Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier
Chloride ions in zinc refining accelerate equipment corrosion and anode and cathode losses, increase lead content, and reduce zinc quality. Therefore, the removal of chloride ions has become a research priority. The existing copper slag dechlorination process has problems such as the solid film barr...
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MDPI AG
2025-05-01
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| author | Rui Li Ailin Wen Jing Li |
| author_facet | Rui Li Ailin Wen Jing Li |
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| collection | DOAJ |
| description | Chloride ions in zinc refining accelerate equipment corrosion and anode and cathode losses, increase lead content, and reduce zinc quality. Therefore, the removal of chloride ions has become a research priority. The existing copper slag dechlorination process has problems such as the solid film barrier leading to impeded mass transfer, product wrapping triggering active site coverage, and incomplete reactions due to insufficient reaction-driving force, leading to low utilization of copper slag, poor dechlorination efficiency, and long reaction times. To address these issues, a new method of deep dechlorination based on the reduction of Cu<sup>2+</sup> by liquid-phase mass transfer is proposed in this paper. The process utilizes ascorbic acid as a reducing agent, establishes a homogeneous aqueous phase reaction system, breaks through the solid membrane barrier, and avoids the encapsulation of the product layer, achieving efficient dechlorination. The enol structure of ascorbic acid promotes rapid dechlorination through proton-coupled electron transfer (PCET). Thermodynamic calculations show that compared to the current copper slag dechlorination process, this method increases the reaction-driving force by 18.6%, reduces the Gibbs free energy (ΔG<sup>θ</sup>) by 59.3%, and increases the equilibrium constant by 6.7 × 10<sup>9</sup> times, making the reaction more complete and achieving a higher degree of purification. The experimental results show that under optimized conditions, the chloride ion concentration in the solution decreases from 1 g/L to 0.0917 g/L within 20 min, with a removal rate of 90.8%. The main precipitate is CuCl. This process provides a more efficient solution to the chloride ion contamination problem in the hydrometallurgical zinc refining process. |
| format | Article |
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| institution | DOAJ |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-05-01 |
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| spelling | doaj-art-3dc914218fb840eaaf00a5326c34ea302025-08-20T03:14:42ZengMDPI AGApplied Sciences2076-34172025-05-011510567310.3390/app15105673Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film BarrierRui Li0Ailin Wen1Jing Li2Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaFaculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaFaculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, ChinaChloride ions in zinc refining accelerate equipment corrosion and anode and cathode losses, increase lead content, and reduce zinc quality. Therefore, the removal of chloride ions has become a research priority. The existing copper slag dechlorination process has problems such as the solid film barrier leading to impeded mass transfer, product wrapping triggering active site coverage, and incomplete reactions due to insufficient reaction-driving force, leading to low utilization of copper slag, poor dechlorination efficiency, and long reaction times. To address these issues, a new method of deep dechlorination based on the reduction of Cu<sup>2+</sup> by liquid-phase mass transfer is proposed in this paper. The process utilizes ascorbic acid as a reducing agent, establishes a homogeneous aqueous phase reaction system, breaks through the solid membrane barrier, and avoids the encapsulation of the product layer, achieving efficient dechlorination. The enol structure of ascorbic acid promotes rapid dechlorination through proton-coupled electron transfer (PCET). Thermodynamic calculations show that compared to the current copper slag dechlorination process, this method increases the reaction-driving force by 18.6%, reduces the Gibbs free energy (ΔG<sup>θ</sup>) by 59.3%, and increases the equilibrium constant by 6.7 × 10<sup>9</sup> times, making the reaction more complete and achieving a higher degree of purification. The experimental results show that under optimized conditions, the chloride ion concentration in the solution decreases from 1 g/L to 0.0917 g/L within 20 min, with a removal rate of 90.8%. The main precipitate is CuCl. This process provides a more efficient solution to the chloride ion contamination problem in the hydrometallurgical zinc refining process.https://www.mdpi.com/2076-3417/15/10/5673chloride removalascorbic acidliquid phase reduction |
| spellingShingle | Rui Li Ailin Wen Jing Li Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier Applied Sciences chloride removal ascorbic acid liquid phase reduction |
| title | Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier |
| title_full | Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier |
| title_fullStr | Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier |
| title_full_unstemmed | Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier |
| title_short | Research on a Reductive Deep Chlorine Removal Process for Breaking Through the Solid Film Barrier |
| title_sort | research on a reductive deep chlorine removal process for breaking through the solid film barrier |
| topic | chloride removal ascorbic acid liquid phase reduction |
| url | https://www.mdpi.com/2076-3417/15/10/5673 |
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