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Feng, Y., Yang, Q., Chen, Q., Kero, J., Andersson, A., Ahmed, H., . . . Samuelsson, C. (2019). Characterization and evaluation of the pozzolanic activity of granulated copper slag modified with CaO. Journal of Cleaner Production, 232, 1112-1120
Open this publication in new window or tab >>Characterization and evaluation of the pozzolanic activity of granulated copper slag modified with CaO
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2019 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 232, p. 1112-1120Article in journal (Refereed) Published
Abstract [en]

GCS, granulated copper slag, is currently utilized in cement and concrete with a low rate, due mainly to its low pozzolanic activity. The present study was thus performed by first mixing the GCS with CaO, and then melting and water-granulating the GCS-CaO mixtures, as to enhance the reactivity of GCS. Blended cements were formulated by replacing 30 wt. % of the cement, PC, with the modified GCS. The addition of CaO in GCS increased the release rates of heat from the early-age hydration of the blended cement pastes. The pastes with CSC20, the GCS of the highest CaO content (19.5%), acquired higher compressive strengths than those for the PC and other PC-GCS pastes at both 28 and 90 days of curing. The GCS richer in CaO consumed more calcium hydroxide for the formation of calcium silicate hydrates, with SEM micrographs showing a microstructure of more gel phases and less pores in PC-GCS paste. These results indicate that the modification by addition of CaO is an effective way to achieve a high reactivity for the GCS. It may then be possible to utilize the modified GCS as a high-quality supplementary cementitious material to enhance the sustainability for both copper and cement industries.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-74404 (URN)10.1016/j.jclepro.2019.06.062 (DOI)000477784000095 ()2-s2.0-85067309016 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-17 (svasva)

Available from: 2019-06-12 Created: 2019-06-12 Last updated: 2019-08-20Bibliographically approved
Sar, S., Sundqvist Ökvist, L., Sparrman, T., Engström, F. & Samuelsson, C. (2019). Characterization of Double Leached Waelz Oxide for Identification of Fluoirde Mineral. Metals, 9(3), Article ID 361.
Open this publication in new window or tab >>Characterization of Double Leached Waelz Oxide for Identification of Fluoirde Mineral
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2019 (English)In: Metals, ISSN 2075-4701, Vol. 9, no 3, article id 361Article in journal (Refereed) Published
Abstract [en]

Double leached Waelz oxide (DLWO), with 76% zinc, is a secondary zinc containing raw materials obtained by the treatment of electric arc furnace dust. The content of fluoride in DLWO is still too high for direct leaching, as fluoride has a detrimental effect on electrowinning for zinc production. Knowledge of the characteristics of DLWO, and especially on how a fluoride mineral might exist, can contribute to further improvement of the selective leaching for the removal of fluoride. In this study, DLWO was characterized using analytical techniques, such as inductively coupled plasma-optical emission spectroscopy (ICP-OES), 19F liquid-state nuclear magnetic resonance (19F LS NMR), X-ray powder diffraction analysis (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and 19F solid-state nuclear magnetic resonance (19F SS NMR). This study showed that DLWO mainly consisted of zincite (ZnO), cerussite (PbCO3) and a spinel containing zinc, iron and manganese. The fluoride mineral identified was calcium fluoride (CaF2). In SEM analysis, fluorine was found in larger grains together with calcium and oxygen, which was possibly calcium carbonate.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
metal recycling; zinc secondary dust material; characterization of double leached Waelz oxide; halogens; fluoride identification
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73646 (URN)10.3390/met9030361 (DOI)000464321200002 ()2-s2.0-85064228809 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-04-16 (oliekm)

Available from: 2019-04-15 Created: 2019-04-15 Last updated: 2019-05-03Bibliographically approved
Brämming, M., Engström, F., Samuelsson, C. & Björkman, B. (2019). Characterization of Slag‐Metal Emulsion and Its Impact on Foaming Behavior and Slopping in the LD Process. Steel Research International, 90(2), Article ID 1800269.
Open this publication in new window or tab >>Characterization of Slag‐Metal Emulsion and Its Impact on Foaming Behavior and Slopping in the LD Process
2019 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 90, no 2, article id 1800269Article in journal (Refereed) Published
Abstract [en]

In the Basic Oxygen Steelmaking (BOS) process, a heterogeneous emulsion‐solid mix will form, consisting of an emulsion of liquid slag and metal droplets, in which 2nd phase particles of undissolved fluxes and solid in‐blow precipitates are suspended. When the carbon in the metal droplets reacts with iron oxide, small bubbles of CO gas are formed. If the upward movement of these bubbles is obstructed by the physical properties of the emulsion‐solid mix, foaming will occur. Certain process conditions may lead to an excessive foam growth, in the worst case forcing foam out of the vessel. This undesired process event is known as “slopping”. Extensive studies during recent decades have shown that emulsion characteristics strongly connected to foaming are: viscosity, surface tension, and density. The extent of foaming is also dependent on bubble size; foaming increasing with smaller bubble size. However, investigations into the influence of the mineralogy and morphology of the emulsion‐solid mix on foaming in basic oxygen steelmaking are scarce. In this work, samples from trials in a 6‐tonne pilot plant BOS vessel are examined by XRD and with SEM for the determination of emulsion‐solid mix mineralogy and morphology at different stages of the oxygen blow. The study confirms the importance of tight process control in order to minimize the emulsion‐solid mix apparent viscosity and, hence, the foam height, but this without over‐oxidizing the liquid slag phase, which would result in increased gas generation within the slag‐metal emulsion.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
sic oxygen steelmaking (BOS), emulsion characterization, foaming, LD process, mineralogy, morphology, slopping
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-72759 (URN)10.1002/srin.201800269 (DOI)000458361600016 ()2-s2.0-85058014454 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-06 (johcin) 

Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-03-08Bibliographically approved
Lotfian, S., Ahmed, H., Umeki, K. & Samuelsson, C. (2019). Conversion Characteristics of Alternative Reducing Agents for the Bath Smelting Processes in an Oxidizing Atmosphere. Journal of Sustainable Metallurgy, 5(2), 230-239
Open this publication in new window or tab >>Conversion Characteristics of Alternative Reducing Agents for the Bath Smelting Processes in an Oxidizing Atmosphere
2019 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 5, no 2, p. 230-239Article in journal (Refereed) Published
Abstract [en]

The amount of plastic-containing materials, such as shredder residue material, which is generated after the processing of electronic equipment waste, is increasing. One interesting option for the sustainable management of these materials, instead of incineration or landfilling, is recycling through injection in a bath smelting process, such as zinc fuming. In this way, the plastic material could partially substitute coal as a reductant in the process. In such processes, shredder residue material is injected alongside air into the furnace at temperatures up to 1250 °C. Once the material is injected, it undergoes several conversion steps, including ignition, devolatilization, and char oxidation. In this study, the conversions of shredder residue material and other pure plastic materials were investigated using a drop tube furnace and an optical single-particle burner. The effect of particle size on the conversion time of each material was studied. The conversion time of the particles increases as the particle size increases, although the relationship is not linear. The results indicate that plastic materials with a particle size range of 1–7 mm have a considerably longer conversion time than that of coal used in the conventional processes.

Place, publisher, year, edition, pages
New York: Springer, 2019
Keywords
Shredder residue materials, Thermal conversion, Oxidizing conditions, Drop tube furnace, Optical single- particle burner
National Category
Metallurgy and Metallic Materials Energy Engineering
Research subject
Process Metallurgy; Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73269 (URN)10.1007/s40831-019-00217-x (DOI)000471200800009 ()2-s2.0-85062709413 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-01 (johcin)

Available from: 2019-03-20 Created: 2019-03-20 Last updated: 2019-07-01Bibliographically approved
Lotfian, S., Vikström, T., Lennartsson, A., Björkman, B., Ahmed, H. & Samuelsson, C. (2019). Evaluating the potential of plastic-containing materials as alternative reducing agents. Canadian metallurgical quarterly
Open this publication in new window or tab >>Evaluating the potential of plastic-containing materials as alternative reducing agents
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2019 (English)In: Canadian metallurgical quarterly, ISSN 0008-4433, E-ISSN 1879-1395Article in journal (Refereed) Epub ahead of print
Abstract [en]

The amount of discarded plastic-containing materials is increasing, and one option to help with this issue is to use these materials in bath smelting processes. The injection of plastic-containing materials to partially substitute coal in zinc-fuming processes has been studied in an industrial trial at Boliden–Rönnskär smelter. To evaluate the potential of plastic-containing materials, thermodynamic calculations were performed in this study. In the first step, a thermodynamic calculation was performed for trials with only coal injection, and then this calculation was applied to trials with the co-injection of plastic materials. The thermodynamic calculation shows that not all the injected coal participates in the reactions within the slag. Similarly, the calculation with the co-injection of plastic-containing materials shows that different amounts of each plastic material participate in the reactions within the slag bath.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
base metal production, industrial trial, recycling, reducing agent, Shredder residue material, sustainable management, thermodynamic calculation
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73373 (URN)10.1080/00084433.2019.1590044 (DOI)000463333600001 ()
Available from: 2019-04-01 Created: 2019-04-01 Last updated: 2019-04-17
Feng, Y., Kero, J., Yang, Q., Chen, Q., Engström, F., Samuelsson, C. & Qi, C. (2019). Mechanical Activation of Granulated Copper Slag and Its Influence on Hydration Heat and Compressive Strength of Blended Cement. Materials, 12(5), Article ID 772.
Open this publication in new window or tab >>Mechanical Activation of Granulated Copper Slag and Its Influence on Hydration Heat and Compressive Strength of Blended Cement
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2019 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 5, article id 772Article in journal (Refereed) Published
Abstract [en]

Mechanical activation of granulated copper slag (GCS) is carried out in the present study for the purposes of enhancing pozzolanic activity for the GCS. A vibration mill mills the GCS for 1, 2, and 3 h to produce samples with specific surface area of 0.67, 1.03 and 1.37 m²/g, respectively. The samples are used to replace 30% cement (PC) to get 3 PC-GCS binders. The hydration heat and compressive strength are measured for the binders and derivative thermogravimetric /thermogravimetric analysis (DTG/TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) are used to characterize the paste samples. It is shown that cumulative heat and compressive strength at different ages of hydration and curing, respectively, are higher for the binders blending the GCS milled for a longer time. The compressive strength after 90 d of curing for the binder with the longest milling time reaches 35.7 MPa, which is higher than the strength of other binders and close to the strength value of 39.3 MPa obtained by the PC pastes. The percentage of fixed lime by the binder pastes at 28 days is correlated with the degree of pozzolanic reaction and strength development. The percentage is higher for the binder blending the GCS with longer milling time and higher specific surface area. The pastes with binders blending the GCS of specific surface area of 0.67 and 1.37 m²/g fix lime of 15.20 and 21.15%, respectively. These results together with results from X-ray diffraction (XRD), FTIR, and SEM investigations demonstrate that the mechanical activation via vibratory milling is an effective method to enhance the pozzolanic activity and the extent for cement substitution by the GCS as a suitable supplementary cementitious material (SCM).

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2019
Keywords
blended cement paste; compressive strength; fineness; granulated copper slag; mechanical activation; pozzolanic activity
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73164 (URN)10.3390/ma12050772 (DOI)000462543700088 ()30845730 (PubMedID)
Note

Validerad;2019;Nivå 2;2019-03-12 (inah)

Available from: 2019-03-12 Created: 2019-03-12 Last updated: 2019-06-28Bibliographically approved
Lotfian, S., Vikström, T., Lennartsson, A., Björkman, B., Ahmed, H. & Samuelsson, C. (2019). Plastic-containing materials as alternative reductants for base metal production. Canadian metallurgical quarterly, 58(2), 164-176
Open this publication in new window or tab >>Plastic-containing materials as alternative reductants for base metal production
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2019 (English)In: Canadian metallurgical quarterly, ISSN 0008-4433, E-ISSN 1879-1395, Vol. 58, no 2, p. 164-176Article in journal (Refereed) Published
Abstract [en]

Shredder residue materials are produced after the removal of ferrous and non-ferrous fractions from end-of-life electronic equipment. Despite the high plastic content and metal value in the ash, high percentages of these materials are currently sent to landfills. In this study, the potential of utilising shredder residue material and other plastic-containing materials as reducing agents was studied. Plastic-containing materials were co-injected with coal into a zinc-fuming furnace in Boliden-Rönnskär smelter. The data obtained from the trial, such as the data from the chemical analysis of the slag and the steam production, are discussed. The observations indicate that plastic-containing material can replace up to 1 ton h−1 of coal without a significant decrease in the zinc reduction rate.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Shredder residue material, reducing agent, sustainable, base metal production, zinc-fuming, industrial trial, recycling, plastic-containing materials, slag
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73665 (URN)10.1080/00084433.2018.1532951 (DOI)000466443300005 ()2-s2.0-85063106067 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-17 (johcin)

Available from: 2019-04-15 Created: 2019-04-15 Last updated: 2019-06-17Bibliographically approved
Lennartsson, A., Engström, F., Björkman, B. & Samuelsson, C. (2019). Understanding the bottom buildup in an electric copper smelting furnace by thermodynamic calculations. Canadian metallurgical quarterly, 58(1), 89-95
Open this publication in new window or tab >>Understanding the bottom buildup in an electric copper smelting furnace by thermodynamic calculations
2019 (English)In: Canadian metallurgical quarterly, ISSN 0008-4433, E-ISSN 1879-1395, Vol. 58, no 1, p. 89-95Article in journal (Refereed) Published
Abstract [en]

Thermodynamic calculations were used to investigate the liquidus temperature of the slag and the possible influence on the buildup formation in an electric copper smelting furnace. The impact of parameters such as Fe/SiO2 ratio, partial pressure of oxygen and the content of the oxides ZnO, Al2O3 and Cr2O3 in the slag were investigated with respect to the liquidus temperature of the slag. Results show that the chromium content in the slag has the greatest impact on the liquidus temperature and on the formation of solid particles. The characterization of the buildup done earlier showed that spinel phases were among the dominating phases. This is supported by the thermodynamic calculations in the present paper, where the chromite solid solution was found to be the primary precipitation phase.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2019
Keywords
Copper smelting, FactSage, Buildup, Thermodynamic calculation, Spinel, Pyrometallurgy, Electric furnace
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-70765 (URN)10.1080/00084433.2018.1518804 (DOI)000452743200008 ()2-s2.0-85053228724 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-01-30 (inah)

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2019-01-30Bibliographically approved
Andersson, A. (2019). Upgrading of Blast Furnace Sludge and Recycling of the Low‑Zinc Fraction via Cold‑bonded Briquettes. Journal of Sustainable Metallurgy
Open this publication in new window or tab >>Upgrading of Blast Furnace Sludge and Recycling of the Low‑Zinc Fraction via Cold‑bonded Briquettes
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2019 (English)In: Journal of Sustainable Metallurgy, ISSN 2199-3823Article in journal (Refereed) Epub ahead of print
Abstract [en]

Depending on the operation of the blast furnace (BF), the main outlet of zinc from the furnace is more or less via the BF dust and sludge. As the dust is recycled to the BF, the sludge has to be de-zinced prior to recycling to prevent the accumulation of zinc in the BF. De-zincing and recycling of the low-zinc fraction via sinter have been reported. However, no research con-cerning recycling of upgraded BF sludge via cold-bonded briquettes has been performed. In the present study, a fine-grained BF sludge with low zinc content, generated by a BF operating on a ferrous burden of 100% pellets, was upgraded using the tornado process. The process simultaneously dried and separated the BF sludge into a high-zinc and a low-zinc fraction. The feasibility of recycling the low-zinc fraction to the BF using cold-bonded briquettes was studied on a laboratory-scale BF shaft simulator. On comparison with a reference briquette, the experiments indicated that 10 wt% of the upgraded BF sludge can be added to the briquette without negatively affecting the reducibility. Higher additions were found to render the briquette less reduced compared to the reference under test conditions corresponding to the central part of the BF. The strength of the briquettes was not compromised with the addition of the upgraded BF sludge, and a decision to study the briquettes in the LKAB experimental blast furnace was made in order to evaluate the behavior under actual BF conditions.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Blast furnace sludge, Recycling, Upgrading, De-zincing, Cold-bonded briquettes, Laboratory-scale blast furnace
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-73899 (URN)10.1007/s40831-019-00225-x (DOI)2-s2.0-85065727551 (Scopus ID)
Funder
Swedish Energy Agency, JK21069
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-08-22
Lotfian, S., Ahmed, H. & Samuelsson, C. (2017). Alternative reducing agents in metallurgical processes: devolatilization of Shredder Residue Materials. Journal of Sustainable metallurgy, 3(2), 311-321
Open this publication in new window or tab >>Alternative reducing agents in metallurgical processes: devolatilization of Shredder Residue Materials
2017 (English)In: Journal of Sustainable metallurgy, ISSN 2199-3823, Vol. 3, no 2, p. 311-321Article in journal (Refereed) Published
Abstract [en]

Plastic-containing shredder residue material has the potential to be used as an alternative reducing agent in nonferrous bath smelting processes. This would lead to not only decreased dependency on primary sources such as coal or coke but also to an increase in the efficiency of utilization of secondary sources. This calls for systematic scientific investigations, wherein these secondary sources are compared with primary sources with respect to devolatilization characteristics, combustion characteristics, reactivity, etc. As a first step, in this paper, devolatilization characteristics of plastic-containing shredder residue material (SRM) are compared to those of coal using thermogravimetric analysis. Proximate analysis has shown that SRM mainly decomposes by release of volatiles, while coal shows high fixed carbon content, which is reported to contribute to reduction reactions. To study the reduction potential of the evolved materials, composition of evolved off-gas was continuously monitored using quadrupole mass spectroscopy. The composition of volatiles shows H2, CO, and hydrocarbons which are known to have reduction potential. Therefore, it is essential that SRM would be used in a process that could utilize the evolved volatiles for reduction. Furthermore, to understand the potentials of different plastic materials as reducing agents, the devolatilization mechanisms and volatile composition of three common plastics, namely, polyethylene, polyurethane, and polyvinylchloride and their mixtures have been studied. The results show the interaction between the plastics within the binary and ternary mixtures. Similar phenomena may occur during devolatilization of SRM, which contains different type of plastics. 

Place, publisher, year, edition, pages
Springer, 2017
National Category
Metallurgy and Metallic Materials
Research subject
Process Metallurgy
Identifiers
urn:nbn:se:ltu:diva-60056 (URN)10.1007/s40831-016-0094-0 (DOI)000400824500012 ()
Note

Validerad; 2017; Nivå 2; 2017-05-12 (andbra)

Available from: 2016-10-31 Created: 2016-10-31 Last updated: 2018-09-14Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1511-8020

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