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常压煅烧氢氧化锂、氧化铝和氧化钙混合物可得到Li_5AlO_4型富锂熟料,真空铝热还原该熟料可制备金属锂,同时获得12CaO·7Al_2O_3型还原渣,该渣通过碱液溶出、碳酸化分解可制备氢氧化铝。研究了还原温度、还原时间、铝粉过量系数对真空铝热还原制取金属锂过程的影响。结果表明:在系统压强-5 Pa,还原温度1200℃,还原时间120 min,铝粉不过量的条件下,金属锂的还原率为97.76%,还原渣主要成分为12CaO·7Al_2O_3。铝粉过量超过10%不利于金属锂还原率的提高,且还原渣的主要成分为CaO·2Al_2O_3和CaO·Al_2O_3。
Li_5AlO_4-type lithium-rich clinker can be obtained by calcining the mixture of lithium hydroxide, alumina and calcium oxide under atmospheric pressure, and the lithium metal can be prepared by thermal reduction of the clinker in aluminum hydride. At the same time, 12CaO · 7Al_2O_3- Carbonation decomposition can be prepared aluminum hydroxide. The effects of reduction temperature, reduction time and excess aluminum powder on the process of preparing metallic lithium by vacuum aluminothermic reduction were studied. The results show that the reduction rate of metal lithium is 97.76% and the main component of reduced slag is 12CaO · 7Al_2O_3 under the conditions of system pressure -5 Pa, reduction temperature 1200 ℃, reduction time 120 min and no excessive aluminum powder. Over 10% of aluminum powder is not conducive to the improvement of metal lithium reduction rate, and the main components of reduced slag CaO · 2Al_2O_3 and CaO · Al_2O_3.