Method for processing Bayer process red mud through calcification-carbonization one-step method

Abstract

The invention relates to a method for processing Bayer process red mud through a calcification-carbonization one-step method and belongs to the field of environmental protection. The method comprises the steps of first mixing Bayer process red mud, lime and transition liquid, causing the transition liquid to be clear water or a solution with the mass concentration of Na2O not larger than 40 g / L, and calcifying the mixed pulp; causing the pulp after the transition not to undergo solid-liquid separation, directly adding pressurized gas containing a CO2 component into a reaction system, and performing a carbonization transition reaction; causing the pulp having undergone the carbonization transition to undergo solid-liquid separation, obtaining tailings and a liquid phase, causing the tailings to undergo aluminum hydroxide extraction through soluble aluminum mother liquid and then serve as a cement industry raw material or soil, and causing the liquid phase to return a Bayer process system. According to the method, red mud no-alkalinization and aluminum oxide recycling can be achieved through calcification-carbonization one-step transition processing, and the method is an energy-saving environment-friendly Bayer process red mud short process processing method.

Description

Technical field: [0001] The invention relates to the technical field of environmental protection, in particular to a one-step calcification-carbonization method for processing Bayer process red mud. Background technique: [0002] Since 2007, China's aluminum industry has entered a stage of rapid development. In 2014, my country's alumina production capacity reached about 50 million tons, twice that of 2007 (about 7 times that of 2004), and the discharge of red mud also reached 50 million tons. Tons, production capacity and emissions accounted for about 50% of the world. High-alkali red mud is the solid waste with the largest discharge in the aluminum industry. Every ton of alumina produced will produce 1-1.4 tons of red mud. At present, the total stockpiles in my country have reached about 400 million tons. The pH value of Bayer red mud is 11.0-12.0, which is highly corrosive to organisms and metal materials. The alkalinity of red mud attached liquid is as high as 26348mg / L...

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Problems solved by technology

[0004] The above-mentioned patented technologies are all aimed at energy saving and consumption reduction in the alumina production process and the harmless utilization of red mud, but none of them have achieved the goal of completely solving the alkali content in red mud and greatly reducing the energy consumption in the production process.

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