Method for dissolving Bayer process red mud

Abstract

The invention discloses a method for dissolving red mud. The method comprises the following specific steps of: mixing Bayer process red mud with white lime in the mass ratio of 1:(0.3-0.9); stirring at the temperature of 80-140 DEG C for reacting for 1-15 hours for calcifying, transforming and dealkalizing; mixing calcified, deformed and dealkalized Bayer process red mud with clear water or a low-concentration sodium aluminate solution in an enclosed container; introducing CO2 into the container to obtain calcified slag containing calcium silicate, calcium carbonate and aluminum hydroxide serving as main components; and extracting aluminum hydroxide from the calcified slag by using a sodium hydroxide solution or an aluminum hydroxide solution. In the method disclosed by the invention, the structure and composition of red mud are changed by adopting calcification transformation and pressurizing calcification transformation methods, so that dealkalization and extraction of aluminum can be realized; and iron is extracted properly, so that the structure and the composition of red mud can meet the requirements of cement production, and the aim of dissolving red mud on a large scale at low cost is fulfilled.

Description

technical field [0001] The invention belongs to the field of comprehensive utilization of metallurgical secondary resources, and in particular relates to a method for consuming Bayer process red mud. technical background [0002] Red mud is the most important waste in the alumina industry. According to the production process, it can be divided into Bayer red mud and sintering red mud. In 2010, my country's alumina output reached 28.96 million tons, and a total of 35.374 million tons of red mud was produced, that is, every The production of 1 ton of alumina produces more than 1.2 tons of red mud, of which sintering red mud accounts for 18.1%, and Bayer red mud accounts for 81.9%. Compared with sintering red mud, the utilization of Bayer red mud is more difficult. This is because the main component of Bayer red mud is hydrated sodium aluminosilicate during the production of alumina by Bayer method, and another part contains The components of calcium, iron and titanium, so the ...

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Problems solved by technology

[0004] Aiming at the problems of high cost and low comprehensive utilization rate of valuable components in the existing red mud treatment technology, the present invention provides a method for consuming Bayer red mud, which realizes The transformation and dealkalization of red mud, and the recovery of alumina and sodium alkali, and the recovery of part of the iron in the red mud through iron extraction, its economic benefits are much higher than the existing red mud treatment methods, which are independently developed by Northeastern University NEUZ large-scale low-cost red mud consumption technology

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