CENSE, Department of Sciences and Environmental Engineering, School of Science and Technology, NOVA University Lisbon, Caparica Campus, 2829-516 Caparica, Portugal; CERIS and Department of Civil Engineering, School of Science and Technology, NOVA University Lisbon, Caparica Campus, 2829-516 Caparica, Portugal.
LAQV@REQUIMTE, Department of Chemistry, School of Science and Technology, NOVA University Lisbon, Caparica Campus, 2829-516 Caparica, Portugal.
Sci Total Environ. 2020 Mar 25;710:136364. doi: 10.1016/j.scitotenv.2019.136364. Epub 2019 Dec 30.
Tungsten is a critical raw material for European and U.S. economies. Tungsten mine residues, usually considered an environmental burden due to e.g. arsenic content, are also secondary tungsten resources. The electrodialytic (ED) process and deep eutectic solvents (DES) have been successfully and independently applied for the extraction of metals from different complex environmental matrices. In this study a proof of concept demonstrates that coupling DES in a two-compartment ED set-up enhances the removal and separation of arsenic and tungsten from Panasqueira mine secondary resources. Choline chloride with malonic acid (1:2), and choline chloride with oxalic acid (1:1) were the DES that in batch extracted the average maximum contents of arsenic (16%) and tungsten (9%) from the residues. However, when ED was operated at a current intensity of 100 mA for 4 days, the extraction yields increased 22% for arsenic and 11% for tungsten, comparing to the tests with no current. From the total arsenic and tungsten extracted, 82% and 77% respectively were successfully removed from the matrix compartment, as they electromigrated to the anolyte compartment, from where these elements can be further separated. This achievement potentiates circular economy, as the final treated residue could be incorporated in construction materials production, mitigating current environmental problems in both mining and construction sectors.
钨是欧洲和美国经济的关键原材料。钨矿残渣通常由于砷含量等原因而被视为环境负担，但也是二次钨资源。电渗析（ED）过程和深共晶溶剂（DES）已成功且独立地应用于从不同复杂环境基质中提取金属。在这项研究中，概念验证表明，在双室 ED 装置中耦合 DES 可以增强从 Panasqueira 矿山二次资源中去除和分离砷和钨。氯化胆碱与丙二酸（1:2）和氯化胆碱与草酸（1:1）是在批处理中从残渣中提取平均最大含量为 16%的砷（16%）和 9%的钨（9%）的 DES。然而，当 ED 在 100 mA 的电流强度下运行 4 天时，与无电流的测试相比，砷的提取率增加了 22%，钨的提取率增加了 11%。从提取的总砷和总钨中，分别有 82%和 77%成功地从基质室中去除，因为它们通过电迁移到阳极室，从那里可以进一步分离这些元素。这一成就推动了循环经济，因为最终处理后的残渣可以被纳入建筑材料生产中，从而缓解当前矿业和建筑部门的环境问题。
