Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

中文翻译：

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用醋酸浸出铝土矿渣中锂的行为

铝土矿渣（赤泥）是一种碱性废物，来源于从铝土矿中提取氧化铝的工业过程。一些铝土矿残留物含有相当高浓度的关键金属，例如稀土元素。赤泥中的锂也被报道为一种潜在资源。在目前的研究中，用醋酸浸出富含锂的赤泥以研究锂的浸出行为，然后用盐酸或草酸中和。通过使用稀盐酸 (0.01 mol/L) 中和赤泥，在 95°C 下使用 25% 的乙酸浸出 58.04-60.27% 的锂 60 分钟。与此同时，95%以上的钠和85%以上的钙也溶解在渗滤液中。虽然在醋酸浸出之前使用草酸 (0.5 mol/L) 中和赤泥，与使用盐酸中和的赤泥相比，锂的浸出效率较低 (42.41–46.88%)。尽管如此，在该条件下，锂的这些浸出效率接近钙的浸出效率并且远高于钠的浸出效率。在这项研究中，25% (v/v) 的乙酸，在 85 °C 下 60 分钟，被证明是使用乙酸从草酸中和的赤泥中提取锂的最佳条件。该结果对于从赤泥中回收和纯化锂是有用的和有意义的。被证明是使用乙酸从草酸中和的赤泥中提取锂的最佳条件。该结果对于从赤泥中回收和纯化锂是有用的和有意义的。被证明是使用乙酸从草酸中和的赤泥中提取锂的最佳条件。该结果对于从赤泥中回收和纯化锂是有用的和有意义的。