Abstract
Abstract Microwave (MW) assisted chloride leaching was studied to remove valuable and heavy metals from two zinc plant residues, i.e. goethite sludge and Zn-leach product. For both materials, NaCl leaching parameters, such as temperature, NaCl concentration, leaching time and addition of acid, were optimized. For goethite sludge, the best efficiencies for Cu (45–47 %), Pb (83–90 %), and Zn (47–58 %) extraction, with a minimal dissolution of matrix elements, were obtained at 200 °C, 300 g/L NaCl and L/S 10. At short leaching times (5 min) the maximal leachability of Cu and Zn was reached, while at longer leaching time (60 min) the Pb extraction increased to 90 ± 1%. Zn leaching was limited due to the presence of stable franklinite (ZnFe2O4). NaCl (280 g/L) leaching of Zn-leach product required the addition of 1 M HCl to improve metal leaching to Ag 52 ± 3 %, Bi 83 ± 1 %, Cd 82 ± 4 %, Sb 39 ± 1 %, Zn 71 ± 2 % at 200 °C, L/S 10 for 30 min. Consequently, matrix dissolution was enhanced. Metal associations in Zn-leach product were statistically investigated. The environmental impact of the MW leached materials was evaluated by a one stage leaching test, which showed a significant overall reduction in heavy metal leachability compared to untreated materials.
Highlights
For this purpose, microwave (MW) assisted NaCl leaching was investigated as a method to selectively extract Pb and Zn from goethite sludge through the formation of soluble chloride complexes
Extended Abstract The present work focusses on the valorisation of two zinc plant residues coming from hydrometallurgical zinc production [1]: goethite sludge and Zn-leaching residue
The goethite sludge is a hazardous waste material, due to the presence of heavy metals (As, Cd, Cu, Pb and Zn) and is currently dumped on site or ponded, while the leach product is further processed by smelter industry for lead and silver recovery
Summary
Microwave (MW) assisted NaCl leaching was investigated as a method to selectively extract Pb and Zn from goethite sludge through the formation of soluble chloride complexes. Extended Abstract The present work focusses on the valorisation of two zinc plant residues coming from hydrometallurgical zinc production [1]: goethite sludge and Zn-leaching residue. The goethite sludge is a hazardous waste material, due to the presence of heavy metals (As, Cd, Cu, Pb and Zn) and is currently dumped on site or ponded, while the leach product is further processed by smelter industry for lead and silver recovery.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.