In this study, secondary aluminum dross as an alumina-rich resource was valorized into the gamma-aluminum oxide ($\gamma$-Al₂O₃) via a pilot-scale extraction system. The pilot-scale process was designed for a total $\gamma$-Al₂O₃ production of $\sim$5 kg/day. The extraction process included leaching, precipitation, hydroxide separation, aluminum hydroxide re-precipitation, drying and high-temperature dihydroxylation The obtained $\gamma$-Al₂O₃ was then characterized using XRD, XRF, BET, and FESEM. The XRD analysis disclosed the emergence of the gamma-crystalline phase with a crystallite size of 19.6nm. The XRF revealed a purity of more than 99 wt%. The BET surface area, pore volume, and mean pore size were $\sim$170 m²/g, 0.45cm ³/g, and 17.4nm, respectively. The FESEM and TEM indicated that the as-synthesized $\gamma$-Al₂O₃ was in the form of agglomerates, consisting of <20nm particles. The $\gamma$-Al₂O₃ was then used to adsorb aqueous fluoride with two different concentrations of 10 and 20 ppm. The adsorption results revealed that the amount of fluoride adsorbed by $\gamma$-Al₂O₃ was 16.5 mg/g when adsorbent dosage, initial fluoride concentration, pH, and equilibrium time were 1 g/l, 20 ppm, 4, and 1 h, respectively. The maximum monolayer adsorption was obtained 35.6 mg/g by Langmuir model. Investigating the influence of the adsorbent dosage indicated that the adsorbent dosage of 4 g/l resulted in 98% fluoride removal. It was found that fluoride adsorption occurred through chemisorption, and carbonate and phosphate anions had the most interference with fluoride adsorption. The regeneration experiments showed that the regenerated $\gamma$-Al₂O₃ can exhibit good fluoride adsorption performance, even after 8 times regeneration. 

在这项研究中，将次生铝渣作为一种富含氧化铝的资源转化为γ-氧化铝（$\gamma$-Al ₂ O ₃）通过中试规模的提取系统。中试规模的过程是为总体设计的 $\gamma$-Al ₂ O ₃生产 $〜$5公斤/天。萃取过程包括浸出，沉淀，氢氧化物分离，氢氧化铝再沉淀，干燥和高温二羟基化。 $\gamma$然后使用XRD，XRF，BET和FESEM对-Al ₂ O ₃进行表征。XRD分析揭示了出现了具有19.6nm微晶尺寸的γ晶相。XRF显示纯度大于99重量％。BET表面积，孔体积和平均孔径为 $〜$分别为170 m ² /g、0.45cm ³ / g和17.4nm。FESEM和TEM表明合成后的 $\gamma$-Al ₂ O ₃为附聚物形式，由＜20nm的颗粒组成。这 $\gamma$然后，使用-Al ₂ O ₃吸附具有两种不同浓度的10和20 ppm的氟化物水溶液。吸附结果表明，氟的吸附量为 $\gamma$当吸附剂量，初始氟化物浓度，pH和平衡时间分别为1 g / l，20 ppm，4和1 h时，-Al ₂ O ₃为16.5 mg / g。通过Langmuir模型获得最大单层吸附为35.6mg / g。研究吸附剂剂量的影响表明，吸附剂剂量为4 g / l导致98％的氟化物去除。发现氟化物的吸附是通过化学吸附发生的，而碳酸根和磷酸根阴离子对氟化物的吸附影响最大。再生实验表明，再生 $\gamma$-Al ₂ O ₃甚至在再生8次后仍具有良好的氟化物吸附性能。