Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. ...Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. The content of Fe （calculated in Fe203） in red-mud was reduced from 17.6% to less than 1% after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h. The Fe（Ⅲ） oxalate solution obtained was then irradiated by UV light, resulting in the precipitation of Fe（Ⅱ） oxalate. Under UV photocatalysis, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（Ⅱ） oxalate crystallite （fl-FeC2O4·2H2O）. The filtrate from the Fe（Ⅱ） oxalate precipitate filtration could be reused in the next cycle. The mechanism ofUV photocatalysis precipitation was also discussed.展开更多
Bayer＇s process revolutionized the extraction of aluminum from the bauxite ores. However, the hydrothermal extraction of alumina is associated with the generation of a byproduct, red-mud consisting of undis- solved s...Bayer＇s process revolutionized the extraction of aluminum from the bauxite ores. However, the hydrothermal extraction of alumina is associated with the generation of a byproduct, red-mud consisting of undis- solved solids composed of iron oxides, sodium alumino silicates, titania, silica and rare earth elements. The accumulation of red-mud （or bauxite residue） in the world is 30 billion metric tons produced at a rate of 125 million tons per annum （2013）. Utilization of red-mud for constructional purposes, wastewater treatment, metallurgical products, and pigments are listed. Metallurgical processing efforts of red-mud to generate various value added products such as pig iron, direct reduced iron slag wool, magnetite, titania, iron carbides are presented in the article.展开更多
基金Project (2010AA101703) supported by the National Hi-tech Research and Development Program of China
文摘Red-mud is the residue from the Bayer process, in which the iron minerals should be removed before red-mud is used to produce refractory materials. The iron minerals in red-mud were extracted by oxalic acid solution. The content of Fe （calculated in Fe203） in red-mud was reduced from 17.6% to less than 1% after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h. The Fe（Ⅲ） oxalate solution obtained was then irradiated by UV light, resulting in the precipitation of Fe（Ⅱ） oxalate. Under UV photocatalysis, more than 90% of Fe（Ⅲ） oxalate in the extracted solution was transformed into the precipitation of Fe（Ⅱ） oxalate crystallite （fl-FeC2O4·2H2O）. The filtrate from the Fe（Ⅱ） oxalate precipitate filtration could be reused in the next cycle. The mechanism ofUV photocatalysis precipitation was also discussed.
文摘Bayer＇s process revolutionized the extraction of aluminum from the bauxite ores. However, the hydrothermal extraction of alumina is associated with the generation of a byproduct, red-mud consisting of undis- solved solids composed of iron oxides, sodium alumino silicates, titania, silica and rare earth elements. The accumulation of red-mud （or bauxite residue） in the world is 30 billion metric tons produced at a rate of 125 million tons per annum （2013）. Utilization of red-mud for constructional purposes, wastewater treatment, metallurgical products, and pigments are listed. Metallurgical processing efforts of red-mud to generate various value added products such as pig iron, direct reduced iron slag wool, magnetite, titania, iron carbides are presented in the article.
