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Sundqvist Ökvist, LenaORCID iD iconorcid.org/0000-0003-3363-351X
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Publications (10 of 31) Show all publications
Shakibania, S., Sundqvist-Öqvist, L., Rosenkranz, J. & Ghorbani, Y. (2024). Application of Anti-Solvent Crystallization for High-Purity Potash Production from K-Feldspar Leaching Solution. Processes, 12(7), Article ID 1385.
Open this publication in new window or tab >>Application of Anti-Solvent Crystallization for High-Purity Potash Production from K-Feldspar Leaching Solution
2024 (English)In: Processes, ISSN 2227-9717, Vol. 12, no 7, article id 1385Article in journal (Refereed) Published
Abstract [en]

Potassium-containing feldspars provide a high potential for producing potash, a product with widespread use in agriculture. The present work assesses applying the anti-solvent crystallization method for the purification and recovery of high-purity muriate of potash (KCl) from feldspar leaching solutions. Initially, screening experiments were carried out on a synthetic leaching solution with the aim of analyzing the crystallization behavior of key components. Screening experiments were performed using five anti-solvents, namely methanol, ethanol, acetone, 2-propanol, and ethylene glycol. Acetone and 2-propanol were viable options for crystallization of potassium chloride. Then, the effects of anti-solvent ratio (O/A), time, and anti-solvent addition rate on potassium-chloride crystallization were further investigated using acetone and 2-propanol. A recovery of 83% of potassium was achieved when using acetone at the O/A of 5 with the addition rate of 10 mL/min, at room temperature with a hold time of 180 min. The optimum conditions for 2-propanol were determined to be similar, except for using a 5 mL/min addition rate for 79% recovery. The final muriate of potash products had a purity of over 99.9% using either of the anti-solvent. However, differences in morphology and crystal size of products were observed. Acetone-formed potash crystals were aggregates of cubic crystals with an average size of 3 microns, while 2-propanol-formed potash crystals were 20 microns in size as cubic particles with a hollow core. Despite having almost the same performance in potassium recovery, acetone was found to be a more feasible anti-solvent for potash recovery due to simpler downstream solvent recovery.

Place, publisher, year, edition, pages
Multidisciplinary Digital Publishing Institute (MDPI), 2024
Keywords
2-propanol, acetone, anti-solvent crystallization, K-feldspar, muriate, potash
National Category
Chemical Engineering Industrial Biotechnology
Research subject
Mineral Processing; Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-108494 (URN)10.3390/pr12071385 (DOI)001277011600001 ()2-s2.0-85199906454 (Scopus ID)
Funder
Vinnova, 2022-00023
Note

Validerad;2024;Nivå 2;2024-08-08 (hanlid);

Full text license: CC BY

Available from: 2024-08-08 Created: 2024-08-08 Last updated: 2024-10-17Bibliographically approved
Sundqvist Ökvist, L., Lundgren, M., From, L.-E., Eck, J., Kjellberg, M. & Ahmed, H. (2024). Realization of Bio-Coal Injection into the Blast Furnace. Metals, 14(9), Article ID 969.
Open this publication in new window or tab >>Realization of Bio-Coal Injection into the Blast Furnace
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2024 (English)In: Metals, ISSN 2075-4701, Vol. 14, no 9, article id 969Article in journal (Refereed) Published
Abstract [en]

The steel industry accounts, according to the International Energy Agency, for ~6.7% of global CO2 emissions, and the major portion of its contribution is from steelmaking via the blast furnace (BF) route. In the short term, a significant reduction in fossil CO2 emissions can be achieved through the introduction of bio-coal into the BF as part of cold bonded briquettes, by injection, or as part of coke. The use of bio-coal-containing residue briquettes was previously demonstrated in industrial trials in Sweden, whereas bio-coal injection was only tested on a pilot scale or in one-tuyere tests. Therefore, industrial trials replacing part of the pulverized coal (PC) were conducted. It was concluded that the grinding, conveying, and injection of up to 10% of charcoal (CC) with PC can be safely achieved without negative impacts on PC injection plant or BF operational conditions and without losses of CC with the dust. From a process point of view, higher addition is possible, but it must be verified that grinding and conveying is feasible. Through an experimentally validated computational fluid flow model, it was shown that a high moisture content and the presence of oversized particles delay devolatilization and ignition, lowering the combustion efficiency. By using CC with similar heating value to PC, compositional variations in the injected blend are not critical.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
bio-coal, charcoal, reducing agent, injection, CO2 emission
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-110273 (URN)10.3390/met14090969 (DOI)001326312800001 ()2-s2.0-85205082989 (Scopus ID)
Funder
Swedish Energy Agency, P44676-1
Note

Validerad;2024;Nivå 2;2024-10-07 (sarsun);

Full text license: CC BY 4.0;

Available from: 2024-10-07 Created: 2024-10-07 Last updated: 2024-12-02Bibliographically approved
Hellgren, S., Engström, F. & Sundqvist Ökvist, L. (2024). The Characterization of Residues Related to the Roasting– Leaching–Electrowinning Zinc Production Route for Further Metal Extraction. Metals, 14(1), Article ID 73.
Open this publication in new window or tab >>The Characterization of Residues Related to the Roasting– Leaching–Electrowinning Zinc Production Route for Further Metal Extraction
2024 (English)In: Metals, ISSN 2075-4701, Vol. 14, no 1, article id 73Article in journal (Refereed) Published
Abstract [en]

Super-hot acid leach residue is generated during zinc production in the roasting–leaching–electrowinning route, where both primary and secondary resources are used as feed material. This residue may contain valuable metals, such as lead, zinc, and iron, as well as precious metals, such as gold and silver. Four materials, namely super-hot acid leach residue, a residue formed when super-hot acid leach residue is selectively leached for lead with triethylenetetramine, as well as flotation concentrate, and flotation tailings formed in a selective silver flotation process with super-hot acid leach residue as the feed material were characterized to obtain a deeper understanding of possible further metal extraction. These four materials were characterized for chemical composition, mineralogy, and mineral distribution via chemical analyses, X-ray diffraction, and energy-dispersive scanning electron microscopy, respectively. The scanning electron microscope images showed that the materials have large variations in particle size distribution and composition. The results showed that the main lead phase in super-hot acid leach residue is lead sulfate, whereas it is mostly converted to lead sulfide during the selective lead leaching of the super-hot acid leach residue. The remaining lead sulfate is found in a solid solution with barium sulfate. Extracting lead from super-hot acid leach residue via triethylenetetramine leaching resulted in increased concentrations of gold and silver by 41% and 42%, respectively. The identified silver phases in super-hot acid leach residue may correspond to silver sulfide, silver chloride, and elementary silver, where silver sulfide was the most commonly occurring silver phase. After leaching this selectively for lead with triethylenetetramine, similar silver phases were identified, but silver sulfide and silver chloride occurred to a similar extent. Additionally, silver copper sulfide was detected. The presence of different silver phases might pose a challenge to reaching high silver recovery during leaching as the optimum leaching conditions differ somewhat. Furthermore, elemental sulfur, with a tendency to coat gold and silver particle surfaces, which is indicated to be present in all materials except the silver flotation tailings, may hinder metal extraction.

Place, publisher, year, edition, pages
Multidisciplinary Digital Publishing Institute (MDPI), 2024
Keywords
characterization for metal extraction, residue recycling, silver identification, super-hot acid leaching, zinc leaching residues
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-104168 (URN)10.3390/met14010073 (DOI)001151383500001 ()2-s2.0-85183369013 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-05 (joosat);

Funder: EIT Raw Materials, co-funded by European Union (19164); Boliden Mineral AB;

Full text license: CC BY

Available from: 2024-02-05 Created: 2024-02-05 Last updated: 2024-11-20Bibliographically approved
Elsadek, M., Ahmed, H., Suup, M., Sand, A., Heikkinen, E., Khoshkhoo, M. & Sundqvist-Öqvist, L. (2023). Recycling of pyrite and gypsum mining residues through thermochemical conversion into valuable products. Resources, Conservation and Recycling, 199, Article ID 107219.
Open this publication in new window or tab >>Recycling of pyrite and gypsum mining residues through thermochemical conversion into valuable products
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2023 (English)In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 199, article id 107219Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2023
National Category
Geochemistry
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-101825 (URN)10.1016/j.resconrec.2023.107219 (DOI)001159422000001 ()2-s2.0-85174184746 (Scopus ID)
Funder
VinnovaSwedish Research Council FormasSwedish Energy Agency
Note

Validerad;2023;Nivå 2;2023-10-30 (hanlid);

Funder: CAMM2 (Center for advanced mining & metallurgy), Luleå University of Technology

Available from: 2023-10-30 Created: 2023-10-30 Last updated: 2024-03-07Bibliographically approved
Hellgren, S., Engström, F. & Sundqvist-Öqvist, L. (2023). Silver Extraction from Residue Materials in the Zinc Industry by Thiourea Leaching. In: Proceedings - European Metallurgical Conference, EMC 2023: First Volume. Paper presented at 2023 European Metallurgical Conference (EMC 2023), Dusseldorf, Germany, June 11-14, 2023. GDMB
Open this publication in new window or tab >>Silver Extraction from Residue Materials in the Zinc Industry by Thiourea Leaching
2023 (English)In: Proceedings - European Metallurgical Conference, EMC 2023: First Volume, GDMB , 2023Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
GDMB, 2023
Series
Proceedings - European Metallurgical Conference, EMC 2023
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-103983 (URN)2-s2.0-85182920877 (Scopus ID)
Conference
2023 European Metallurgical Conference (EMC 2023), Dusseldorf, Germany, June 11-14, 2023
Note

ISBN for host publication: 978-3-935797-35-1;

Available from: 2024-03-11 Created: 2024-03-11 Last updated: 2024-03-11Bibliographically approved
El-Tawil, A., Björkman, B., Lundgren, M. & Sundqvist Ökvist, L. (2023). The Effect of Bio-Coal Agglomeration and High-Fluidity Coking Coal on Bio-Coke Quality. Metals, 13(1), Article ID 175.
Open this publication in new window or tab >>The Effect of Bio-Coal Agglomeration and High-Fluidity Coking Coal on Bio-Coke Quality
2023 (English)In: Metals, ISSN 2075-4701, Vol. 13, no 1, article id 175Article in journal (Refereed) Published
Abstract [en]

Metallurgical coke with high strength and low reactivity is used in the ironmaking blast furnace. Replacement of some coking coal with bio-coal was shown to result in lower strength and higher reactivity of produced coke due to introduction of reactive bio-coal carbon and ash components catalyzing the Boudouard reaction, but also due to lowering of the coking coal blend fluidity, which influences coke strength and reactivity negatively. The current study aims to investigate the possibility to counteract negative impact from bio-coal addition on fluidity and coke reactivity by using high-fluidity coking coal and by agglomeration of bio-coal before addition. Original bio-coal and micro-agglomerate of bio-coal was added at 10%, 15% and 20% to the coking coal blend. The influence of bio-coals on the coke reactivity was measured by using CO2 in a thermogravimetric analyzer. Selected cokes and bio-cokes were produced in technical scale, and their reactivity and strength were measured in standard tests. The effect on dilatation of adding bio-coal or crushed agglomerates of bio-coal to the coking coal blends was measured in an optical dilatometer. The results show that by using a coking coal blend containing high-fluidity coal with agglomerated bio-coal, the max. contraction is increased, whereas the opposite occurs by using original bio-coal. The results show overlapping between contraction occurring before dilatation and during dilation, which affects max. dilatation. The bio-coke containing high-fluidity coal with agglomerated bio-coal has lower reactivity in comparison to bio-cokes with original bio-coal or bio-coke with agglomerated bio-coal produced from a coking coal blend without high-fluidity coal. The reactivity of coke produced in technical scale, as measured in CRI/CSR tests, shows a similar trend regarding reactivity, as measured by thermogravimetric analysis, on coke produced in laboratory scale.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
agglomerated bio-coal, bio-coke, high-fluidity coking coal, torrefied sawdust
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-95546 (URN)10.3390/met13010175 (DOI)000928392500001 ()2-s2.0-85146806548 (Scopus ID)
Funder
Swedish Research Council Formas, (FR-2018/0010)
Note

Validerad;2023;Nivå 2;2023-02-08 (joosat);

Licens fulltext: CC BY License

Available from: 2023-02-08 Created: 2023-02-08 Last updated: 2024-03-07Bibliographically approved
Andersson, A., Ahmed, H., Sundqvist Ökvist, L. & Björkman, B. (2021). Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments. In: : . Paper presented at The 11th International Conference on Molten Slags, Fluxes and Salts (MOLTEN 2021), Seoul, South Korea, Online, February 21-25, 2021.
Open this publication in new window or tab >>Evaluation of evaporation kinetics of potassium from synthetic blast furnace slag using full factorial design of experiments
2021 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

In the present work, a full factorial design of experiments with three factors was performed studying the evaporation of potassium (K) from synthetic blast furnace (BF) slag. The experiments showed that slag temperature and B2 basicity (%CaO/%SiO2) had the greatest effect on the evaporation kinetics, while the effect of the MgO content was comparatively less. The regression model developed based on the experimental design could describe the evaporation of K from actual BF slags fairly well, provided that they were within the experimental matrix of the design of experiments.

National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-88855 (URN)
Conference
The 11th International Conference on Molten Slags, Fluxes and Salts (MOLTEN 2021), Seoul, South Korea, Online, February 21-25, 2021
Available from: 2022-01-19 Created: 2022-01-19 Last updated: 2023-09-05Bibliographically approved
Sundqvist Ökvist, L. & Lundgren, M. (2021). Experiences of Bio-Coal Applications in the Blast Furnace Process—Opportunities and Limitations. Minerals, 11(8)
Open this publication in new window or tab >>Experiences of Bio-Coal Applications in the Blast Furnace Process—Opportunities and Limitations
2021 (English)In: Minerals, E-ISSN 2075-163X, Vol. 11, no 8Article in journal (Refereed) Published
Abstract [en]

Metal production, and especially iron ore-based steel production, is characterized by high fossil CO2 emissions due of the use of coal and coke in the blast furnace. Steel companies around the world are striving to reduce the CO2 emissions in different ways, e.g., by use of hydrogen in the blast furnace or by production of iron via direct reduction. To partially replace fossil coal and coke with climate neutral bio-coal products that are adapted for use in the metal industry, e.g., at the blast furnace, is a real and important opportunity to significantly lower the climate impact in a short-term perspective. Top-charging of bio-coal directly to the blast furnace is difficult due to its low strength but can be facilitated if bio-coal is added as an ingredient in coke or to the mix when producing residue briquettes. Bio-coal can also be injected into the lower part of the blast furnace and thereby replace a substantial part of the injected pulverized coal. Based on research work within Swerim, where the authors have been involved, this paper will describe the opportunities and limitations of using bio-coal as a replacement for fossil coal as part of coke, as a constituent in residue briquettes, or as replacement of part of the injected pulverized coal. Results from several projects studying these opportunities via technical scale, as well as pilot and industrial scale experiments and modelling will be presented. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
biomass, bio-coal, charcoal, reducing agent, briquettes, injection, coke
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-86841 (URN)10.3390/min11080863 (DOI)000689471900001 ()2-s2.0-85112058610 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-09-01 (johcin)

Available from: 2021-08-26 Created: 2021-08-26 Last updated: 2024-01-17Bibliographically approved
El-Tawil, A. A., Björkman, B., Lundgren, M., Robles, A. & Sundqvist Ökvist, L. (2021). Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity. Metals, 11(11), Article ID 1752.
Open this publication in new window or tab >>Influence of Bio-Coal Properties on Carbonization and Bio-Coke Reactivity
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2021 (English)In: Metals, ISSN 2075-4701, Vol. 11, no 11, article id 1752Article in journal (Refereed) Published
Abstract [en]

Coke corresponds to 2/3–3/4 of the reducing agents in BF, and by the partial replacement of coking coals with 5–10% of bio-coal, the fossil CO2 emissions from the BF can be lowered by ~4–8%. Coking coal blends with 5% and 10% additions of bio-coals (pre-treated biomass) of different origins and pre-treatment degrees were carbonized at laboratory scale and with a 5% bio-coal addition at technical scale, aiming to understand the impact on the bio-coal properties (ash amount and composition, volatile matter content) and the addition of bio-coke reactivity. A thermogravimetric analyzer (TGA) connected to a quadrupole mass spectroscope monitored the residual mass and off-gases during carbonization. To explore the effect of bio-coal addition on plasticity, optical dilatometer tests were conducted for coking coal blends with 5% and 10% bio-coal addition. The plasticity was lowered with increasing bio-coal addition, but pyrolyzed biomass had a less negative effect on the plasticity compared to torrefied biomasses with a high content of oxygen. The temperature for starting the gasification of coke was in general lowered to a greater extent for bio-cokes produced from coking coal blends containing bio-coals with higher contents of catalyzing oxides. There was no significant difference in the properties of laboratory and technical scale produced coke, in terms of reactivity as measured by TGA. Bio-coke produced with 5% of high temperature torrefied pelletized biomass showed a similar coke strength as reference coke after reaction.

Place, publisher, year, edition, pages
Minerals, Metals & Materials Society, 2021
Keywords
bio-coals, carbonization, gasification, reactivity, dilatation, fluidity
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-87770 (URN)10.3390/met11111752 (DOI)000725158000001 ()2-s2.0-85118196084 (Scopus ID)
Funder
Swedish Research Council FormasLuleå University of Technology, FR-2018/0010
Note

Validerad;2021;Nivå 2;2021-11-08 (beamah)

Available from: 2021-11-04 Created: 2021-11-04 Last updated: 2023-09-05Bibliographically approved
El-Tawil, A., Björkman, B., Lundgren, M., Bäck, F. & Sundqvist Ökvist, L. (2021). Influence of Modified Bio-Coals on Carbonization and Bio-Coke Reactivity. Metals, 12(1), Article ID 61.
Open this publication in new window or tab >>Influence of Modified Bio-Coals on Carbonization and Bio-Coke Reactivity
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2021 (English)In: Metals, ISSN 2075-4701, Vol. 12, no 1, article id 61Article in journal (Refereed) Published
Abstract [en]

Substitution of coal in coking coal blend with bio-coal is a potential way to reduce fossil CO2 emissions from iron and steelmaking. The current study aims to explore possible means to counteract negative influence from bio-coal in cokemaking. Washing and kaolin coating of bio-coals were conducted to remove or bind part of the compounds in the bio-coal ash that catalyzes the gasification of coke with CO2. To further explore how the increase in coke reactivity is related to more reactive carbon in bio-coal or catalytic oxides in bio-coal ash, ash was produced from a corresponding amount of bio-coal and added to the coking coal blend for carbonization. The reaction behavior of coals and bio-coals under carbonization conditions was studied in a thermogravimetric analyzer equipped with a mass spectrometer during carbonization. The impact of the bio-coal addition on the fluidity of the coking coal blend was studied in optical dilatometer tests for coking coal blends with and without the addition of bio-coal or bio-coal ash. The result shows that the washing of bio-coal will result in lower or even negative dilatation. The washing of bio-coals containing a higher amount of catalytic components will reduce the negative effect on bio-coke reactivity, especially with acetic acid washing when the start of gasification temperature is less lowered. The addition of bio-coal coated with 5% kaolin do not significantly lower the dilatation-relative reference coking coal blend. The reactivity of bio-cokes containing bio-coal coated with kaolin-containing potassium oxide was higher in comparison to bio-coke containing the original bio-coal. The addition of ash from 5% of torrefied bio-coals has a moderate effect on lowering the start of gasification temperature, which indicates that the reactive carbon originating from bio-coal has a larger impact.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
bio-coals, washing, kaolin, ash, coking, volatile matter
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-88709 (URN)10.3390/met12010061 (DOI)000747640300001 ()2-s2.0-85121723271 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-11 (johcin)

Available from: 2022-01-11 Created: 2022-01-11 Last updated: 2023-09-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3363-351X

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