，并且随真空度的提高分解温度降低；在 昆明理工大学博上学位论文 摘要IAbstract 真空中碳能够将氧化理还原为金属理，随真空度的提高还原反应更容易进 行。 以碳酸理为原料，对真空碳热还原法制取金属银进行了初步研究，在压 强不变的情况下，分别考察了温度和时间对碳酸银真空加碳热分解和氧化理 真空碳热还原反应的影响，对分解反应和还原反应的反应机理和动力学模型。 作了分析和讨论。在系统压强为－15Pa、分解温度为 923～＊73K的条件下， 得出了碳酸袒真空加碳热分解反应的分解串删)与分解时间雹的关系式： 923K：卜＝6．OXW炉一！．扣XI沪一十0．4317！ 9刀K：R＝＝2．0X10－’尸一6．60X10”’尸十1．244＊ 1023K：只。2．OXI炉P一】．01 IW十1．701！！ 1073K：R＝3．OX10“P一5石SX10Y＋3．9！52t 表明分解反应属缩核反应模型和分解反应受界面化学反应所控制的反应机 理，求出了分解反应在碳酸理沼点以下（923～973K）和沼点以上0～1073切 进行的表观活化能 E。分别为 172．13 kJ／Inol和 137．58kJ／mol。 在系统压强为20Pa、还原温度为1373K和1423K的条件下，分别得到 了氧化理真空碳热还原反应的还原率用州与还原时间在的关系式： ！373K：R。7xlw一！．66x 10－2t2 －I－l．3845t 1423K：R＝！X！W一二．75 X！0“Y十二．3439t 表明氧化锰的碳热还原反应受扩散动力学控制，反应的表观活化能为391．14 kjhalo通过试验，首次制得了纯度为54。34％的金属理。 迢过以上研究，得出了以觑埋为原料，迟过真空加碳热分解、真空碳 热还原、真空蒸瞩制取金属锰的原则工艺流程，该工艺对降低金瞩理的生产 成本和环境保护具有重要意义。更多还原

【Abstract】 The properties, the application and the consumption of metal lithium and its compounds are discussed in the thesis. The preparation methods of crude lithium and high purity lithium are overviewed. The principles involved in the process of vacuum distillation refining of crude lithium, vacuum thermal decomposition of Li2CO3 with carbon and vacuum carbothermic reduction of L120 have been analyzed with thermodynamic and kinetic calculation. The refining process of crude lithium by vacuum distillation was experimentally studied. In particular, the preliminary study on the process of producing metal lithium from Li20 by vacuum carbothermic reduction was also carried out experimentally and a novel process for preparing metal lithium has been proposed. The thermodynamics and kinetics on the refining process of crude lithium by vacuum distillation are studied. The separation coefficients of the impurities in crude lithium are calculated. The liquid-vapor equilibrium composition diagram of Li-K, Li-Na, Li-Mg, Li- Ca, Li-Al, Li-Si, Li-Fe and Li-Ni binary system are worked out in a range of 573K to 1273 from which the quality of distillated lithium is how to be influenced by contents of impurities and distillation temperature is shown obviously. The maximum evaporation rates of K, Na, Li, Mg, Ca, Al, Si, Fe and Ni, the critical pressure and the accommodation coefficient of lithium during the process of distillation are also calculated respectively. The distillation process of metal in vacuum is discussed. The influences on distillation by distillation temperature, chamber pressure and condensation parameter are studied. The results from thermodynamic and kinetic analyses on lithium refining process by vacuum distillation indicate that the impurities in lithium can be classified as three kinds according to the separation coefficient: P >1 as K and Na. P <1 as Al, Si, Fe and Ni, P ~ 1 as Ca and Mg. The former two kinds of impurities can be removed easily from lithium by vacuum distillation while the removal of the impurities of Ca and Mg shows more difficult. In order to separate the impwities of crude lithium more completely in vacuum, fractional distillation should be adopted in the process. That is the impurities such as low boiling point elements of K and Na are distillated at lower temperature, then Li is distillated at higher temperature while the high boiling elements of Al, Si, Fe and Ni are remained in residue. By controlling the parameters, Ca and Mg can also be separated with Li more completely. The distillation rate of lithium can’t increase infinitely as the chamber pressure decreases because there is a known critical pressure during the process lithium’s vacuum distillation. The maximum chamber pressure should be controlled just a little less than the critical pressure to ensure the higher distillation rate of lithium during the evaporation process. With the feedstock of industry-grade lithium, the refining process of lithium by vacuum distillation was approached in more details. The principal parameters involved inthis process are the first phase (lower temperature) distillation temperature and distillation time, the second phase (higher temperature) distillation temperature, the varieties and quantities of the additives were examined. The optimized technical parameters of vacuum distillation refining have been obtained: the first step distillation temperature ~?50C, the first phase distillation period is 60mins, the second phase distillation temperature 700(2, the additive is B203 and its quantity is 2.0%(wt.). On this condition, the metal lithium with a h更多还原