Journal of Sustainable Metallurgy ( IF 2.5 ) Pub Date : 2021-08-20 , DOI: 10.1007/s40831-021-00426-3 Hongyang Wang 1, 2 , Xiaoxue Zhang 1, 2 , Xu Peng 1 , Liqun Luo 1, 2 , Leiting Shen 3
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Aluminum-anodizing sludge (AAS), generated during the treatment of acidic waste-water in aluminum-anodizing process, is a kind of solid waste usually stockpiled due to low utilization. The recovery of aluminum and calcium from AAS through physicochemical process was systematically investigated in this paper. Phase analysis of AAS indicates that the Ca-bearing phases were CaCO3 and CaSO4·2H2O, and the Al-bearing phases were amorphous Al2O3 and Al(OH)3. The experimental results show that the readily soluble 3CaO·3Al2O3·CaSO4 was formed by sintering the AAS, while the presence of silica caused the generation of insoluble 2CaO·Al2O3·SiO2. Under the optimal conditions, more than 93% of Al2O3 in sintering product could be recovered by leaching in the mixed Na2CO3–NaOH solution. CaCO3 and 2CaO·Al2O3·SiO2 in leaching residue were efficiently separated by gravity separation, and approximately 89% of CaO in the leaching residue was enriched in the concentrate. The obtained sodium aluminate solution could be used for alumina production, and the concentrate with main phase of CaCO3 could be recycled to treat acidic waste-water generated from aluminum-anodizing process.
Graphical Abstract
中文翻译：
用物理化学法综合回收铝阳极氧化污泥中的铝和钙
铝阳极氧化污泥（AAS）是在铝阳极氧化过程中处理酸性废水过程中产生的一种固体废物，通常由于利用率低而堆积。本文系统地研究了通过物理化学过程从原子吸收光谱法中回收铝和钙。AAS的物相分析表明，含Ca相为CaCO 3和CaSO 4 ·2H 2 O，含Al相为非晶Al 2 O 3和Al(OH) 3。实验结果表明，易溶3CaO·3Al 2 O 3 ·CaSO 4由 AAS 烧结形成，而二氧化硅的存在导致不溶性 2CaO·Al 2 O 3 ·SiO 2 的生成。在最佳条件下，在混合Na 2 CO 3 -NaOH溶液中浸出可以回收烧结产物中93%以上的Al 2 O 3。浸出渣中的CaCO 3和2CaO·Al 2 O 3 ·SiO 2通过重力分离有效分离，浸出渣中约89%的CaO富集在精矿中。所得铝酸钠溶液可用于氧化铝生产，主相为CaCO的精矿3可循环用于处理铝阳极氧化过程中产生的酸性废水。
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