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Deep dealkalizing method of red mud in alumina factory

A deep dealkalization and aluminum plant technology, applied in chemical instruments and methods, sludge treatment, water/sludge/sewage treatment, etc., can solve the problems of low concentration of waste liquid, high dealkalization efficiency, high cost of alkali recovery, etc. Achieve the effects of low process energy consumption, high dealkalization efficiency, and low process energy consumption

Inactive Publication Date: 2013-08-21
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although there are many patents related to the dealkalization of solid waste, these patents or processes are complicated, such as the patents disclosed in application numbers 200810115235.X, 200710304312.1, 200810114803.4, etc.; Such as the patents disclosed in application numbers 200810114803.4, 200410049747.2, 200410049747.2, etc.; or the introduction of acid medium in the dealkalization process, causing sodium ions to fail to return to the alkaline system, such as the patents disclosed in application numbers 96100220.4 and 200810231008.3. High efficiency, no or a small amount of low-concentration lye technology to solve the problem of deep dealkalization of red mud

Method used

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  • Deep dealkalizing method of red mud in alumina factory
  • Deep dealkalizing method of red mud in alumina factory
  • Deep dealkalizing method of red mud in alumina factory

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Taking the red mud of an alumina plant in Henan as an example, the mass percentage (%) of the chemical composition of the red mud in the plant is as follows:

[0020]

[0021] Mix the red mud with the evaporated mother liquor with an alkali concentration of 200g / L, add quicklime so that the total calcium-silicon ratio of the slurry is 3, raise the temperature to 300°C, and react for 1.5 hours, and the liquid-solid ratio is 6. The slurry was naturally cooled to 110°C, then separated by filtration and washed. After the filter residue was dried and analyzed, the mass percent content of sodium oxide was 0.31%.

Embodiment 2

[0023] Mix the red mud of the alumina plant in Example 1 with the evaporated seed liquor with an alkali concentration of 300g / L, add quicklime according to the slurry Ca / Si ratio of 3, raise the temperature to 200°C, and react for 1.5 hours, with a liquid-solid ratio of 10. After the reaction, the slurry was naturally cooled to 110° C., filtered, washed, and the filter cake was dried. After analysis, the percentage content of sodium oxide in the final slag was 1.51%.

Embodiment 3

[0025] Mix the red mud of the alumina plant in Example 1 with the mother liquor with an alkali concentration of 260g / L, add quicklime according to the slurry Ca / Si ratio of 2, raise the temperature to 300°C, and react for 0.5 hours, with a liquid-solid ratio of 3. After the reaction, the slurry is pumped into the flash tank, flashed to 115°C, and then pumped into the filter for filtration. The obtained slag phase was fully washed and filtered. After the filter residue was dried, its sodium oxide percentage was analyzed to be 0.89%.

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Abstract

The invention provides a deep dealkalizing method of red mud, which is an alumina factory solid waste. According to the invention, under a temperature of approximately 250 DEG C, seed liquor which is evaporated to a certain concentration is added to calcium oxide, and the mixture is used for deep processing red mud; through the changing of the phase of the red mud, highly efficient recovery and utilization of sodium oxide in red mud is realized. After a reaction is finished, an obtained mixture is filtered and separated, and the filtrate is delivered back to a bauxite dissolution section. Themethod is convenient to be linked with an existing Bayer process. After processing, a mass percentage of sodium oxide in a finished slag is reduced to approximately 1%, and no low-concentration lye is produced during the process, such that an environmental risk of red mud is eliminated, and red mud can be used in construction raw materials in large scales with low energy consumption. Therefore, the waste is turned into a resource, and the waste turns environment-friendly.

Description

technical field [0001] The invention relates to a treatment technology for solid waste, in particular to a treatment method for deep dealkalization of solid waste in an alumina plant. Background technique [0002] At present, my country's solid waste from alumina plants, that is, red mud, is mainly treated by stockpiling. This method not only occupies land, but also costs a lot of treatment. Once leakage occurs, it will pollute the land and the surrounding groundwater sources, bringing a series of problems. environmental and social issues. The main reason for restricting the large-scale application of this solid waste is that it contains about 10% by mass of sodium oxide. Although there are many patents related to the dealkalization of solid waste, these patents or processes are complicated, such as the patents disclosed in application numbers 200810115235.X, 200710304312.1, 200810114803.4, etc.; Such as the patents disclosed in application numbers 200810114803.4, 200410049...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00
Inventor 马淑花张然郑诗礼张盈张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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