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Red-mud citric acid dealkalizing technique

A technology of citric acid and red mud, which is applied in the field of comprehensive treatment of red mud, can solve the problems of large consumption of chemicals, high liquid-solid ratio, red mud cannot be used for preparation, etc., and achieve the effect of reducing the consumption of chemicals

Active Publication Date: 2015-12-23
HENAN POLYTECHNIC UNIV
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AI Technical Summary

Problems solved by technology

At present, the red mud dealkalization process mainly includes the following methods: water immersion process (Zhang Guoli, Li Shaochun, Zhang Xinyuan, etc. "Study on the Bayer process of red mud water washing and alkali removal process", Journal of Qingdao University of Technology, 2012, 33 (4): 59 -62) There are low dealkalization rate, high alkalinity of dealkalization solution, high liquid-solid ratio, high washing times, red mud after dealkalization cannot be used as raw materials for the preparation of building materials and environmental adsorption materials
Carbon dioxide leaching process (Wang Zhi, Han Minfang, Zhang Yihe, etc. "Study on Wet Carbonization Dealkalization Process of Bayer Process Red Mud" Silicate Bulletin, 2013, 32(9):1851-1855) has low dealkalization rate and leaching Defects such as high equipment performance requirements and low activity of red mud after treatment
Hydrochloric acid leaching process (Zhong Chen, Xia Jupei, "Na in Bayer process red mud + Leaching Experimental Research of "Silicate Bulletin, 2013, 32(9): 2012-2015) there is a large amount of acid consumption in the dealkalization process, high acidity of the dealkalization liquid and strong acidity of the red mud after treatment, resulting in secondary pollution, etc. defect
Lime leaching process (Li Shaokang, Liang Chunlai, Li Guangzhu, etc. "A Bayer Red Mud Atmospheric Pressure Dealkalization Method", Invention Patent, 2004) has defects such as low dealkalization rate, large chemical consumption and high energy consumption

Method used

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  • Red-mud citric acid dealkalizing technique

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The first batch of red mud is subjected to a stirring leaching and a water washing:

[0027] The first batch of red mud and citric acid added in an amount of 12%~15% by mass of red mud are stirred and leached under the condition of a liquid-solid mass ratio of 3~5:1. The leaching process is carried out at a temperature of 30~40°C, The stirring time is 90~120min and the stirring intensity is 100~150r / min. After the stirring is completed, the ore pulp is press-filtered to obtain acidic leaching residue and acidic leaching solution. The acidic leaching solution is the primary dealkalization solution of the first batch of red mud. After washing with water, the first batch of dealkalization slag and washing liquid of red mud are obtained, and then citric acid with a mass percentage of 7% to 8% of the washing liquid is added to the washing liquid to obtain the second-stage dealkalization liquid of the first batch of red mud.

[0028] The second batch of red mud is subjected t...

Embodiment 2

[0036] The first batch of red mud is subjected to a stirring leaching and a water washing:

[0037] The first batch of red mud and citric acid added in an amount of 9%~12% by mass of red mud are stirred and leached under the condition of a liquid-solid mass ratio of 3~5:1. The leaching process is carried out at a temperature of 40~50°C, The stirring time is 90~120min and the stirring intensity is 100~150r / min. After the stirring is completed, the ore pulp is press-filtered to obtain acidic leaching residue and acidic leaching solution. The acidic leaching solution is the primary dealkalization solution of the first batch of red mud. After washing with water, the first batch of red mud dealkalization slag and washing liquid are obtained, and then citric acid with a mass percentage of 6% to 7% of the washing liquid is added to the washing liquid to obtain the second batch of red mud dealkalization liquid.

[0038] The second batch of red mud is subjected to a second stirring lea...

Embodiment 3

[0046] The first batch of red mud is subjected to a stirring leaching and a water washing:

[0047] The first batch of red mud and citric acid added in an amount of 6%~9% by mass of red mud are stirred and leached under the condition of a liquid-solid mass ratio of 3~5:1. The leaching process is carried out at a temperature of 50~60°C, The stirring time is 90~120min and the stirring intensity is 100~150r / min. After the stirring is completed, the ore pulp is press-filtered to obtain acidic leaching residue and acidic leaching solution. The acidic leaching solution is the primary dealkalization solution of the first batch of red mud. After washing with water, the first batch of red mud dealkalization slag and washing liquid are obtained, and then citric acid with a mass percentage of 5% to 6% of the washing liquid is added to the washing liquid to obtain the first batch of red mud secondary dealkalization liquid.

[0048] The second batch of red mud is subjected to a second stir...

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Abstract

The invention discloses a red-mud citric acid dealkalizing technique. According to the technique, citric-acid three-level cross-flow dealkalizing operation is carried out on red mud, and Bayer-process red mud is dealkalized through citric acid. Due to the fact that the citric acid is organic tribasic acid, sodium and potassium in the red mud can be effectively removed under the condition of the lower citric acid using amount and the low temperature, the pH value of the dealkalized sludge ranges from 6.5 to 7.5, and the dealkalized sludge can be dammed and piled. Residual citric acid in the dealkalized sludge of the red mud can be degraded biologically, has a repairing function on alkaline soil and can serve as a modifying agent for the alkaline soil. The citric acid can generate calcium citrate sediment with other elements like calcium, so that calcium can be solidly stored in the dealkalized sludge of the red mud to be used as raw materials for manufacturing building materials. Elements like titanium, scandium and rare earth are difficult to dissolve out, the taste of the elements in the dealkalized sludge of the red mud is improved, and the dealkalized sludge can be used as raw materials to extract valuable rare metal. According to the red-mud citric acid dealkalizing technique, the citric acid can be recycled, and the consumption of chemical agents is reduced. In addition, the pH value of obtained dealkalized liquid ranges from 6.5 to 7.5, the dealkalized liquid does not contain heavy metal ions, and the dealkalized liquid can be drained and utilized.

Description

technical field [0001] The invention relates to the technical field of red mud comprehensive treatment, in particular to a red mud citric acid dealkalization process. Background technique [0002] Bayer process red mud is the tailings produced in the Bayer process of aluminum smelting. It is a strong alkaline solid pollutant, and its storage process will cause groundwater and soil pollution. In addition, the high alkali content in red mud is a key factor restricting the extraction of valuable rare metals from red mud, the preparation of building materials and environmental adsorption materials, so effective measures must be taken to deal with this type of solid waste. At present, the red mud dealkalization process mainly includes the following methods: water immersion process (Zhang Guoli, Li Shaochun, Zhang Xinyuan, etc. "Study on the Bayer process of red mud water washing and alkali removal process", Journal of Qingdao University of Technology, 2012, 33 (4): 59 -62) There...

Claims

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Application Information

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IPC IPC(8): B03B7/00
CPCB03B7/00
Inventor 朱晓波李望管学茂张乾陆银平张玉德
Owner HENAN POLYTECHNIC UNIV
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