Method for dealkalizing aluminum-reinforced red mud and separating and recovering aluminum and iron

Abstract

The invention discloses a method for dealkalizing aluminum-reinforced red mud and separating and recovering aluminum and iron, which comprises the following steps: dissolving red mud in water, introducing excessive SO2, introducing oxygen for aeration at the same time, and enabling a part of filtered alkaline leachate to flow back; when the pH value of a red mud mixed solution is reduced to 3 or below, conducting washing and filtering on the red mud mixed solution, then adding NaOH into an acidic leachate to adjust the pH value to strong alkalinity, conducting aging and filtering on a leachateagain, treating filter residues, recovering Fe2O3, and meanwhile, enabling the filtered alkaline leachate to flow back to the red mud mixed solution; and adjusting the pH value of the residual filtered alkaline leachate to be weakly acidic, and then conducting filtering to recover aluminum. According to the method, SO2 is introduced into the red mud mixed solution for acidification and desulfurization, a part of filtered alkaline leachate containing Al<3+> flows back to the red mud mixed solution, and thus dealkalization of the red mud is reinforced; and filter residues obtained by filteringthe alkaline leachate are subjected to the steps of drying, sintering and the like, and almost pure Fe2O3 can be obtained; and the pH value of the residual filtered alkaline leachate is adjusted to beweakly acidic, and Al(OH)3 can be recovered through filtering.

Description

technical field [0001] The invention belongs to the fields of metallurgy and environmental protection, further belongs to the technical field of industrial flue gas pollutant control, and specifically relates to a method for aluminum-enhanced dealkalization of red mud and separation and recovery of aluminum and iron. Background technique [0002] Red mud is the polluting waste slag removed from the alumina industry, and about 1t~1.8t of red mud is produced for every 1t of alumina produced. As the fourth largest producer of alumina, my country discharges more than 5.5 million tons of red mud every year. At present, most of the red mud reservoirs (dams) are wet stored or dehydrated and dried, which not only encroach on farmland, but also have hidden dangers of dam failure. Red mud contains 3%~10% Na 2 O, with strong alkalinity, unreasonable stacking may easily cause soil and groundwater pollution. At the same time, the dust formed by the exposed red mud flies with the wind,...

AI Technical Summary

Problems solved by technology

These methods have a good effect on the dealkalization of red mud, but the technology is complicated, the energy consumption is high, it is difficult to realize industrialization or the cost of industrial production is high

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