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Sany, Seyed Mohammad KhoshkhooORCID iD iconorcid.org/0000-0002-3255-3051
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Publications (10 of 11) Show all publications
Khoshkhoo, M., Dopson, M., Engström, F. & Sandström, Å. (2017). New insights into the influence of redox potential on chalcopyrite leaching behaviour. Minerals Engineering, 100, 9-16
Open this publication in new window or tab >>New insights into the influence of redox potential on chalcopyrite leaching behaviour
2017 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 100, p. 9-16Article in journal (Refereed) Published
Abstract [en]

Chalcopyrite (CuFeS2) is the most economically important and most refractory copper mineral when treated in conventional sulphate media leaching systems. In this study, the effect of solution redox potential on leaching of a pure and a pyritic chalcopyrite concentrate was investigated using concentrates with fresh and aged surfaces. In experiments using concentrates with fresh surfaces, the response to redox potential depended on the presence of pyrite: fresh pyritic concentrate leached more effectively at low redox potential (in agreement with reductive leaching mechanisms), while the leaching efficiencies from fresh pure concentrate were similar at high and low redox potentials. The data suggested that the reductive leaching mechanism does not necessarily result in higher and faster recoveries in the absence of the galvanic interaction induced by the presence of pyrite. It was also found that exposure of chalcopyrite to atmospheric oxidation prior to leaching (ageing) had an effect on leaching behaviour in response to redox potential: copper recoveries in leaching of aged concentrates were higher at high redox potentials. This behaviour was attributed to the presence of iron–oxyhydroxides on the surface of aged concentrates. Based on the data from this investigation and previous surface studies, it is proposed that iron–oxyhydroxides play an important role in triggering the hindered dissolution of chalcopyrite.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-59595 (URN)10.1016/j.mineng.2016.10.003 (DOI)000390508900002 ()2-s2.0-84991660408 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-10-10 (andbra)

Available from: 2016-10-10 Created: 2016-10-10 Last updated: 2018-09-13Bibliographically approved
Johansson, Ö., Pamidi, T., Khoshkhoo, M. & Sandström, Å. (2017). Sustainable and energy efficient leaching of tungsten(W) by ultrasound controlled cavitation. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Sustainable and energy efficient leaching of tungsten(W) by ultrasound controlled cavitation
2017 (English)Report (Other academic)
Abstract [en]

The project aims to use ultrasound controlled cavitation to achieve a more energy efficient leaching process. Locally, collapsing cavitation bubbles cause an extremely high pressure, shock waves and high temperature, which provide an opportunity to perform the leaching process at a much lower temperature than in an autoclave (20 bar overpressure and 220 ° C). The results show that the method works, but that a higher static pressure and thus temperatures are necessary to achieve a leaching recovery rate corresponding to today's autoclave technology. Another process parameter of importance is flow control and the initiation of cavitation bubbles that occur through a geometrically optimized nozzle (orifice plate). Numerical and experimental adaptation of the developed reactor with respect to the leaching conditions (Sodium hydroxide and Scheelite concentrate), required more time than expected. Best test results show that an energy supplement with ultrasonic controlled cavitation of 104 kWh / kg increases the leaching recovery by 21%. The leaching reagent temperature 60° C was determined regarding available reference data and was thought to be close to optimum for intensive cavitation in atmospheric pressure. Optimum temperature relates to the leaching reagent, vaporization temperature, density, boiling point, surface tension, and viscosity. Generally, for leaching is that higher temperatures are required to increase the chemical reaction rate (requires overpressure). The modified reactor principle provides stable results and is possible to scale up. Higher cavitation intensity for shorter finishing time and higher recovery rate require advanced flow induction, multiple excitation frequencies adapted to the optimized reactor geometry, as well as optimal process pressure and temperature.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2017. p. 20
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Ultrasound, Cavitation, Leaching, Scheelite, Vibro acoustic optimization
National Category
Mineral and Mine Engineering Fluid Mechanics and Acoustics Metallurgy and Metallic Materials
Research subject
Engineering Acoustics; Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-66286 (URN)978-91-7790-160-0 (ISBN)
Projects
Vinnova SIP-Strim
Funder
Vinnova, 2016-02620Vinnova
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2019-09-11Bibliographically approved
Sany, S. M. (2016). Chalcopyrite (Bio)leaching in Sulphate Solutions: An Investigation into Hindered Dissolution with a Focus on Solution Redox Potential (ed.). (Doctoral dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Chalcopyrite (Bio)leaching in Sulphate Solutions: An Investigation into Hindered Dissolution with a Focus on Solution Redox Potential
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Chalcopyrite (CuFeS2) is the most abundant and the most economically important copper mineral. Increasing worldwide demand for copper accompanied by exhaustion of copper resources necessitate the development of new processes for treating lower-grade copper ores. Heap (bio)leaching of copper oxides and secondary sulphides (covellite (CuS) and chalcocite (Cu2S)) is a proven technology and a convenient process nowadays. However, chalcopyrite is recalcitrant to leaching and bioleaching in conventional leaching systems in sulphate media. Slow dissolution of chalcopyrite is attributed to the formation of compounds on the surface of the mineral during its dissolution and is often termed “passivation” or “hindered dissolution”. There is still no consensus about the nature of the passivation layer. There are, however, four proposed candidates suggested in the literature: metal deficient sulphides, polysulphides, jarosite and elemental sulphur. This project was aimed to further investigate the chalcopyrite dissolution and its passivation under strictly controlled redox potential conditions. The leaching experiments of the aged and fresh chalcopyrite concentrate under identical conditions showed that copper dissolution was significantly lower from the aged concentrate. The common understanding of reductive leaching mechanism (i.e. higher recoveries at lower redox potentials) was not valid for aged concentrates. Aged concentrates gave steadily increasing recoveries with increased redox potential. The hindering effect exerted from the atmospheric oxidation products on the surface of the aged concentrates was found to be responsible for this behaviour. It was also shown that the reductive leaching mechanism would be beneficial in the presence of an active galvanic interaction. Experiments using a pyritic concentrate resulted in higher recoveries at low redox potential while the dissolution rates were similar at low and high redox potentials using a relatively pure concentrate. In addition, the effect of initial copper concentration had no influential effect on the leaching rates for possible industrial processes. Redox potential development during moderately thermophilic bioleaching experiments of a pyritic chalcopyrite concentrate and a relatively pure chalcopyrite concentrate were chemically/electrochemically mimicked in the absence of microorganisms. The copper recoveries in absence and presence of microorganisms were similar. In some of the abiotic experiments, jarosite precipitated due to a loss of control of the redox potential. However, presence of bulk jarosite did not hamper the copper recovery compared to the bioleaching experiments where there was no bulk jarosite formation. Bio-oxidation of elemental sulphur did not have a positive effect on the leaching behaviour compared to the abiotic experiments where bulk elemental sulphur accumulated. Isotopic fractionations of copper and iron during the bioleaching and abiotic experiments showed that regardless of presence or absence of microorganisms the copper and iron isotopes fractionation followed a similar trend and that such analyses could be used in natural systems as an indicator of the oxidation extent. Surface analyses using X-ray photoelectron spectroscopy (XPS) measurements revealed that common phases on the surface of the samples leached for different durations were iron-oxyhydroxides and elemental sulphur. The elemental sulphur on the surface of the samples was bound to the surface rigidly in a way that it did not sublimate in the ultra-high vacuum environment of the XPS spectrometer at room temperature measurements. Surface jarosite was observed in only one sample but no correlation between its presence and the hindered leaching could be made. It is proposed that iron-oxyhydroxides are the main precursor of chalcopyrite hindered dissolution in sulphate media where their inevitable formation entraps surface elemental sulphur resulting in a consolidated phase on the surface. It was shown that when suitable conditions are met, high copper recoveries can be obtained before the surface is finally hindered.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2016
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-18750 (URN)a25ec64d-437c-45ed-ab50-8de2df31cc5b (Local ID)978-91-7583-507-5 (ISBN)978-91-7583-508-2 (ISBN)a25ec64d-437c-45ed-ab50-8de2df31cc5b (Archive number)a25ec64d-437c-45ed-ab50-8de2df31cc5b (OAI)
Note
Godkänd; 2016; 20151215 (seykos); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Mohammad Khoshkhoo Ämne: Processmetallurgi /Process Metallurgy Avhandling: Chalcopyrite (Bio)leachning in Sulphate Solutions An Investigation into Hindered Dissolution with a Focus on Solution Redox Potential Opponent: Professor Joachim Petersen, Department of Chemical Engineering, University of Cape Town, Rondebosch, Sydafrika. Ordförande: Professor Åke Sandström, Avd för mineralteknik och metallurgi, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet, Luleå. Tid: Fredag 26 februari, 2016 kl 09.30 Plats: E632, Luleå tekniska universitetAvailable from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Rodríguez, N. P., Khoshkhoo, M., Sandström, Å., Rodushkin, I., Alakangas, L. & Öhlander, B. (2015). Isotopic signature of Cu and Fe during bioleaching and electrochemical leaching of a chalcopyrite concentrate (ed.). Paper presented at . International Journal of Mineral Processing, 134, 58-65
Open this publication in new window or tab >>Isotopic signature of Cu and Fe during bioleaching and electrochemical leaching of a chalcopyrite concentrate
Show others...
2015 (English)In: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 134, p. 58-65Article in journal (Refereed) Published
Abstract [en]

Bioleaching is an important process in metallurgy and in environmental sciences, either for the acquisition of metals or for the formation of acid rock drainage. In this study the implications of the processes during bioleaching of a pyritic chalcopyrite concentrate were analysed regarding its Cu and Fe isotope fractionation. The development of the redox potential during the bioleaching experiment was then simulated in an electrochemical cell in absence of microorganisms to investigate the effect of microbial activity on the Cu and Fe isotope fractionations. The leaching experiments were performed for 28 days at 45 °C with a solid content of 2.5% (w/v) at pH 1.5. It was found that Cu dissolution efficiency was similar in both experiments and the leaching curves were linear with no sign of passivation due to presence of pyrite. The heavy Cu isotope (δ65Cu) was leached more easily and as a result the leachate was enriched with the heavy Cu isotope at the beginning of both experiments and as the leaching progressed δ65Cu values in the leachate became similar to the ones of the chalcopyrite concentrate, confirming an equilibrium fractionation happening in a closed system. There was no distinct difference in the Cu and Fe isotope fractionations in absence and presence of microorganisms. Finally based on Cu and Fe isotope signatures, a simplified method is suggested for the estimation of the leaching extent during the oxidisation of sulphide materials in natural systems.

National Category
Metallurgy and Metallic Materials Geochemistry
Research subject
Process Metallurgy; Applied Geology
Identifiers
urn:nbn:se:ltu:diva-5240 (URN)10.1016/j.minpro.2014.11.010 (DOI)000348960600008 ()2-s2.0-84924082946 (Scopus ID)348dc9fd-2b99-4601-aa07-7e40c905974c (Local ID)348dc9fd-2b99-4601-aa07-7e40c905974c (Archive number)348dc9fd-2b99-4601-aa07-7e40c905974c (OAI)
Note
Validerad; 2014; Nivå 2; 20141128 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2019-11-22Bibliographically approved
Sany, S. M., Dopson, M. & Sandström, Å. (2015). Role of Microbial Activity in Bioleaching of a Pyritic and a Pure Chalcopyrite Concentrate (ed.). Paper presented at International Biohydrometallurgy Symposium : 05/10/2015 - 09/10/2015. Advanced Materials Research, 1130, 209-213
Open this publication in new window or tab >>Role of Microbial Activity in Bioleaching of a Pyritic and a Pure Chalcopyrite Concentrate
2015 (English)In: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 1130, p. 209-213Article in journal (Refereed) Published
Abstract [en]

Leaching of a pyritic and a pure chalcopyrite concentrate was carried out in stirred tank reactors in the absence and presence of a mixed culture of moderately thermophilic microorganisms at 45°C and pH 1.5. To study the effect of microbial activity on copper dissolution, the abiotic experiments were performed under accurately controlled redox potential conditions to reproduce the same oxidising conditions recorded during the bioleaching experiments. X-ray photoelectron spectrometry (XPS) was used to study the surface of chalcopyrite chips leached for different durations. The results showed that the microorganisms in cases of both concentrates did not have any effect in the copper leaching efficiency other than oxidation of ferrous to ferric ions. Biooxidation of elemental sulphur did not improve the leaching efficiency and bulk and surface jarosite had no negative effect on dissolution. A composite layer composed of mainly elemental sulphur and iron-oxy-hydroxide was found to be responsible for the hindered dissolution.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-29876 (URN)10.4028/www.scientific.net/AMR.1130.209 (DOI)37e3ac66-a9ed-4a31-b501-c3c853fdca62 (Local ID)37e3ac66-a9ed-4a31-b501-c3c853fdca62 (Archive number)37e3ac66-a9ed-4a31-b501-c3c853fdca62 (OAI)
Conference
International Biohydrometallurgy Symposium : 05/10/2015 - 09/10/2015
Note
Validerad; 2016; Nivå 1; 20151029 (seykos); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-30Bibliographically approved
Khoshkhoo, M. (2014). An investigation on the role of microorganisms on chalcopyrite leaching efficiency (ed.). Paper presented at Conference in Minerals Engineering 2014 : 04/02/2014 - 05/02/2014. Paper presented at Conference in Minerals Engineering 2014 : 04/02/2014 - 05/02/2014.
Open this publication in new window or tab >>An investigation on the role of microorganisms on chalcopyrite leaching efficiency
2014 (English)Conference paper, Oral presentation only (Refereed)
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-30025 (URN)3b3055f9-47e8-4e63-b08f-960eda25289b (Local ID)3b3055f9-47e8-4e63-b08f-960eda25289b (Archive number)3b3055f9-47e8-4e63-b08f-960eda25289b (OAI)
Conference
Conference in Minerals Engineering 2014 : 04/02/2014 - 05/02/2014
Note
Godkänd; 2014; 20140515 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Khoshkhoo, M. (2014). Chalcopyrite Dissolution in Sulphate-Based Leaching and Bioleaching Systems (ed.). (Licentiate dissertation). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>Chalcopyrite Dissolution in Sulphate-Based Leaching and Bioleaching Systems
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Chalcopyrite (CuFeS2) is the most abundant and the most economically important copper mineral. Increasing worldwide demand for copper accompanied by exhaustion of copper resources necessitate the development of new processes for treating lower-grade copper ores. Heap (bio)leaching of copper oxides and secondary sulphides (covellite (CuS) and chalcocite (Cu2S)) is a proven technology and a convenient process due to its simplicity and relatively low capital investment requirement. As a result, the technology appears to be an attractive process option for treatment of low-grade chalcopyrite ores as well. However, chalcopyrite is recalcitrant to leaching and bioleaching in conventional heaps: its dissolution is slow and it halts on a low level of copper extraction usually unacceptable for a commercial practice. Slow dissolution of chalcopyrite is attributed to the formation of compounds on the surface of the mineral during its oxidative dissolution, often termed “passivation”. There is still no consensus about the nature of the passivation layer. There are, however, four proposed candidates suggested in the literature: metal deficient sulphides, polysulphides, jarosite and elemental sulphur. This project was aimed to further investigate the chalcopyrite dissolution and its passivation.In this thesis, dissolution of a pyritic and a pure chalcopyrite concentrate was studied in stirred tank reactors in the absence and presence of moderately thermophilic microorganisms. The abiotic experiments were performed under accurately controlled redox potential conditions to reproduce the same oxidising conditions recorded during the bioleaching experiments. The results showed that the microorganisms did not have any effect in the copper leaching efficiency other than oxidation of ferrous ions to ferric ions. Comparing the copper dissolution rates in the experiments where bulk elemental sulphur was formed with those experiments where the elemental sulphur was oxidised to sulphate due to microbial activity showed that the bulk elemental sulphur did not hinder the dissolution. The same phenomenon was observed in case of bulk jarosite. Under otherwise identical leaching conditions, the presence of bulk jarosite did not decrease the leaching efficiency compared to those experiments were bulk jarosite was not formed. It was also shown that surface spectroscopic methodologies such as X-ray photoelectron spectroscopy (XPS) cannot be applied on powder leached samples due to interfering data from the bulk precipitated species. As a result, massive natural chalcopyrite samples were II prepared and used in the leaching experiments for XPS measurements. Different samples in different stages of leaching were extracted from the biotic and abiotic experiments and analysed by XPS. Results indicated that the surface elemental sulphur was not oxidised by bacterial activity. The data revealed that the common phases on the surface of the samples leached biotically and abiotically for different durations were elemental sulphur and iron-(oxy)hydroxides. The surface elemental sulphur was rigidly bound to the surface and did not volatise in the room temperature XPS measurements. Jarosite was observed in only one sample from the abiotic experiment, but no correlation between its presence and the slow dissolution could be made. Other minor surface compounds such as iron-sulphate was also observed in some samples with no contribution to the leaching behaviour. It was concluded that a multi-component surface phase consisting of mainly sulphur and iron-hydroxides were responsible for the slow chalcopyrite dissolution.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2014
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-17698 (URN)4b9181d2-e38e-446e-9ef4-d355caad9739 (Local ID)978-91-7439-921-9 (ISBN)978-91-7439-922-6 (ISBN)4b9181d2-e38e-446e-9ef4-d355caad9739 (Archive number)4b9181d2-e38e-446e-9ef4-d355caad9739 (OAI)
Note

Godkänd; 2014; 20140410 (seykos); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Mohammad Khoshkhoo Ämne: Processmetallurgi/Process Metallurgy Uppsats: Chalcopyrite Dissolution in Sulphate-Based Leaching and Bioleaching Systems Examinator: Professor Åke Sandström, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Professor Wolfgang Sand, Fakultät für Chemie – Biofilm Centre, Universität Duisburg-Essen, Tyskland Tid: Måndag den 16 juni 2014 kl 09.30 Plats: E632, Luleå tekniska universitet

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Khoshkhoo, M., Dopson, M., Shchukarev, A. & Sandström, Å. (2014). Chalcopyrite leaching and bioleaching: An X-ray photoelectron spectroscopic (XPS) investigation on the nature of hindered dissolution (ed.). Paper presented at . Hydrometallurgy, 149, 220-227
Open this publication in new window or tab >>Chalcopyrite leaching and bioleaching: An X-ray photoelectron spectroscopic (XPS) investigation on the nature of hindered dissolution
2014 (English)In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 149, p. 220-227Article in journal (Refereed) Published
Abstract [en]

Chalcopyrite (CuFeS2) is both the most economically important and the most difficult copper mineral to (bio)leach. The main reason for the slow rate of chalcopyrite dissolution is the formation of a layer on the surface of the mineral that hinders dissolution, termed “passivation”. The nature of this layer is still under debate. In this work, the role of bacterial activity was examined on the leaching efficiency of chalcopyrite by mimicking the redox potential conditions during moderately thermophilic bioleaching of a pure chalcopyrite concentrate in an abiotic experiment using chemical/electrochemical methods. The results showed that the copper recoveries were equal in the presence and absence of the mixed culture. It was found that the presence of bulk jarosite and elemental sulphur in the abiotic experiment did not hamper the copper dissolution compared to the bioleaching experiment. The leaching curves had no sign of passivation, rather that they indicated a hindered dissolution. XPS measurements carried out on massive chalcopyrite samples leached in the bioleaching and abiotic experiments revealed that common phases on the surface of the samples leached for different durations of time were elemental sulphur and iron-oxyhydroxides. The elemental sulphur on the surface of the samples was rigidly bound in a way that it did not sublimate in the ultra-high vacuum environment of the XPS spectrometer at room temperature. Jarosite was observed in only one sample from the abiotic experiment but no correlation between its presence and the hindered leaching behaviour could be made. In conclusion, a multi-component surface layer consisting of mainly elemental sulphur and iron-oxyhydroxides were considered to be responsible for the hindered dissolution.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-8464 (URN)10.1016/j.hydromet.2014.08.012 (DOI)000344204400026 ()2-s2.0-84907266299 (Scopus ID)6fa0719d-cd2a-4a50-a13c-5af5467c1611 (Local ID)6fa0719d-cd2a-4a50-a13c-5af5467c1611 (Archive number)6fa0719d-cd2a-4a50-a13c-5af5467c1611 (OAI)
Note
Validerad; 2014; 20140904 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Khoshkhoo, M., Dopson, M., Shchukarev, A. & Sandström, Å. (2014). Electrochemical Simulation of Redox Potential Development in Bioleaching of a Pyritic Chalcopyrite Concentrate (ed.). Paper presented at . Hydrometallurgy, 144-145, 7-14
Open this publication in new window or tab >>Electrochemical Simulation of Redox Potential Development in Bioleaching of a Pyritic Chalcopyrite Concentrate
2014 (English)In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 144-145, p. 7-14Article in journal (Refereed) Published
Abstract [en]

The majority of the world’s copper reserves are bound in the sulphide mineral chalcopyrite (CuFeS2), but supply of the copper is hindered by the recalcitrance of chalcopyrite to (bio)leaching. The main reason for the slow rate of chalcopyrite dissolution is the formation of a layer on the surface of the mineral that hinders dissolution, termed “passivation”. The nature of this layer and the role of microorganisms in chalcopyrite leaching behaviour are still under debate. Moderately thermophilic bioleaching of a pyritic chalcopyrite concentrate was mimicked in an electrochemical vessel to investigate the effect of absence and presence of microorganisms in copper dissolution efficiency. Data from the redox potential development during bioleaching was used to program a redox potential controller in an electrochemical vessel to accurately reproduce the same leaching conditions in the absence of microorganisms. Two electrochemical experiments were carried out with slightly different methods of redox potential control. Despite massive precipitation of iron as jarosite in one of the electrochemically controlled experiments and formation of elemental sulphur in both electrochemical experiments, the efficiencies of copper dissolution were similar in the electrochemical tests as well as in the bioleaching experiment. No passivation was observed and copper recoveries exhibited a linear behaviour versus the leaching time possibly due to the galvanic effect between chalcopyrite and pyrite. The data suggest that the main role of microorganisms in bioleaching of a pyritic chalcopyrite concentrate was regeneration of ferric iron. It was also shown that the X-Ray photoelectron spectroscopy (XPS) measurements on the residues containing bulk precipitates cannot be employed for a successful surface characterization.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-10457 (URN)10.1016/j.hydromet.2013.12.003 (DOI)000335614000002 ()2-s2.0-84893828943 (Scopus ID)943fad9a-e4d3-4220-b3d0-e3e5f36dde77 (Local ID)943fad9a-e4d3-4220-b3d0-e3e5f36dde77 (Archive number)943fad9a-e4d3-4220-b3d0-e3e5f36dde77 (OAI)
Note
Validerad; 2014; 20140128 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Khoshkhoo, M., Dopson, M. & Sandström, Å. (2013). Bioleaching and electrochemical leaching of a pyritic chalcopyrite concentrate (ed.). Paper presented at International Biohydrometallurgy Symposium : 08/10/2013 - 11/10/2013. Advanced Materials Research, 825, 254-257
Open this publication in new window or tab >>Bioleaching and electrochemical leaching of a pyritic chalcopyrite concentrate
2013 (English)In: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 825, p. 254-257Article in journal (Refereed) Published
Abstract [en]

Moderately thermophilic bioleaching of a pyritic chalcopyrite concentrate was mimicked in an electrochemical vessel. The bioleaching was carried out for 28 days at 45°C with 2.5% (wt/vol) solid content at pH 1.5. Data from the redox potential development was used to program a redox potential controller in an electrochemical vessel to reproduce the same leaching conditions in the absence of microorganisms. Despite precipitation of iron as jarosite and formation of elemental sulphur in the electrochemical experiment, the copper recoveries were almost the same in both experiments.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-28013 (URN)10.4028/www.scientific.net/AMR.825.254 (DOI)000336185400060 ()2-s2.0-84886780282 (Scopus ID)1a7e32de-2ed1-4b54-ac61-64fb3dbc7be0 (Local ID)1a7e32de-2ed1-4b54-ac61-64fb3dbc7be0 (Archive number)1a7e32de-2ed1-4b54-ac61-64fb3dbc7be0 (OAI)
Conference
International Biohydrometallurgy Symposium : 08/10/2013 - 11/10/2013
Note

Validerad; 2013; 20131004 (aksa); Konferensartikel i tidskrift

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2019-04-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3255-3051

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