Study on the behavior of sodium, aluminum and silicon in the melting reduction of high-iron red mud

With the development of the alumina industry in China, a large amount of high-iron red mud has been stockpiled. The storage of red mud not only has increased the production cost of alumina enterprises but also has caused environmental pollution. At the same time, the metal resources in the high-iron red mud have not been effectively recovered. In this paper, the red mud with high iron content was treated by the melting reduction method. The changes in Na, Al and Si behavior in the process of red mud melting reduction were studied through the composition analysis, phase analysis and microscopic morphology analysis of the reduction slag, which provided a theoretical basis for producing cement using red mud melting reduction slag. The results showed that the Na element in the red mud is transformed from NaAlSiO₄ to NaCaAlSi₂O₇ and remains in the tailings. The Al element was mostly transformed into NaCaAlSi₂O₇, Ca₂Al(AlSi)O₇, etc., in the tailings by 3CaO·Al₂O₃, while the Si element was transformed from Ca₂SiO₄ to NaCaAlSi₂O₇, Ca₂Al(AlSi)O₇, Ca₂Al₂SiO₇, etc.