Method for reducing alumina-silica ratio of red mud through multistage carbonization

An aluminum-silicon ratio, red mud technology, applied in the direction of alumina/aluminum hydroxide, etc., can solve the problems of a large amount of high-alkali red mud, increased alkali consumption, low alumina recovery rate, etc., and achieves low production energy consumption. , Low alkali content, and the effect of solving the environmental pollution caused by red mud

Active Publication Date: 2014-08-06
DONGDA NONFERROUS SOLID WASTE TECH RES INST LIAOLING CO LTD
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Problems solved by technology

[0005] Aiming at the current high-grade bauxite mines in my country that are on the verge of depletion, resulting in the low recovery rate of alumina in the existing Bayer process, increased alkali consumption, and large stockpiles of high-alkali red mud, the present invention provides a method for r

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  • Method for reducing alumina-silica ratio of red mud through multistage carbonization
  • Method for reducing alumina-silica ratio of red mud through multistage carbonization

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Embodiment 1

[0047] (1) Firstly, mix lime with medium and low-grade bauxite at a mass ratio of 0.25:1, and place them in a sodium aluminate solution with a caustic alkali concentration of 260g / L and a molar ratio of sodium oxide to aluminum oxide of 2.5 at 260°C Stirring and reacting for 15 minutes, a calcified transformation slag with hydrated calcium aluminosilicate as the main phase was obtained, and the liquid-solid ratio of the sodium aluminate solution to the solid material was 10ml:1 g;

[0048] (2) Mix the calcified transformation slag and clean water in a closed container, and pass CO2 into the closed container 2 , CO 2 The gas partial pressure is 0.1MPa, and the reaction is stirred at 160°C for 240 minutes to obtain carbide slag containing calcium carbonate, hydrated calcium silicate, aluminum hydroxide and incompletely reacted hydrated calcium aluminosilicate, and a liquid-solid mixture of clean water and calcified transformation slag The ratio is 15ml: 1 g;

[0049] (3) Mix t...

Embodiment 2

[0052] (1) First mix lime and low-grade bauxite at a mass ratio of 0.35:1, and place them in a sodium aluminate solution with a caustic alkali concentration of 140g / L and a molar ratio of sodium oxide to aluminum oxide of 3.5 at 200°C Stirring and reacting for 60 minutes, a calcified transformation slag with hydrated calcium aluminosilicate as the main phase was obtained, and the liquid-solid ratio of the sodium aluminate solution to the solid material was 3ml: 1g;

[0053] (2) Mix the calcified transformation slag and clean water in a closed container, and pass CO2 into the closed container 2 , CO 2 The gas partial pressure is 1.6MPa, stirred and reacted at 60°C for 30 minutes, and the carbide slag containing calcium carbonate, hydrated calcium silicate, aluminum hydroxide and incompletely reacted hydrated calcium aluminosilicate is obtained, and the liquid-solid mixture of clear water and calcified transformation slag is obtained. The ratio is 3ml: 1 g;

[0054] (3) Mix th...

Embodiment 3

[0057] (1) Firstly, mix lime and medium-low-grade bauxite according to the mass ratio of 0.8:1, and put them in a sodium aluminate solution with a caustic alkali concentration of 180g / L and a molar ratio of sodium oxide to aluminum oxide of 3.0 at 100°C Stirring and reacting for 40 minutes, a calcified transformation slag with hydrated calcium aluminosilicate as the main phase was obtained, and the liquid-solid ratio of the sodium aluminate solution to the solid material was 5ml: 1g;

[0058] (2) Mix the calcified transformation slag and clean water in a closed container, and pass CO2 into the closed container 2 , CO 2 The gas partial pressure is 1.2MPa, and the reaction is stirred at 110°C for 120 minutes to obtain carbide slag containing calcium carbonate, hydrated calcium silicate, aluminum hydroxide and incompletely reacted hydrated calcium aluminosilicate, and a liquid-solid mixture of clean water and calcified transformation slag The ratio is 7ml: 1 g;

[0059] (3) Mix...

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Abstract

The invention belongs to the field of bauxite resource utilization, and particularly relates to a method for reducing the alumina-silica ratio of red mud through multistage carbonization. The method comprises the following steps: at first, mixing lime with medium-low-grade aluminum-contained material, stirring in water or a sodium aluminate solution to carry out a calcification conversion reaction, and mixing the obtained calcification conversion slag with clear water or a low-concentration alkaline liquid in a closed container; introducing CO2 in the closed container to carry out calcification conversion to obtain carbide slag; mixing the alkaline liquid with the carbide slag to obtain an aluminum-contained dissolution liquid and solid slag; carrying out carbonization and aluminum dissolving on the solid slag for 1-4 times till the mass ratio of aluminum oxide to silicon oxide in red mud with a novel structure is reduced to 0.2-0.5. Alkali and aluminum are not contained in the red mud with the novel structure, the alumina-silica ratio can be reduced to be below 0.5, the content of sodium oxide in the red mud is lower than 0.6%, and the clean production of the alumina industry and the red mud utilization are realized.

Description

technical field [0001] The invention belongs to the field of utilization of bauxite resources, and in particular relates to a method for reducing the aluminum-silicon ratio of red mud through multi-stage carbonization. Background technique [0002] The Bayer process is the main process for producing alumina. In the process of producing alumina by the Bayer process, the ore undergoes processes such as crushing, high-pressure dissolution, sedimentation separation, and washing to obtain sodium aluminate solution and red mud, and the red mud is discharged as waste. or stockpile. The main phase of Bayer red mud is hydrated sodium aluminosilicate, and its molecular formula is roughly equivalent to Na 2 O·Al 2 o 3 1.7SiO2 2 · n h 2 O. Since the main phase structure of Bayer red mud is hydrated sodium aluminosilicate, two problems arise: (1) when the ore grade is low and the silica content is high, a large amount of alumina is lost; (2) oxidation in red mud The high sodium c...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 张廷安吕国志刘燕朱小峰豆志河
Owner DONGDA NONFERROUS SOLID WASTE TECH RES INST LIAOLING CO LTD
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