Staged leaching behavior of red mud during dealkalization with mild acid

Hu, Guangyan; Lyu, Fei; Khoso, Sultan Ahmed; Zeng, Hua; Sun, Wei; Tang, Honghu; Wang, Li

doi:10.1016/j.hydromet.2020.105422

Cited by 29 publications

(16 citation statements)

References 25 publications

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“…46 The alkali and calcium ions exposed by sodium and calcium ions can react quickly with the acid solution. 47 Therefore, the alkali reduction rate of RM and the concentration of calcium ions in the leaching solution change the fastest within 10 min. Hydrogen ions preferentially react with calcite in RM to form gypsum, and part of calcite reacts with hydrogen ions to release calcium ions (eqs 2 and 3).…”

Section: Resultsmentioning

confidence: 99%

Dealkalization and Leaching Behavior of Fe, Al, Ca, and Si of Red Mud by Waste Acid from Titanium White Production

et al. 2021

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Dealkalization is the necessary step for the multipurpose use of red mud (RM), and acid leaching is a productive method to realize the dealkalization of RM. Most researches focus on recovering metals from the highly alkaline waste by pure acid leaching or stabilization by dealkalization. In this study, according to the strong alkalinity of RM and strong acidity of the waste acid from titanium dioxide production, the waste acid was used for the dealkalization of RM. The effects of leaching temperature, reaction time, the concentration of waste acid, liquid–solid ratio (L/S), and stirring rate on the dealkalization of RM were investigated, and the main metal ions in the dealkalization solution were analyzed. The results show that the leaching ratio of sodium can reach 92.3591% when the leaching temperature is 30 °C, the reaction time is 10 min, the concentration of waste acid is 0.6238 mol/L, the L/S is 4:1, and the stirring rate is 300 rpm. The residual alkali content in the treated RM is 0.2674%, which is a reduction to less than 1%. The phase analysis results show that the sodalite and cancrinite in RM are dissolved, decomposed, and transformed after acid leaching. Therefore, RM meets the requirements of building materials after dealkalization, which provides further development as building material products.

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Section: Resultsmentioning

confidence: 99%

Dealkalization and Leaching Behavior of Fe, Al, Ca, and Si of Red Mud by Waste Acid from Titanium White Production

et al. 2021

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“…As is shown in Figure 3b, the mineral composition of the red mud sample included 51.74 ± 0.35% hydrated andradite, 21.71 ± 0.21% calcite, 21.46 ± 0.05% hydrated sodalite, and 5.09 ± 0.05% hematite. The hydrated sodalites is the main alkaline component that accounts for the great potential of alkali production in red mud [66]. According to Table 3, the chemical composition of coal gangue was mainly SiO2 and Al2O3 with contents of 49.81 ± 0.06% and 24.82 ± 0.13%, respectively.…”

Section: Properties Of Materialsmentioning

confidence: 99%

“…This indicates that the addition of red mud can effectively alleviate the AMD generated from the coal gangue. The AMD is neutralized by the alkaline component in red mud as described by Equations (10)-(17) [66].…”

Section: Mass Ratio Ph Valuementioning

confidence: 99%

Co-Disposal of Coal Gangue and Red Mud for Prevention of Acid Mine Drainage Generation from Self-Heating Gangue Dumps

2020

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The seepage and diffusion of acid mine drainage (AMD) generated from self-heating coal gangue tailings caused acid pollution to the surrounding soil and groundwater. Red mud derived from the alumina smelting process has a high alkali content. To explore the feasibility of co-disposal of coal gangue and red mud for prevention of AMD, coal gangue and red mud were sampled from Yangquan (Shanxi Province, China), and dynamic leaching tests were carried out through the automatic temperature-controlled leaching system under the conditions of different temperatures, mass ratios, and storage methods. Our findings indicated that the heating temperature had a significant effect on the release characteristics of acidic pollutants derived from coal gangue, and that the fastest rate of acid production corresponding to temperature was 150 °C. The co-disposal dynamic leaching tests indicated that red mud not only significantly alleviated the release of AMD but also that it had a long-term effect on the treatment of acid pollution. The mass ratio and stacking method were selected to be 12:1 (coal gangue: red mud) and one layer was alternated (coal gangue covered with red mud), respectively, to ensure that the acid-base pollution indices of leachate reached the WHO drinking-water quality for long-term discharge. The results of this study provided a theoretical basis and data support for the industrial field application of solid waste co-treatment.

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“…On the other hand, RM contains several interesting minor or trace elements, including rare earth elements (REEs) 13, 14, of which gallium (60–80 g t −1 ), yttrium (60–150 g t −1 ), uranium (50–60 g t −1 ), and thorium (20–30 g t −1 ) are the most common 15. Given the significant rise in the price of REEs and RE metal oxides, which began at $300 per kilogram in 2010 and rose to $3600 per kilogram in 2011, RM has been extensively researched for the recovery of these important elements 16.…”

Section: Introductionmentioning

confidence: 99%

“…REEs can be present in bauxite as mineral phases, as ions absorbed on mineral surfaces, or replace comparable ions in the lattice of some matrix minerals. Some literature data on the leaching of REEs from bauxite residues are available 4, 10–13, 15, 16. There are also some literature data on the leaching of REEs from bauxite residues 10, 19, 21–23, 26–30.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Recovery of Rare Earth Elements from Red Mud

et al. 2021

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An overview of methods used to enhance the recovery of rare earth elements (REEs) from bauxite residue or red mud (RM) is given. RM is a byproduct of the Bayer alumina production process. The composition of RM depends on the bauxite source and digestion protocol. This study aimed at developing and improving technological steps to recover REEs such as Sc, La, and Y from RM. Parameters such as leaching agent, contact time, temperature, and solid‐to‐liquid ratio were investigated to achieve optimum REE recovery from RM by combining hydrometallurgical steps such as acid digestion, ion exchange, and solvent extraction. The process was selected by considering its efficiency for selective recovery of Sc, La, and Y and suitability for subsequent solvent extraction and ion exchange of the leaching solution to separate the individual REEs.

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Staged leaching behavior of red mud during dealkalization with mild acid

Cited by 29 publications

References 25 publications

Dealkalization and Leaching Behavior of Fe, Al, Ca, and Si of Red Mud by Waste Acid from Titanium White Production

Dealkalization and Leaching Behavior of Fe, Al, Ca, and Si of Red Mud by Waste Acid from Titanium White Production

Co-Disposal of Coal Gangue and Red Mud for Prevention of Acid Mine Drainage Generation from Self-Heating Gangue Dumps

Enhancing the Recovery of Rare Earth Elements from Red Mud

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