Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching

Copper-bearing Waelz slag (CBWS) is a solid by-product of the Waelz process, the disposal of which faces significant environmental challenges. In this study, oxidative sulfuric acid leaching was applied for the recovery of valuable elements from a CBWS sample containing 26.23% Fe, 0.82% Cu, and 0.81...

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Main Authors: Pavel Grudinsky, Ekaterina Vasileva, Valery Dyubanov
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/3/330
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author Pavel Grudinsky
Ekaterina Vasileva
Valery Dyubanov
author_facet Pavel Grudinsky
Ekaterina Vasileva
Valery Dyubanov
author_sort Pavel Grudinsky
collection DOAJ
description Copper-bearing Waelz slag (CBWS) is a solid by-product of the Waelz process, the disposal of which faces significant environmental challenges. In this study, oxidative sulfuric acid leaching was applied for the recovery of valuable elements from a CBWS sample containing 26.23% Fe, 0.82% Cu, and 0.81% Zn. Experimental leaching was conducted at temperature ranges, durations, and solid-to-liquid (S/L) ratios of 25–90 °C, 5–240 min, and 0.05–0.5 g/cm<sup>3</sup>, respectively. The consumption rates of H<sub>2</sub>SO<sub>4</sub> and H<sub>2</sub>O<sub>2</sub> ranged within 9.18–15.29 mmol/g and 0–7.35 mmol/g, which, at a 1:4:1 g/cm<sup>3</sup>/cm<sup>3</sup> ratio, were equal to 225–375 g/dm<sup>3</sup> H<sub>2</sub>SO<sub>4</sub> and 0–250 g/dm<sup>3</sup> H<sub>2</sub>O<sub>2</sub>, respectively. Various oxidants such as H<sub>2</sub>O<sub>2</sub>, MnO<sub>2</sub>, air, oxygen, and Fe<sup>3+</sup> ions were tested in the leaching experiments. The optimal leaching conditions were proven to be a temperature of 70 °C, duration of 180 min, S/L ratio of 0.2 g/cm<sup>3</sup>, and consumption rate of 13.4 mmol H<sub>2</sub>SO<sub>4</sub>/g. These leaching conditions led to the recovery of 96.1% Fe, 87.0% Cu, and 86.9% Zn with the addition of 2.94 mmol H<sub>2</sub>O<sub>2</sub>/g and 95.2% Fe, 84.7% Cu, and 67.5% Zn with the addition of 0.095 g MnO<sub>2</sub>/g. These results suggest that metallic iron particles contained in a CBWS sample complicate copper dissolution.
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spelling doaj-art-d0824e5692eb4868a88c351e18e913fc2025-08-20T02:42:22ZengMDPI AGMetals2075-47012025-03-0115333010.3390/met15030330Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid LeachingPavel Grudinsky0Ekaterina Vasileva1Valery Dyubanov2I.P. Bardin Laboratory of Issues of Complex Ore Metallurgy, A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Science, 49 Leninsky Prosp., 119334 Moscow, RussiaI.P. Bardin Laboratory of Issues of Complex Ore Metallurgy, A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Science, 49 Leninsky Prosp., 119334 Moscow, RussiaI.P. Bardin Laboratory of Issues of Complex Ore Metallurgy, A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Science, 49 Leninsky Prosp., 119334 Moscow, RussiaCopper-bearing Waelz slag (CBWS) is a solid by-product of the Waelz process, the disposal of which faces significant environmental challenges. In this study, oxidative sulfuric acid leaching was applied for the recovery of valuable elements from a CBWS sample containing 26.23% Fe, 0.82% Cu, and 0.81% Zn. Experimental leaching was conducted at temperature ranges, durations, and solid-to-liquid (S/L) ratios of 25–90 °C, 5–240 min, and 0.05–0.5 g/cm<sup>3</sup>, respectively. The consumption rates of H<sub>2</sub>SO<sub>4</sub> and H<sub>2</sub>O<sub>2</sub> ranged within 9.18–15.29 mmol/g and 0–7.35 mmol/g, which, at a 1:4:1 g/cm<sup>3</sup>/cm<sup>3</sup> ratio, were equal to 225–375 g/dm<sup>3</sup> H<sub>2</sub>SO<sub>4</sub> and 0–250 g/dm<sup>3</sup> H<sub>2</sub>O<sub>2</sub>, respectively. Various oxidants such as H<sub>2</sub>O<sub>2</sub>, MnO<sub>2</sub>, air, oxygen, and Fe<sup>3+</sup> ions were tested in the leaching experiments. The optimal leaching conditions were proven to be a temperature of 70 °C, duration of 180 min, S/L ratio of 0.2 g/cm<sup>3</sup>, and consumption rate of 13.4 mmol H<sub>2</sub>SO<sub>4</sub>/g. These leaching conditions led to the recovery of 96.1% Fe, 87.0% Cu, and 86.9% Zn with the addition of 2.94 mmol H<sub>2</sub>O<sub>2</sub>/g and 95.2% Fe, 84.7% Cu, and 67.5% Zn with the addition of 0.095 g MnO<sub>2</sub>/g. These results suggest that metallic iron particles contained in a CBWS sample complicate copper dissolution.https://www.mdpi.com/2075-4701/15/3/330Waelz slagsulfuric acidleachingzinccopperiron
spellingShingle Pavel Grudinsky
Ekaterina Vasileva
Valery Dyubanov
Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
Metals
Waelz slag
sulfuric acid
leaching
zinc
copper
iron
title Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
title_full Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
title_fullStr Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
title_full_unstemmed Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
title_short Recycling Potential of Copper-Bearing Waelz Slag via Oxidative Sulfuric Acid Leaching
title_sort recycling potential of copper bearing waelz slag via oxidative sulfuric acid leaching
topic Waelz slag
sulfuric acid
leaching
zinc
copper
iron
url https://www.mdpi.com/2075-4701/15/3/330
work_keys_str_mv AT pavelgrudinsky recyclingpotentialofcopperbearingwaelzslagviaoxidativesulfuricacidleaching
AT ekaterinavasileva recyclingpotentialofcopperbearingwaelzslagviaoxidativesulfuricacidleaching
AT valerydyubanov recyclingpotentialofcopperbearingwaelzslagviaoxidativesulfuricacidleaching