{"title":"Gradient Separation and Recovery of Pb, Se, Cu, and Hg from Acid Sludge by a Sustainable Hydrometallurgical Process","authors":"Xuexian Jiang, Wenyun Zhu, Wei Liu, Guixiang He, Tao Wei, Yongming Yang, Zhonglin Li, Changmao Liao, Cheng Li, Weiguang Zhang, Yibing Li, Xuejiao Cao","doi":"10.1007/s40831-024-00892-5","DOIUrl":null,"url":null,"abstract":"<p>Acid sludge, a by-product of the Cu smelting process rich in Pb, Se, Cu, Hg, and other valuable metals, is a highly recyclable smelting material. Due to its high selenium content and various phase structures that form inter-chemical and inclusion structures with associated minerals such as copper and mercury, selective separation and recovery of Pb, Cu, Se, Hg and other components are limited. To address this problem, a cascade separation process of “H<sub>2</sub>SO<sub>4</sub> + NaClO<sub>3</sub> oxidized coordinated leaching—HCl and Na<sub>2</sub>SO<sub>3</sub> selective reduction of selenium—H<sub>2</sub>C<sub>2</sub>O<sub>4</sub> reduction of copper precipitation—NaH<sub>2</sub>PO<sub>2</sub> reduction of mercury precipitation” was used for the efficient recovery of these metals from acidic sludge. The results showed that excellent outcomes have been obtained under optimal process parameters at each stage. In the oxidation leaching stage, Pb remains in the slag, Se, Cu, and Hg are leached into the solution, and the leaching rate is above 99%. Under appropriate concentrations of hydrochloric acid, Se was selectively separated in a complexation reaction with Na<sub>2</sub>SO<sub>3</sub>. The precipitation rate for Se was almost 100%, with Se product purity reaching up to 99.4%. After that, the precipitation rate of Cu in the oxalic acid precipitation is more than 99%, and the precipitation rate of Hg in the sodium hypophosphite reduction process is more than 99%. In addition, 99.09% of total lead, 97.64% of total selenium, 98.97% of total copper and 98.08% of total mercury in the acid sludge entered their separation products. During the process, the acid sludge's metals are effectively separated without introducing difficult impurity ions.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\n","PeriodicalId":17160,"journal":{"name":"Journal of Sustainable Metallurgy","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Sustainable Metallurgy","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1007/s40831-024-00892-5","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Acid sludge, a by-product of the Cu smelting process rich in Pb, Se, Cu, Hg, and other valuable metals, is a highly recyclable smelting material. Due to its high selenium content and various phase structures that form inter-chemical and inclusion structures with associated minerals such as copper and mercury, selective separation and recovery of Pb, Cu, Se, Hg and other components are limited. To address this problem, a cascade separation process of “H2SO4 + NaClO3 oxidized coordinated leaching—HCl and Na2SO3 selective reduction of selenium—H2C2O4 reduction of copper precipitation—NaH2PO2 reduction of mercury precipitation” was used for the efficient recovery of these metals from acidic sludge. The results showed that excellent outcomes have been obtained under optimal process parameters at each stage. In the oxidation leaching stage, Pb remains in the slag, Se, Cu, and Hg are leached into the solution, and the leaching rate is above 99%. Under appropriate concentrations of hydrochloric acid, Se was selectively separated in a complexation reaction with Na2SO3. The precipitation rate for Se was almost 100%, with Se product purity reaching up to 99.4%. After that, the precipitation rate of Cu in the oxalic acid precipitation is more than 99%, and the precipitation rate of Hg in the sodium hypophosphite reduction process is more than 99%. In addition, 99.09% of total lead, 97.64% of total selenium, 98.97% of total copper and 98.08% of total mercury in the acid sludge entered their separation products. During the process, the acid sludge's metals are effectively separated without introducing difficult impurity ions.
期刊介绍:
Journal of Sustainable Metallurgy is dedicated to presenting metallurgical processes and related research aimed at improving the sustainability of metal-producing industries, with a particular emphasis on materials recovery, reuse, and recycling. Its editorial scope encompasses new techniques, as well as optimization of existing processes, including utilization, treatment, and management of metallurgically generated residues. Articles on non-technical barriers and drivers that can affect sustainability will also be considered.