A method for strengthening red mud dealkalization with aluminum and separating and recovering aluminum and iron

Abstract

The invention discloses a method for aluminum-strengthened red mud dealkalization and separation and recovery of aluminum and iron. The method is to dissolve red mud in water and feed excess SO 2 , while introducing oxygen aeration, and refluxing part of the filtered alkaline leachate; when the pH of the red mud mixture drops below 3, wash and filter the red mud mixture, and then add NaOH to the acidic leachate to adjust the pH to strong alkaline , and age and filter the leachate again, process the filter residue, and recover Fe 2 o 3 At the same time, the filtered alkaline leaching solution is partially refluxed into the red mud mixture; the remaining filtered alkaline leaching solution is adjusted to a weakly acidic pH, and then filtered to recover aluminum. The present invention feeds SO into red mud mixed liquor 2 Carry out acidification desulfurization, filter and contain Al 3+ Part of the alkaline leaching solution is refluxed into the red mud mixture to strengthen the dealkalization of the red mud; the filter residue obtained after filtering the alkaline leaching solution is dried and sintered to obtain almost pure Fe 2 o 3 ; The remaining filtered alkaline leachate adjusts the pH to weakly acidic, and can be filtered to recover Al(OH) 3 .

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,...

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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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