Abstract: Preparation of aluminum hydroxide from industrial residue of aluminum alloy surface treatment process was studied. The leaching process of Al from the industrial residue by NaOH solution and precipitation of Al(OH)3 from Al leaching solution by H2SO4 were explored. The effects of the concentration and dosage of alkali or acid, reaction temperature and time were examined. Process optimization was obtained by orthogonal experiments. The chemical composition, morphology and quality of Al(OH)3 product were examined as well. The results showed that the Al content in the dry residue was 28.7%, and Al existed as the form of Al(OH)3 crystal in the industrial residue. The optimum conditions of leaching process were the molar ratio of NaOH addition to Al(OH)3 in the industrial residue 2.88:1, reaction temperature 75℃, and reaction time 55 min. At these conditions, the maximum yield of aluminum in leaching process reached up to 97.5%. At the optimal conditions of precipitation process of Al(OH)3, such as the molar ratio of H2SO4 addition to AlO2- in leaching solution (0.95~1.10):1 and pH value 5.5, the precipitation yield of Al(OH)3 reached up to 89.2%, and the total recovery rate of aluminum was obtained by 87.1%. The Al(OH)3 product was amorphous with the diameter of particles of about 17 mm. The purity of Al(OH)3 in the product was up to 95.5%.

Key words: aluminum alloy surface treatment, industrial residue, aluminum hydroxide, preparation, leaching, precipitation

摘要： 研究了以铝合金表面处理工业废渣为原料制备Al(OH)3的工艺，探讨了NaOH浸提Al和H2SO4法沉淀制备Al(OH)3的过程，考察了碱酸浓度及用量、温度、时间等对制备过程的影响，采用正交实验确定了最佳工艺条件，分析了Al(OH)3产品的化学组成、形貌和质量. 结果表明，干燥废渣中Al含量为28.7%，以Al(OH)3晶体存在. 在加入的NaOH与废渣中Al(OH)3摩尔比为2.88:1、反应温度75℃、时间55 min的最佳浸提条件下，Al浸出率达97.5%. 在加入的H2SO4与浸提液中AlO2-摩尔比为(0.95~1.10):1及pH=5.5的最佳沉淀条件下，Al(OH)3的沉淀收率为89.2%，Al总回收率为87.1%. Al(OH)3产品为无定型白色粉末，粒径约为17 mm，纯度达95.5%.

关键词: 铝合金表面处理, 工业废渣, 氢氧化铝, 制备, 浸提, 沉淀