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A kind of Bayer process red mud acid treatment method for removing alkali and recovering sodium

A Bayer red mud and acid treatment technology, applied in chemical instruments and methods, cement production, alkali metal compounds, etc., can solve the problems of high cost of red mud desodiumization, limited degree of red mud desodiumization, difficult filtration, etc., to achieve Improved filtration performance, low cost, and reduced recycling costs

Active Publication Date: 2021-02-02
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Aiming at the problems in the prior art that the filtration is difficult, the degree of sodium removal from red mud is limited, and the cost of sodium removal from red mud is high, the purpose of the present invention is to provide a method for acid treatment of red mud by Bayer method to remove alkali and recover sodium, so as to overcome the traditional acid method Disadvantages of difficult leaching and filtration

Method used

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  • A kind of Bayer process red mud acid treatment method for removing alkali and recovering sodium

Examples

Experimental program
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Effect test

Embodiment 1

[0040] The raw material is red mud tailings from an aluminum industry in Shandong, and the main content of each component is SiO 2 : 22.34%, CaO: 44.32%, Al 2 o 3 : 4.23%, K 2 O: 0.33%, Na 2 O: 7.25%, MgO: 0.52%, Fe 2 o 3 : 8.33%.

[0041] (1) Mix 1Kg of red mud with 0.5Kg of desulfurized gypsum and 0.05Kg of concentrated sulfuric acid (98%), add water to obtain a mixed slurry, control the liquid-solid ratio of the mixed slurry to 2:1, and control the temperature to 28°C. Stirring and leaching for 0.5h; control the pH of the leaching end point to 4.5,

[0042] (2) Filtrate for 2 minutes to complete the separation of the leaching slag and the leachate, and use the leaching slag as a raw material for soil aggregates or building materials;

[0043](3) Lime (0.04kg) was added to the leaching solution, reacted at 35°C for 40 minutes, separated from solid and liquid, and the obtained filter residue was calcium sulfate, which was returned to (1) as the leaching raw material fo...

Embodiment 2

[0046] The raw material is red mud tailings from an aluminum industry in Shandong, and the main content of each component is SiO 2 : 22.78%, CaO: 35.43%, Al 2 o 3 : 4.26%, K 2 O: 0.35%, Na 2 O: 7.52%, MgO: 0.67%, Fe 2 o 3 : 7.56%.

[0047] (1) Mix 1Kg red mud with 0.6Kg phosphogypsum and 0.07Kg concentrated sulfuric acid (98%), add water to obtain a mixed slurry, control the liquid-solid ratio of the mixed slurry to 3:1, and control the temperature to 30°C. Stirring and leaching in medium temperature for 40min; control the pH of the leaching end point to be 5,

[0048] (2) Filtrate for 1 min to complete the separation of the leaching slag and the leachate, and use the leaching slag as a raw material for soil aggregates or building materials;

[0049] (3) Lime (0.05kg) was added to the leaching solution, reacted at 45°C for 30 minutes, separated from solid and liquid, and obtained filter residue was calcium sulfate, which was returned to (1) as the leaching raw material ...

Embodiment 3

[0052] The raw material is red mud tailings from an aluminum industry in Shandong, and the main content of each component is SiO 2 : 23.25%, CaO: 42.35%, Al 2 o 3 : 4.56%, K 2 O: 0.65%, Na 2 O: 1.52%, MgO: 0.92%, Fe 2 o 3 : 8.29%.

[0053] (1) Mix 1Kg red mud with 0.5Kg calcium sulfate and 0.1Kg concentrated sulfuric acid (98%), add water to obtain a mixed slurry, control the liquid-solid ratio of the mixed slurry to 5:1, and control the temperature to 25°C. Stirring and leaching in medium temperature for 30min, controlling the pH of the leaching end point to be 6, the calcium sulfate used is the calcium sulfate precipitate obtained in step (3) in Example 2.

[0054] (2) Filtrate for 0.5min to complete the separation of the leaching slag and the leachate, and the leaching slag is used as the raw material for soil aggregates or building materials;

[0055] (3) Add lime (0.1kg) to the leaching solution, react at 50°C for 30 minutes, separate solid and liquid, obtain the f...

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Abstract

The invention relates to a method for acid treatment of red mud by Bayer method to remove alkali and recover sodium, comprising the following steps: mixing red mud, gypsum, and concentrated sulfuric acid to obtain a mixture, adding water to the mixture to obtain a mixed slurry, and performing a leaching reaction on the mixed slurry, solidifying Liquid separation to obtain leaching liquid and leaching slag, add lime to the leaching liquid for reaction, solid-liquid separation, and obtain calcium sulfate and filtrate; the obtained calcium sulfate is returned for red mud leaching, and the obtained filtrate is sodium hydroxide solution, which is returned to the Bayer process as A raw material solution for extracting aluminum. The whole process realizes resource recycling. The obtained leached slag can be directly made into soil silicon fertilizer or used as a raw material for cement production to achieve zero discharge.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of solid waste, and in particular relates to a method for acid treatment of red mud by Bayer method for removing alkali and recovering sodium Background technique [0002] Red mud is a strong alkaline solid waste discharged during the production of alumina. It is called red mud because of its high iron oxide content and red color. In the Bayer process, 1 to 1.5 tons of red mud is discharged for every 1 ton of alumina produced. For sintering and combined processes, 1.5 to 2.5 tons of red mud are discharged for every 1 ton of alumina produced. As of 2015, the global stockpile of red mud has exceeded 3.5 billion tons and is increasing at a rate of 120 million tons per year. At present, my country's annual red mud discharge reaches 60 million tons, and the total red mud stockpile exceeds 600 million tons. [0003] The ecological disposal and resource utilization of red mud has alw...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/06C01D1/20C04B7/24C05D9/00
CPCC01D1/20C01F7/06C01F7/066C04B7/24C05D9/00Y02P40/10
Inventor 王丽吕斐高建德孙宁孙伟胡岳华
Owner CENT SOUTH UNIV
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