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| Study on Leaching Kinetics of Sodium Fluoride in Waste Cathodes of Aluminum Reduction Cells |
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Received:October 22, 2020
Revised:October 31, 2020
Accepted:November 02, 2020
Published Online:January 21, 2021
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| DOI：doi：10.3969/j.issn.1007-7545.2021.02.015 |
| KeyWord:waste cathode carbon block; sodium fluoride; leaching kinetics; apparent activation energy |
| Author | Institution |
| Liu Feng-qin |
北京科技大学冶金与生态工程学院 |
| Yang Xin |
北京科技大学冶金与生态工程学院 |
| Zhang Yong-jun |
平罗中兴碳素有限公司 |
| Li Rong-bin |
北京科技大学冶金与生态工程学院 |
| Li Ai-jie |
北京科技大学冶金与生态工程学院 |
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| Abstract: |
| Waste cathode carbon block is a hazardous solid waste produced during overhaul of aluminum electrolytic cells. It contains a large amount of soluble fluoride due to long-term erosion of electrolyte. Storage or landfill treatment will cause serious environmental pollution. Leaching kinetics of sodium fluoride in waste cathode carbon block was studied to reveal influence of temperature, particle size, and L/S on sodium fluoride leaching rate. The results show that soluble fluorine leaching rate is 98.9% when L/S is 25 mL/g, temperature is 85 ℃, and particle size is 0.058—0.075 mm, time is 1 hour. Soluble fluorine content in leaching residue is 83.53 mg/L, which is lower than that of the safety emission standard of 100 mg/L, and realizes harmless treatment of waste cathode carbon blocks. Leaching process conforms to shrinking core model of diffusion control in solid film with apparent activation energy of 8.97 kJ/mol. |
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