Reactive extraction of sodium hydroxide from alkali solutions for the separation of sodium and aluminum — Part I. Effect of extractant

Zhang, Ying; Zheng, Shili; Wang, Xiaohui; Du, Hao; Fang, Zhigang Zak; Zhang, Yi

doi:10.1016/j.hydromet.2015.03.013

Cited by 6 publications

(2 citation statements)

References 16 publications

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“…In addition, leaching and recovering alkali from red mud has also been widely investigated, such as the soda-lime roasting process, solvent extraction process, calcification-carbonation method, and water leaching and hydro-chemical process [8,[18][19][20]. The addition of lime has been widely studied because of its excellent performance in replacing Na 2 O, as well as its abundance and cheapness.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

et al. 2019

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Recovering alkali from Bayer red mud is crucial for storage security, resource utilization and environmental protection. In this study, the addition of MgO and/or CaO was conducted to recover alkali from red mud with a hydrothermal method for the first time. A synergistic result with a residual Na2O/SiO2 weight ratio of 0.03 was obtained by adding the blend of CaO and MgO at an appropriate temperature. MgO was found to be more temperature-dependent than CaO when substituting Na2O from red mud due to their different hydration processes. The alkali recovery was controlled by a reaction at a temperature of <200 °C and by internal diffusion at a higher temperature for MgO, but controlled by internal diffusion for CaO in the whole temperature range studied. The formation of hydrotalcite-like compounds with a loose structure was verified with the help of XRD, FTIR, and SEM-EDS. It was proved that both the reaction kinetics and the characteristics of solid products have a significant influence on the recovery of alkali.

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Section: Introductionmentioning

confidence: 99%

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

et al. 2019

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“…Under optimal conditions, the red mud was disposed by the hydrothermal process and the Na 2 O content and Al 2 O 3 /SiO 2 (A/S) in leached Fe‐rich red mud reached 0.5 wt% and 0.3, respectively . Generation of silicate hydrogarnet during digestion of bauxite was studied but owing to addition of lime, the sodium content in red mud decreased significantly . When red mud was mixed with hydrated lime and processed by digestion, hydrothermal treatment, calcination, and leaching with soda liquids, the recovery rate of Na 2 O was as high as 90%…”

Section: Introductionmentioning

confidence: 99%

Dealkalization of Red Mud by Carbide Slag and Flue Gas

Wang

Zhang

Liu

et al. 2018

CLEAN Soil Air Water

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Red mud and carbide slag which are industrial waste materials from alumina and chlor‐alkali plants pose environmental risks due to the large production volume. However, reutilization has been limited due to their composition and structure and the large alkali concentration in red mud has hampered utilization of red mud. At the same time, flue gas produced during the process of coal firing is a major environmental threat causing greenhouse effects and fog haze. In this work, alkalis (Na2O) in red mud were released by the alkali and acid methods and carbide slags and flue gas were utilized to remove alkalis from red mud. The effects of the reaction time, temperature, and solid‐to‐liquid ratio on dealkalization of red mud by carbide slag were studied. Flame absorption and X‐ray diffraction were employed to monitor the changes in the red mud before and after dealkalization. Under the optimal conditions, the residual Na2O amount in the red mud after dealkalization using the carbide slag diminished to less than 3 wt%, whereas that of Na2O dropped to less than 2 wt% using flue gas. The pH of the suspension is determined by the acid method. The hydroxysodalite (Na8Al6Si6O24(OH)2) structure in the initial red mud was destroyed and soluble sodium salts formed in the suspension can be easily replaced by carbide slag or flue gas reducing Na2O.

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Two-Stage Process for Precipitating Coarse Boehmite from Sodium Aluminate Solution

Liu

et al. 2017

JOM

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Reactive extraction of sodium hydroxide from alkali solutions for the separation of sodium and aluminum — Part I. Effect of extractant

Cited by 6 publications

References 16 publications

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

Dealkalization of Red Mud by Carbide Slag and Flue Gas

Two-Stage Process for Precipitating Coarse Boehmite from Sodium Aluminate Solution

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