火焰原子吸收光谱法测定电解铝用冰晶石中锂

含锂冰晶石取代锂盐添加到电解质中被广泛应用于电解铝工业,其质量直接影响到电解铝工业的电解效率、吨铝能耗高低和电解铝产品质量优劣。控制冰晶石中锂含量是保证产品质量和应对废旧电解质再生对氟化盐市场冲击的一个重要举措。通过在铂坩埚中加入一定量高氯酸在高温条件下加热冒烟赶氟后再加入盐酸酸化至盐类完全溶解,建立了波长670.80 nm处采用火焰原子吸收光谱法测定铝用冰晶石中锂含量的方法,避免了大量氟基体的干扰,选择一定量的铝钠基体匹配来保证测试灵敏度和准确性;通过加标回收实验得知锂的回收率为102%;锂元素校准曲线线性相关系数≥0.9994;锂的检出限为0.0065μg/mL;不同含量含锂冰晶石的锂标准偏差均小于0.01%,与电感耦合等离子体原子发射光谱(ICP-AES)法测定结果相一致。方法准确可靠、简单易操作,满足铝电解工业生产分析的需要。

Determination of lithium in cryolite for electrolytic aluminium by Flame Atomic Absorption Spectrometry

Lithium-containing cryolite is widely used in electrolytic aluminum industry instead of lithium salt. Its quality directly affects the electrolytic efficiency of electrolytic aluminum industry, the energy consumption per ton of aluminum and the quality of electrolytic aluminum products. Controlling lithium content in cryolite is an important measure to ensure product quality and to cope with the impact of waste electrolyte regeneration on fluoride market. The content of lithium in platinum crucible was determined by flame atomic absorption spectrometry (FAAS) at 670.80 nm after adding a certain amount of perchloric acid to the platinum crucible, heating, smoking and fluoride removal at high temperature, then adding hydrochloric acid to acidify and completely dissolve the salts. The method avoids the interference of fluorine matrix, and chooses a certain amount of Al-Na matrix matching to ensure the sensitivity and accuracy of the test; the recovery rate of lithium is 102.2% through standard addition recovery experiment; the linear correlation coefficient of lithium calibration curve is more than 0.9994; the detection limit of lithium is 0.0065 ug/mL; the lithium standard of lithium-containing cryolite with different content The deviations were less than 0.01%. The results obtained by this method are in agreement with those by ICP-AES. The method is accurate, reliable, simple and easy to operate, and meets the needs of production analysis in aluminum electrolysis industry.