The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores: VIII. Field of thermal stability of synthetic analog of chalcomenite, its dehydration and dissociation

Фокина, Е. Л.; Klimova, E. V.; Charykova, M. V.; Кривовичев, В. Г.; Platonova, N. V.; Semenova, V. V.; Depmeier, Wulf

doi:10.1134/s1075701514070058

Cited by 12 publications

(8 citation statements)

References 7 publications

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“…At 505 °C (Figure 6), [Cu 2 O(SeO 3 )] is still a main crystallized phase, but a new phase, tenorite (CuO) is also identified and becomes the predominant phase at 600 °C. Based on the %ML of Figure 4, on the results of XRD diffraction and data from the research work performed by Fokina et al [36], the two steps of Cu 4 O(SeO 3 ) 3 conversion into CuO and SeO 2 as final products can be described by Equations (2) and (3). Diffractograms of products obtained at 685 °C and 770 °C confirm the presence of well-crystallized phases of silver (gold), tenorite and quartz, which was present in all analyzed residues.…”

Section: Resultsmentioning

confidence: 99%

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere

et al. 2019

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Development of our modern society requests a number of critical and strategic elements (platinum group metals, In, Ga, Ge…) and high value added elements (Au, Ag, Se, Te, Ni…) which are often concentrated in by-products during the extraction of base metals (Cu, Pb, Zn…). Further, recycling of end-of-life materials employed in high technology, renewable energy and transport by conventional extractive processes also leads to the concentration of such chemical elements and their compounds in metallurgical by-products and/or co-products. One of these materials, copper anode slime (CAS), derived from a copper electrolytic refining factory, was used for this study. The sample was subjected to isothermal treatment from 225 to 770 °C under air atmosphere and the reaction products were systematically analyzed by scanning electron microscopy through energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behavior of the treated sample. The main components of the anode slime (CuAgSe, Cu2-xSeyS1-y, Ag3AuSe2) react with oxygen, producing mostly copper and selenium oxides as well as Ag-Au alloys as final products at temperatures higher than 500 °C. Selenium dioxide (SeO2) is volatilized and recovered in pure state by cooling the gaseous phase, whilst copper(II) oxide, silver, gold and tellurium remain in the treatment residue.

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Section: Resultsmentioning

confidence: 99%

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere

et al. 2019

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“…Chalcomenite is the more abundant mineral; clinochalcomenite is poorly documented and remains a controversial mineral species. The thermal stability, the solubility and thermochemical calorimetric investigations were carried out on a synthetic analogue of chalcomenite [17,54,55].…”

Section: Thermodynamic System Cu-se-h2omentioning

confidence: 99%

The Thermodynamics of Selenium Minerals in Near-Surface Environments

2017

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Selenium compounds are relatively rare as minerals; there are presently only 118 known mineral species. This work is intended to codify and systematize the data of mineral systems and the thermodynamics of selenium minerals, which are unstable (selenides) or formed in near-surface environments (selenites), where the behavior of selenium is controlled by variations of the redox potential and the acidity of solutions at low temperatures and pressures. These parameters determine the migration of selenium and its precipitation as various solid phases. All selenium minerals are divided into four groups-native selenium, oxide, selenides, and oxysalts-anhydrous selenites (I) and hydrous selenites and selenates (II). Within each of the groups, minerals are codified according to the minimum number of independent elements necessary to define the composition of the mineral system. Eh-pH diagrams were calculated and plotted using the Geochemist's Workbench (GMB 9.0) software package. The Eh-pH diagrams of the Me-Se-H 2 O systems (where Me = Co, Ni, Fe, Cu, Pb, Zn, Cd, Hg, Ag, Bi, As, Sb, Al and Ca) were plotted for the average contents of these elements in acidic waters in the oxidation zones of sulfide deposits. The possibility of the formation of Zn, Cd, Ag and Hg selenites under natural oxidation conditions in near surface environments is discussed.

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“…At 505 °C [Cu 2 O(SeO 3 )] is still the main crystallized phase, but tenorite (CuO) is also identified and becomes the main phase at higher temperature. According to the data reported in Part I [ 1 ] and those given by Fokina et al [ 43 ], the two steps of Cu 4 O(SeO 3 ) 3 conversion into CuO and SeO 2 as final products can be described by Equations (4) and (5): Cu 4 O(SeO 3 ) 3 → 2Cu 2 O(SeO 3 ) + SeO 2 2Cu 2 O(SeO 3 ) → 4CuO + 2SeO 2 …”

Section: Resultsmentioning

confidence: 98%

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High-Value Elements from By-Products and End-of-Life Materials, Part II: Processing in Presence of Halogenated Atmosphere

et al. 2020

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During the treatment of copper anode slime (CAS) under an air atmosphere, several aspects of the interactions of its main components (CuAgSe, Cu2−xSeyS1−y, Ag3AuSe2) with oxygen were described in Part I. As a comparative and complementary study, this work deals with the thermal behavior of CAS under air in the presence of polyvinyl chloride (PVC) between 195 and 770 °C. The preliminary thermal treatment of an e-waste sample containing brominated substances was also performed. The reaction products were systematically analyzed by scanning electron microscopy through energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) to investigate the thermal behaviors of the studied samples in a halogenated medium. At low temperatures, the copper, silver and selenium compounds of the CAS reacted with the HCl, issued from PVC degradation, leading to the formation of their respective chlorides. Bromides of valuable metals (Cu, Pb, Sn…) were synthesized during the e-waste treatment at 500 °C and they were distributed between the solid residue and gaseous phase. The data obtained give an insight into the reactivity of several metals towards halogenated substances, which may be valuable information for conducting the extraction and recycling of targeted elements from industrial by-products and end-of-life materials by a thermochemical route.

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The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores: VIII. Field of thermal stability of synthetic analog of chalcomenite, its dehydration and dissociation

Cited by 12 publications

References 7 publications

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High Value Elements from By-Products and End-of-Life Materials, Part I: Treatment of a Copper By-Product in Air Atmosphere

The Thermodynamics of Selenium Minerals in Near-Surface Environments

Thermochemical Route for Extraction and Recycling of Critical, Strategic and High-Value Elements from By-Products and End-of-Life Materials, Part II: Processing in Presence of Halogenated Atmosphere

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