Methods for Alkaline Recovery of Aluminum from Bauxite Residue

详细信息    查看全文

• 作者：Frank M. Kaußen ; Bernd Friedrich
• 关键词：Bauxite residue ; Red mud ; Aluminum extraction ; Aluminum recovery ; Sodium carbonate sintering ; Bayer process
• 刊名：Journal of Sustainable Metallurgy
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：2
• 期：4
• 页码：353-364
• 全文大小：1598KB
• 刊物类别：Metallic Materials; Sustainable Development; Industrial Chemistry/Chemical Engineering;
• 刊物主题：Sustainable Development; Metallic Materials;
• 出版者：Springer International Publishing
• ISSN：2199-3831
• 卷排序：2

文摘

Different ways for alkaline recovery of aluminum from bauxite residue are considered from the literature and examined in experiments. The advantages and disadvantages of a high-temperature digestion via Bayer process and soda-lime sintering process are elaborated and compared. As a hybrid process, bauxite residue undergoes a reductive smelting process with lime addition in an electric arc furnace in order to generate alumina-enriched slag. This slag is subsequently treated with high-pressure caustic leaching at moderated (200–300 g/l) and high (572–762 g/l) sodium hydroxide concentrations. The aluminum extractions are related to phase transitions in mineralogy caused by the process parameter and are analyzed and proofed by x-ray diffraction. The results show moderate aluminum recoveries of 70 % in case of the use of Bayer process, extremely high aluminum extractions of 95 % in case of slag leaching at high NaOH concentrations, and even high recoveries of almost 90 % achieved by an optimized sinter process with subsequent leaching at 50 °C with water. Special focus throughout all experiments is set on the dissolution of silicon as major impurity in the leachate.