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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。
Vacuum metal thermal reduction method is a kind of lithium refining method with industrial application prospect. In this paper, LiAlO2 was synthesized from industrial lithium carbonate, aluminum oxide and calcium oxide at atmospheric pressure and Li was extracted by LiAlO2 under vacuum condition. The effects of different calcination conditions on the synthesis of LiAlO2 and the effect of different reduction conditions on the process of lithium metal preparation by aluminothermic reduction were investigated. The results showed that the decomposition rate of lithium carbonate was 98.21% under the pressure of 50 MPa, the calcination temperature of 1073 K and the calcination time of 120 min. The calcined products were LiAlO2 and CaO. The reducing rate of metallic lithium was 95.50% and the utilization rate of aluminum powder was 79.17% under the condition of reduction temperature of 1423 K, time of 180 min, excess aluminum content of 20%, material size of -75 μm and system pressure of 45 MPa. The main components of reduced slag CaO.Al2O3 and 12CaO.7Al2O3, can be used to dissolve alumina.