Coal fly ash (CFA) is one of the largest forms of global industrial waste, and continuous accumulation of CFA puts great pressure and poses potential risks to the natural environment. The objective of this study was to evaluate a sustainable process to recycle valuable elements in high-alumina coal fly ash (HACFA). In this study, an efficient and applicable approach was developed to recover Al selectively from HACFA, while most Fe recovery and removal were realized simultaneously in the leaching process. First, the thermodynamic stability of HACFA and the feasibility of Al leaching in HACFA were calculated. Then, HACFA was subjected to nitric acid pressure leaching to selectively extract Al. Under the optimal conditions (temperature of 220 °C, nitric acid concentration of 300 g/L, liquid-to- solid ratio of 4 mL/g, and duration of 2 h), 84.24% of the Al was extracted, and the leaching rate of Fe was 6.67%. The concentrations of Al and Fe in the leachate were 46.34 g/L and 0.52 g/L, respectively. The separation of Al and Fe was completed in the leaching process. The leach liquor was purified to further remove impurities, and Al₂O₃ was obtained after crystallization and pyrolysis of the aluminum-rich leachate. Leach residue was mainly composed of silica and Fe₂O₃. This process provides a feasible method for the recovery and utilization of valuable components in HACFA.

粉煤灰（CFA）是全球最大的工业废物之一，CFA的持续积累给自然环境带来巨大压力和潜在风险。本研究的目的是评估回收高铝粉煤灰 (HACFA) 中有价值元素的可持续工艺。在本研究中，开发了一种有效且适用的方法来选择性地从 HACFA 中回收铝，而大部分铁的回收和去除是在浸出过程中同时实现的。首先，计算了 HACFA 的热力学稳定性和 HACFA 中铝浸出的可行性。然后，对 HACFA 进行硝酸加压浸出以选择性提取 Al。在最佳条件下（温度 220 ℃，硝酸浓度 300 g/L，液固比 4 mL/g，持续时间 2 h），84。铝的提取率为24%，铁的浸出率为6.67%。渗滤液中铝和铁的浓度分别为 46.34 g/L 和 0.52 g/L。在浸出过程中完成了Al和Fe的分离。对浸出液进行提纯以进一步去除杂质，Al富铝渗滤液经结晶和热解后得到₂ O _{3 。}浸出渣主要由二氧化硅和Fe ₂ O ₃组成。该工艺为HACFA中有价值成分的回收利用提供了一种可行的方法。