Efficient recovery of highly pure CaF 2 from fluorine-containing wastewater using an icy lime solution.

Autor: Cao S; Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China., Li Y; Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China E-mail: yubiao.li@whut.edu.cn., Wu X; Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China., Li W; Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China., Yang X; Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan, Hubei 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, Hubei 430070, China.
Jazyk: angličtina
Zdroj: Water science and technology : a journal of the International Association on Water Pollution Research [Water Sci Technol] 2024 Jul; Vol. 90 (1), pp. 32-44. Date of Electronic Publication: 2024 Jun 18.
DOI: 10.2166/wst.2024.211
Abstrakt: Developing a feasible and low-cost strategy for the recovery of calcium fluoride efficiently from fluoride-containing wastewater is very essential for the recycle of fluoride resources. Herein, a modified lime precipitation method was employed to recover CaF 2 from fluorinated wastewater using a special icy lime solution. Intriguingly, the highest F - removal was greater than 95% under the optimal condition, leaving a fluoride concentration from 200 to 8.64 mg/L, while the lime dosage was much lower than that of industry. Importantly, spherical-shaped CaF 2 particles with a 93.47% purity and size smaller than 600 nm were recovered, which has a high potential for the production of hydrofluoric acid. Besides, the precipitation was significantly affected by Ca/F molar ratio, stirring time, temperature, and solution pH. Furthermore, the thermodynamics and kinetics were investigated in detail to reveal the crystallization process. As a result, the defluorination reaction followed the pseudo-second order reaction kinetics model. Also, CO 2 in the air adversely influenced the CaF 2 purity. Based on this facile method, a high lime utilization efficiency was applied to defluorination, which contributed to protecting the environment and saving costs. This study, therefore, provides a feasible approach for the green recovery of fluorine resources and has significance for related research.
Competing Interests: The authors declare there is no conflict.
(© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)
Databáze: MEDLINE
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