Preparation method of low-lithium alumina used for TFT-LCD glass

A preparation method of low-lithium alumina used for TFT-LCD glass comprises the following steps: (1) selecting alumina powder with the lithium content being not more than 150 ppm; (2) removing iron from the alumina powder; (3) calcining the obtained alumina powder by a high-aluminum sagger, and removing lithium from the high-aluminum sagger; (4) adding a mineralizing agent to the obtained alumina powder, uniformly mixing the alumina powder with the mineralizing agent, and filling the selected high-aluminum sagger with the obtained mixture; (5) sending the high-aluminum sagger with the alumina powder and the mineralizing agent into a tunnel kiln, and calcining the high-aluminum sagger; (6) separating alumina in high-aluminum sagger; (7) crushing the obtained alumina, and carrying out grinding and homogenizing treatment; and (8) detecting the obtained alumina, choosing alumina with the lithium content being not more than 10 ppm, and packaging and warehousing the chosen alumina. The method has the advantages of