真空铝热还原LiAlO2制取金属锂的研究

真空金属热还原法是一种具有工业应用前景的炼锂方法。本文对常压下以工业碳酸锂、氧化铝和氧化钙为原料合成LiAlO2以及真空条件下铝热还原LiAlO2提取金属Li进行了实验研究。研究了不同煅烧条件对LiAlO2合成的影响以及不同还原条件对铝热还原制取金属锂过程的影响。结果表明:在制团压力50MPa、煅烧温度1073 K和煅烧时间120 min的条件下,碳酸锂的分解率为98.21%,煅烧产物为LiAlO2和CaO。在还原温度1423 K,时间180min,铝粉过量20%,物料粒度-75μm和制团压力为45MPa的条件下金属锂的还原率为95.50%,铝粉利用率为79.17%。还原渣主要成分为CaO.Al2O3和12CaO.7Al2O3,可用于溶出氧化铝。

Production of Lithium from LiAlO3 by Vacuum Aluminothermic Reduction

A novel technique was developed to extract lithium from LiAlO3 by vacuum aluminothermic reduction.In the newly-developed technique,the LiAlO3 were prepared in ambient environment with reactants of industrial lithium carbonate,analytical alumina and calcium dioxide;then metal lithium was vacuum extracted from LiAlO3 with Al powder as the reducing agent.The impacts of the conditions of LiAlO3 preparation and Li reduction,such as the sintering temperature and time,size and compactness of LiAlO3 grains,Al content,reduction temperature and time,and pressure,on Li extraction were experimentally evaluated.The results show that the Li extraction strongly depends on the decomposition rate of LiAlO3 and the reduction conditions.Sintered at 1073 K for 120 min,the decomposition rate of LiAlO3 in grains made at a briguetting pressure of 50 MPa,was found to be 98.21%;and the end products mainly consist of LiAlO2 and CaO.The Li reduction rate and Al powder utilization rate were 95.50% and 79.179%,respectively,under the following conditions:at 1423 K for 180 min.with 20% excess Al powder,averaged size,-75 μm,of the LiAlO3 grains made at 45 MPa.The reduction residues mainly contained CaO·Al2O3 and 12CaO·Al2O3.