Pressure leaching of chalcopyrite with oxalic acid and hydrogen peroxide

Turan, M. Deniz; Sarı, Z. Abidin; Nizamoğlu, Hasan

doi:10.1016/j.jtice.2020.10.021

Cited by 24 publications

(8 citation statements)

References 27 publications

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“…Levopimaric acid peroxide was produced extensively during oxidation, which introduced potential hazards to the production and storage processes [ 46 ]. In addition to causing potential heat damage, peroxide decomposition releases free radicals that form a wide range of byproducts [ 47 , 48 ]. Thermal parameters for Levopimaric acid peroxides are shown in Table 3 .…”

Section: Resultsmentioning

confidence: 99%

Thermal stability of levopimaric acid and its oxidation products

Li,

Chen,

Yan

et al. 2023

BMC Chemistry

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Biofuels are renewable alternatives to fossil fuels. Levopimaric acid‒base biofuels have attracted increasing attention. However, their stability remains a critical issue in practice. Thus, there is a strong impetus to evaluate the thermal stability of levopimaric acid. Through thermogravimetry (TG) and a custom-designed mini closed pressure vessel test (MCPVT) operating under isothermal and stepped temperature conditions, we investigated thermal oxidation characteristics of levopimaric acid under oxygen atmosphere. Thin-layer chromatography (TLC) and iodimetry were used to measure the hydrogen peroxides generated by levopimaric acid oxidation. A high pressure differential scanning calorimeter (HPDSC) was used to assess hydroperoxide thermal decomposition characteristics. Gas chromatography-mass spectrometry (GC-MS) was used to characterize the oxidation products. The thermal decomposition kinetics of levopimaric acid were thus elucidated, and a high peroxide value was detected in the levopimaric acid. The decomposition heat (QDSC) and exothermic onset temperature (Tonset) of hydroperoxides were 338.75 J g−1 and 375.37 K, respectively. Finally, levopimaric acid underwent a second-stage oxidation process at its melt point (423.15 K), resulting in complex oxidation products. Thermal oxidation of levopimaric acid could yield potential thermal hazards, indicating that antioxidants must be added during levopimaric acid application to protect against such hazardous effects.

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Section: Resultsmentioning

confidence: 99%

Thermal stability of levopimaric acid and its oxidation products

Li,

Chen,

Yan

et al. 2023

BMC Chemistry

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“…This oxide layer is removed using high-pressure water from the MS formed on the surface due to the high-temperature (1100–1300°C) and oxidizing environment during the production phase (Önkibar 2006 ; Gündoğdu 2013 ). Most of the MS is composed of iron oxide structures such as wustite (FeO), magnetite (Fe 3 O 4 ), and hematite (Fe 2 O 3 ) (Turan et al 2021 ). The scale typically contains around 70% Fe (El-Hussiny et al 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Green industry work: production of FeCl3 from iron and steel industry waste (mill scale) and its use in wastewater treatment

Solmaz,

Bölükbaşi,

Sari

2024

Environ Sci Pollut Res

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Mill scale (MS) is considered to be a significant metallurgical waste, but there is no economical method yet to utilize its metal content. In this study, which covers various processes in several stages, the solution of iron in MS, which is the Iron and Steel Industry (I&SI) waste, as FeCl3 (MS-FeCl3) in the thermoreactor in the presence of HCl, was investigated. In the next step, the conditions for using this solution as a coagulant in the treatment of I&SI wastewater were investigated using the jar test. The results of the treated water sample were compared by chemical oxygen demand (COD), total suspended solids (TSS), color, and turbidity analyses using commercial aluminum sulfate (Al2(SO4)3) and FeCl3 (C-FeCl3). Additionally, heavy metal analyses were conducted, and the treatment performance of three coagulants was presented. Accordingly, while 2.0 mg/L anionic polyelectrolyte was consumed at a dosage of 4.05 mg/L Al2(SO4)3 at pH 7.0, 0.25 mg/L anionic polyelectrolyte was consumed at a dosage of 1.29 mg/L at pH 5.0 in the C-FeCl3 and MS-FeCl3 studies. Also, Fe, Cr, Mn, Ni, Zn, Cd, Hg, and Pb removal efficiencies were over 93.56% for all three coagulant usage cases. The results showed that the wastewater treatment performance of MS-FeCl3 by the recycling of MS, which is an I&SI waste, was at the same level as C-FeCl3. Thus, thanks to recycling, waste scale can be used as an alternative to commercial products for green production. Graphical abstract

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“…Several methods have been used to increase reaction rates and break or avoid this passivation layer in leaching systems, including (i) leaching with powerful oxidizing agents such as O 3 [ 30 , 31 , 32 ], H 2 O 2 [ 6 , 33 , 34 , 35 ], potassium permanganate, and potassium dichromate [ 36 , 37 , 38 ], (ii) leaching with high pressure and temperature [ 34 , 39 , 40 , 41 ], and (iii) bacterial leaching [ 11 , 14 , 42 , 43 ], but these improvements are accompanied by limitations, mainly due to the high cost of oxidizers, the corrosive environments they provide and even low copper recoveries [ 39 , 44 ]. These kinds of considerations result in the hydrometallurgical route not being widely used in the dissolution of copper from primary sulfide ore, mainly because of slow leaching kinetics caused by the crystal structure of chalcopyrite (face-centered tetragonal lattice), which makes its lattice energy too high to break S-Cu-Fe bonds [ 23 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

Leaching of Copper Concentrate with Iodized Salts in a Saline Acid Medium: Part 1—Effect of Concentrations

Castellón

Taboada

2023

Materials

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One of the main problems in processing chalcopyrite ore with hydrometallurgical methods is its refractoriness, which is due to the formation of a layer that inhibits the contact of the ore with the leaching solution, thus reducing the dissolution rate. The main objective of this paper is to evaluate the leaching potential of iodide ions in copper extraction from chalcopyrite concentrate in an acidic seawater medium. Leaching tests were carried out in glass reactors stirred at 45 °C. Parameters such as iodide salt concentration and acidity were evaluated in ranges of 0–5000 ppm and 0–1.0 M, respectively. According to the results obtained, adding iodide ions to a medium acid enhances the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite. An increase in iodide ions improves the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite.

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Pressure leaching of chalcopyrite with oxalic acid and hydrogen peroxide

Cited by 24 publications

References 27 publications

Thermal stability of levopimaric acid and its oxidation products

Thermal stability of levopimaric acid and its oxidation products

Green industry work: production of FeCl3 from iron and steel industry waste (mill scale) and its use in wastewater treatment

Leaching of Copper Concentrate with Iodized Salts in a Saline Acid Medium: Part 1—Effect of Concentrations

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