Process for treating free alkali in red mud by microorganisms

Abstract

The invention relates to a process for treating free alkali in red mud by microorganisms. The process comprises the steps of: injecting red mud in a stirring tank in percentage by weight after size mixing; adding an acid solution containing domesticated lactic acid bacteria or thiobacillus ferroxidans, controlling the temperature, pressure and a pH value, filtering ore pulp after being treated by microorganisms to obtain a microorganism-containing solution and red mud after being treated by the microorganisms, and sending filtrate to a microorganism culture tank for continuing culturing the microorganisms, wherein the free alkali in the red mud is less than 0.95 percent, and reaches the requirement of land rehabilitation. The process has the beneficial effects that the acid used by the process is microorganism organic macromolecule weak acid, thus compared with a treatment method using inorganic acid or alkali in the prior art, the process has the advantages of reducing cost, being high in rate of removing the free alkali, short in period, simple in process, low in cost, few in impurities in leachate, low in equipment corrosion rate, convenient for storage and transportation, and beneficial to culture and recycling of microorganisms in a subsequent solution; the treated red mud filter cake contains less than 0.95 percent of free alkali, the environmental harm to the soil is reduced, and the land rehabilitation and utilization can be performed.

Description

Technical field: [0001] The invention relates to environmental treatment of non-ferrous metal metallurgical waste, in particular to a method for treating red mud free alkali with microorganisms to achieve reclamation. Background technique: [0002] Red mud is the residue produced when bauxite is leached by strong alkali during the alumina production process. For every ton of alumina produced, 1.0 to 1.3 tons of red mud are produced. It is estimated that the world's aluminum industry produces about 60 million tons of red mud every year, and my country produces 3.8 to 4 million tons of red mud every year based on the annual processing of 6 million tons of bauxite. At present, most alumina plants around the world accumulate or pour red mud into the deep sea. The storage of red mud not only occupies a large amount of land and arable land, but also consumes more yard construction and maintenance costs, and the alkali in the red mud seeps into the ground, making the alkali unable...

AI Technical Summary

Problems solved by technology

This method of dealkalization with inorganic alkali is complex in process, and the product is calcium aluminate, which is not conducive to soil reclamation.

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