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| Enhanced Solidification-Desalination Integration and Application of Waste Incineration Fly Ash by Chelating Agent and Chelating Process |
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Received:March 10, 2021
Revised:March 22, 2021
Accepted:March 25, 2021
Published Online:June 29, 2021
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| DOI： |
| KeyWord:fly ash curing; chelating agent; mass transfer; pilot test |
| Author | Institution |
| Zhang Tong |
Institute of Process Engineering, Chinese Academy of Sciences |
| Zhang Jintao |
Institute of Process Engineering, Chinese Academy of Sciences |
| Gong Xuzhogn |
Institute of Process Engineering, Chinese Academy of Sciences |
| Wang Zhi |
Institute of Process Engineering, Chinese Academy of Sciences |
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| Abstract: |
| The treatment of urban waste is becoming more and more imperative with the rapid development of economy. Waste incineration power generation is the mainstream means of dealing with domestic waste. However, the fly ash produced in the process of waste incineration is very harmful for human health and ecological environment. Therefore, efficient and economical technology for fly ash solidification is urgent to prevent heavy metal leaching during landfill. Herein, efficient chelating agent was formed by phosphate and sulfide based on the principle of heavy metal mineralization and geochemistry. Significant curing effects have been achieved in the laboratory, and the heavy metal content in the fly ash leaching solution after curing is far less than the national standard. However, poor mass transfer greatly limits the chelation effect in the pilot scale-up test. The chelating method was modified to strengthen the mass transfer. The concentration of the chelating agent is diluted to 1%, and then form a slurry with the fly ash, finally plate and frame filtration or centrifugal separation are used to achieve the synergy between the solidification of heavy metals and the separation of salts. As a result, a significant solidification effect was also achieved in a 500 kg pilot test with modified chelating process. The content of 12 heavy metals in the fly ash leaching solution is far less than the national standard limit. More importantly, the potassium and sodium salts were also recovered from t fly ash. Obviously, the synergy of the compound chelating agent and the new chelating process is an efficient method to strengthen the solidification of waste incineration fly ash. |
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