Zinc recovery from hazardous construction wastes via an integrated process of the air classification,alkaline leaching,and water washing |
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| Authors: | Qiang Li Youcai Zhao Kefu Liu |
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| Affiliation: | 1. School of Information Science and Technology, Fudan University, Shanghai, China Sinochem E&T Environment Engineering (Shanghai) Co., Ltd, Shanghai, China;2. School of Environmental Science and Engineering, Tongji University, Shanghai, China;3. School of Information Science and Technology, Fudan University, Shanghai, China |
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| Abstract: | Zinc- and lead-containing wastes are often mixed with construction and demolition wastes in many factories, generating abundant of heavy metal-enriched hazardous waste. In the present study, a novel integrated process of air classification, alkaline leaching, and water washing dechlorination was proposed for the efficient recycling of Zinc (Zn) resources. The first air classification process was realized via venturi tube, wherein the content of Zn could increase by 20 wt.%. After that, the product underwent an alkaline leaching process. Results showed that Zn recovery rate increased with fine particle sizes, and a 65% recovery rate was obtained under the following conditions of 5 mol/L NaOH, liquid/solid 10:1, and leaching time 1 h. Finally, water washing associated with microwave and ultrasonic treatments could remove over 85% of Cl and other water-soluble salts. All the results indicated that the integrated method had an excellent recovery rate for Zn resources from construction and demolition wastes. |
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| Keywords: | air classification alkaline leaching industrial construction and demolition wastes zinc and lead |
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