Green and efficient red mud carbon dioxide carbonized dealkalization system and process

Abstract

The invention relates to a green and efficient red mud carbon dioxide carbonized dealkalization system and process. The dealkalization system comprises a red mud slurry stirring tank, a carbonization reactor, a de-ironing separator, a dewatering screen, an ion separator and a water storage tank which are connected in sequence, the dealkalization process comprises the following steps: carrying out pre-carbonization reaction on the prepared red mud slurry and CO2 introduced into the bottom of a red mud slurry stirring tank; introducing CO2 into the carbonization reactor to carry out carbonization and dealkalization, and carrying out ultrasonic treatment on the slurry at the same time; carrying out iron removal and dehydration / screening on the obtained slurry to obtain a filtrate and a dealkalized red mud product with low water content; and precipitating the filtrate, separating by an ion separator to obtain a concentrated solution containing high-concentration carbonate and a low-concentration circulating solution, drying the concentrated solution to obtain carbonate, and recycling the low-concentration circulating solution as circulating water. According to the method, continuous efficient red mud carbonization dealkalization in the whole process is achieved, no harmful substances are generated in the reaction process, the dealkalized red mud is subjected to graded separation, carbonate products are efficiently recycled, and water resources are recycled.

Description

technical field [0001] The invention relates to the technical field of industrial waste disposal, in particular to a green and efficient red mud carbon dioxide carbonization dealkalization system and process. Background technique [0002] In the alumina industry, a large amount of industrial waste slag discharged after extracting alumina from bauxite is red because it contains a large amount of iron oxide, and is called red mud. Generally, 0.6-2.0 tons of red mud will be discharged for every 1 ton of alumina produced. The Bayer method, sintering method and combined method used in the alumina industry all require dissolution in an alkaline environment during the process of extracting alumina from bauxite, which results in a large amount of alkaline substances in the red mud. Taking red mud produced by Bayer method as an example, its pH value is as high as 11 or above. At present, there is no effective technology and scheme for large-scale utilization of red mud in the world...

AI Technical Summary

Problems solved by technology

However, these technologies have one or more problems such as low efficiency, secondary pollution, and poor production continuity.

Taking the carbonization dealkalization method as an example, using CO in industrial tail gas 2 Carbonation reaction with alkaline substances in red mud to produce carbonate usually takes a long time, and most of the existing technologies are intermittent disposal, which cannot be operated continuously

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