Abstract
The imbalance between raw materials of high economic importance and their supply has increased the search for new approaches to obtain valuable elements from mining tailings. In this study, the extraction of copper, zinc, and lead from sulfidic tailing in sulfate–chloride media was investigated. A 33 Box–Behnken design was applied to evaluate three variables over a 4-h testing period: sulfuric acid concentration (0.01–1.0 mol/L H2SO4), sodium chloride (10–60 g/L NaCl), and temperature (20–70 °C). The design showed two optimum working regions: a combination of a high NaCl level, low H2SO4 level, and medium temperature level for lead leaching, while for copper and zinc, a combination of a medium–high H2SO4 level and a high temperature level. The concentration of NaCl had only a slight impact on their leaching. Based on these results, two-stage leaching was performed. The first stage was carried out under an experimental condition that favored the leaching of lead (60 g/L NaCl, 0.01 mol/L H2SO4, 45 °C, 1 h, 10:1 liquid-to-solid ratio), whereas the second stage maximized the leaching of copper and zinc (60 g/L NaCl, 0.5 mol/L H2SO4, 70 °C, 24 h, 10:1 liquid-to-solid ratio). The global leaching rate was 66.8 ± 3.0% copper, 84.1 ± 5.2% zinc, and 93.9 ± 3.2% lead. The iron and arsenic content were also leached by about 20 and 50% at the end of the second stage. The study demonstrated that the use of sulfate–chloride media in a two-stage leaching considerably improved the extraction of the desired metals and was, therefore, suitable for their recovery.Graphical
Highlights
The increasing economic importance of different industrial sectors, such as modern technology, has led to a growing demand for the production and extraction of metals.1 3 Vol.:(0123456789)Journal of Sustainable Metallurgythere is an imbalance between some metal supplies and world demand [1] due to the reduction of primary resources and high-grade ores [2, 3]
The pH was adjusted to ≤ 2.0 with H2SO4 (95.0–98.0%) at the beginning of the experiments, but only in conditions where the pH was higher than 2.0
Analysis of the solid residues by XRD analysis showed no significant difference in the main mineral phases between the starting sample and the final residue, allowing for an alternative final destination of the residue
Summary
There is an imbalance between some metal supplies and world demand [1] due to the reduction of primary resources and high-grade ores [2, 3] For this reason, the interest in low-grade ores and mine tailings as metal sources has become significant over the years [4]. Mining activities generate large amounts of solid wastes that are usually stored long term under dam facilities [5]. These tailings can still contain valuable metals, such as copper, zinc, nickel, and gold, as well as hazardous elements, such as lead and arsenic [6]. There is an environmental risk associated with the liberation of toxic elements to the soil and groundwater, with the generation of acid mine drainage [7], and the disposal of waste on-site, such as dam failures [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: 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.
