Secondary aluminum dross (SAD) is an inevitable by-product from the secondary aluminum industry and has caused serious environmental issues. In this study, the effect of pretreatment operations on the subsequent acid leaching operation was studied by process mineralogy, a series of leaching experiments, XRD, and SEM. Leaching results showed that the leaching efficiency of Al in direct acid leaching was only 22.99%. Process mineralogy showed the complex intertexture and continuous network structure in the SAD. Pretreatment operations were extremely efficient in destroying the structure by physical and chemical interaction. Interestingly, by adding the grinding and water leaching operations, the leaching efficiency of total aluminum in the SAD reached approximately 28.70%. XRD results showed that nearly all metallic Al, AlN, and partial Al₂O₃ were leached by grinding–water leaching–acid leaching. The scanning electron micrographs showed that the residue particles mainly included some insoluble components and had a smooth surface.

中文翻译：

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预处理操作优化次生铝渣中铝浸出效率的研究

二次铝渣（SAD）是二次铝行业不可避免的副产品，已引起严重的环境问题。在这项研究中，通过工艺矿物学，一系列浸出实验，XRD和SEM研究了预处理操作对随后的酸浸操作的影响。浸出结果表明，在直接酸浸中Al的浸出效率仅为22.99％。过程矿物学显示了SAD中复杂的交织结构和连续的网络结构。预处理操作通过物理和化学相互作用非常有效地破坏了结构。有趣的是，通过增加研磨和水浸出操作，SAD中总铝的浸出效率达到了约28.70％。XRD结果表明，几乎所有金属Al，AlN和部分Al通过研磨-水浸-酸浸来浸出₂ O ₃。扫描电子显微镜照片显示，残留颗粒主要包括一些不溶成分并且具有光滑的表面。