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Method for removing zirconium, zinc and chromium in red mud

A red mud removal rate technology, applied in the field of zinc and chromium, and zirconium removal in red mud, can solve the problems of low pH value of solution, heavy metal removal from red mud, poor selectivity, etc., and achieve high pH value of waste liquid, heavy metal removal The effect of high removal rate and low drug consumption

Active Publication Date: 2017-02-01
HENAN POLYTECHNIC UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the heavy metals in it restrict its efficient and comprehensive utilization, so it is necessary to remove heavy metals
[0003] At present, there is no research specifically on the removal of heavy metals from red mud. The research on the removal of heavy metals from other soils or solid wastes mostly uses hydrochloric acid, sulfuric acid, oxalic acid, and citric acid as leaching solvents (Huang Chuan, Li Liu, Huang Shan, et al. et al. Study on mixed leaching of heavy metal contaminated soil with oxalic acid and EDTA[J]. Journal of Environmental Engineering, 2014, 8(8): 3480-3486; Research on the effect of lifting [J]. Journal of Environmental Science, 2015, 35(8): 2573-2581; Zhao Youcai, Xie Tian, ​​Gao Xiaofeng, etc. A method to stabilize construction waste polluted by various heavy metals. Chinese invention patent: CN 104190692 A; Zhao Youcai, Gao Xiaofeng, Xie Tian, ​​etc. A treatment method for high-concentration heavy metal polluted construction waste. Chinese invention patent: CN 103978013 A)
Using inorganic acids such as hydrochloric acid to remove heavy metals has the characteristics of high removal efficiency, but the tailings after treatment are highly acidic, and subsequent treatment of waste liquid is difficult
Using oxalic acid and EDTA to remove heavy metals has problems such as low heavy metal removal rate, poor selectivity, low concentration of heavy metals in the removal solution and low pH value of the solution, difficult treatment of the removal solution, and difficulty in the treatment of organic matter such as EDTA remaining in the tailings.

Method used

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  • Method for removing zirconium, zinc and chromium in red mud

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add the malic acid solid into the acetic acid solution at a mass percentage of 5%~10%, stir for 120~140min at a temperature of 30°C and a stirring intensity of 300r / min, and obtain a mixed acid after stirring and dissolving completely; Mix the mud with the mixed acid, stir and dissolve under the condition that the mass ratio of liquid to solid is 2~8:1. The dissolution process is 40℃, stirring time 120~210min and stirring intensity 100r / min. After the stirring is completed, the slurry Press filtration to obtain waste liquid and tailings. The removal rate of zirconium is 99.5%, the removal rate of zinc is greater than 99%, and the removal rate of chromium is greater than 99%. The tailings can be directly transported by belt to the tailings dam for storage, and after natural air drying The obtained qualified tailings can be used to prepare construction materials and also be used as a soil conditioner. The waste liquid can be used to return to dissolve the next batch of re...

Embodiment 2

[0026] Add the malic acid solid into the acetic acid solution at a mass percentage of 10%~15%, stir for 140~160min at a temperature of 40°C and a stirring intensity of 400r / min, and obtain a mixed acid after stirring and dissolving completely. Then mix the red mud with the mixed acid, stir and dissolve under the condition that the liquid-solid mass ratio is 8~14:1. After the end, the slurry is press-filtered to obtain waste liquid and tailings. The removal rate of zirconium is 99.7%, the removal rate of zinc is greater than 99.2%, and the removal rate of chromium is greater than 99.3%. The tailings can be directly transported to the tailings dam through the belt for storage. Qualified tailings can be obtained after natural air drying, which can be used to prepare building materials, and can also be used as a soil conditioner. The waste liquid can be used to return to dissolve the next batch of red mud. The dissolution process is that the volume ratio of the waste liquid to the...

Embodiment 3

[0028]The malic acid solid is added to the acetic acid solution at a mass percentage of 15%~20%, stirred for 160~180min at a temperature of 20~40°C and a stirring intensity of 450r / min, and the mixed acid is obtained after stirring and dissolving completely. Then mix the red mud with the mixed acid, stir and dissolve under the condition that the liquid-solid mass ratio is 14~20:1. After the end, the slurry is press-filtered to obtain waste liquid and tailings. The removal rate of zirconium is 99.9%, the removal rate of zinc is greater than 99.5%, and the removal rate of chromium is greater than 99.5%. The tailings can be directly transported to the tailings dam through the belt for storage. Qualified tailings can be obtained after natural air drying, which can be used to prepare building materials, and can also be used as a soil conditioner. The waste liquid can be used to return to dissolve the next batch of red mud. The dissolution process is that the volume ratio of the was...

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Abstract

The invention discloses a method for removing zirconium, zinc and chromium in red mud. The method includes the steps that malic acid and acetic acid are mixed at first to be prepared into mixed organic acid, and then the mixed acid and the red mud are mixed and stirred; qualified tailings and waste liquor are obtained after filter pressing; and when heavy metal of the waste liquor is removed through recycle leaching until the pH value of the liquor is larger than 6, quick lime is added into the waste liquor for stirring, and a qualified solution can be obtained after filtering. The zirconium content in the qualified tailings is lower than 10 mg / kg, the chromium content is smaller than 5 mg / kg, the zinc content is smaller than 1 mg / kg, the residual organic acid can achieve biodegradation, harm to people, livestock and plants is avoided, and thus the qualified tailings can be used as a modifying agent for alkaline soil. The pH value of the qualified solution is 7-8.5, and the concentration of the zirconium, chromium and zinc is lower than 0.02 mg / L. The mixed organic acid is used for removing heavy metal in the red mud, and hence the method has the characteristics that chemical consumption is small, the removal rate of the heavy metal is high, the tailings can be used directly after treatment, the waste liquor can be recycled, the pH value of the waste liquor is high, the heavy metal content of the waste liquor is high and treatment and recycling of the waste liquor are easy.

Description

technical field [0001] The invention relates to the technical field of red mud comprehensive treatment, in particular to a method for removing zirconium, zinc and chromium in red mud. Background technique [0002] Bayer process red mud is the tailings produced during the process of smelting alumina from bauxite using the Bayer process. It is a strong alkaline solid pollutant containing various heavy metals such as zirconium, zinc and chromium. body and soil pollution. In addition, Bayer process red mud can be used as raw materials for extracting rare and precious metals and preparing building materials and environmental adsorption materials (Zhu Guohai, Wang Keqin, Wang Hao, et al. Research on the recovery of titanium dioxide from sulfuric acid leaching red mud slag[J]. Nonferrous Metals (Smelting Part), 2012, 7: 23-26; Nan Xiangli, Zhang Tingan, Liu Yan, etc. Analysis of Comprehensive Utilization of Red Mud in my country [J]. Journal of Process Engineering, 2010, 10(S1): 23...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00
CPCB09B3/00
Inventor 朱晓波李望汤森李文中张乾张玉德邢宝林张传祥陆银平
Owner HENAN POLYTECHNIC UNIV
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