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Stener, Jan
Publications (10 of 23) Show all publications
Sand, A., Stener, J., Toivakka, M., Carlson, J. & Pålsson, B. (2016). A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions (ed.). Paper presented at Computational Modelling '15 : 08/06/2015 - 10/06/2015. Minerals Engineering, 90(SI ), 70-76
Open this publication in new window or tab >>A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions
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2016 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 90, no SI , p. 70-76Article in journal (Refereed) Published
Abstract [en]

The dynamic behaviour of μm-scale ferromagnetic particles in suspension is of interest for various mineral beneficiation processes. It is, however, difficult to experimentally study such processes at the particle-level. In these instances it can be advantageous to resort to suitable particle simulation methods.Stokesian dynamics is a mesh-free numerical technique developed for suspensions of nm to mm size particles. The method inherently considers hydrodynamic interactions, but additional interaction models can be included depending on the system under investigation. We here present a Stokesian dynamics (SD) implementation, which allows for simulation of the motion of suspended magnetic particles in presence of an external magnetic field. The magnetic interaction model includes particle-field interactions as well as pairwise interactions between magnetised particles.Simulations are compared with experiments using a laboratory-scale flow cell. The method is shown to be realistic for studying ferromagnetic suspensions in mineral processing applications, and can be useful in understanding and predicting the efficiency of mineral separation processes.

National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-27464 (URN)10.1016/j.mineng.2015.10.015 (DOI)000375169200007 ()2-s2.0-84960865330 (Scopus ID)0eda3225-823b-4369-91a2-78b07835122b (Local ID)0eda3225-823b-4369-91a2-78b07835122b (Archive number)0eda3225-823b-4369-91a2-78b07835122b (OAI)
Conference
Computational Modelling '15 : 08/06/2015 - 10/06/2015
Note
Validerad; 2016; Nivå 1; 20151102 (andbra); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Stener, J., Carlson, J. E., Pålsson, B. & Sand, A. (2016). Direct measurement of internal material flow in a bench scale wet Low-Intensity Magnetic Separator (ed.). Paper presented at Physical Separation '15 : 11/06/2015 - 12/06/2015. Minerals Engineering, 91, 55-65
Open this publication in new window or tab >>Direct measurement of internal material flow in a bench scale wet Low-Intensity Magnetic Separator
2016 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 91, p. 55-65Article in journal (Refereed) Published
Abstract [en]

In this work an ultrasound-based measurement method is used formonitoring suspension velocity and build-up of magnetic material inside awet Low-Intensity Magnetic Separator, a process used e.g. inbeneficiation of magnetite ores. Today the only available option is tomonitor material transport between unit operations; i.e. flow rate,solids concentration, and particle size distribution of suspension flowin pipes are measured online using standard equipment.An Acoustic Backscatter System is fitted to the tank of a separator, andused to monitor the internal flow. A method called Ultrasonic VelocityProfiling is used to capture internal velocity profiles. Simultaneously,the backscatter signal intensity is used to get indications about localsolids concentration of the flow, and build-up of magnetic material. Themethods are evaluated in realistic conditions, where the effect ofvarying factors relevant to machine performance is investigated. Theincluded factors are; the slurry feed rate, the slurry solidsconcentration, the magnet assembly angle, and the drum rotational speed.The presented method gives useful information about the internal materialflow inside the separator. The velocity measurements capture the,sometimes complex, internal flow patterns, for example the presence andvelocity of a recirculating flow in the dewatering zone. Additionally,keeping a balanced material loading in the concentrate dewatering zone isimportant to separator performance. Using the signal backscatterintensity it is possible to qualitatively monitor this material loading.Generally these direct measurements can aid in improvements to machinedesign, process optimization, and process control.

National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-29949 (URN)10.1016/j.mineng.2015.10.021 (DOI)000375513500006 ()2-s2.0-84977914569 (Scopus ID)395c8b74-5c0d-42d1-9239-9141cede269c (Local ID)395c8b74-5c0d-42d1-9239-9141cede269c (Archive number)395c8b74-5c0d-42d1-9239-9141cede269c (OAI)
Conference
Physical Separation '15 : 11/06/2015 - 12/06/2015
Projects
Wet LlMS - Measurements and models
Note
Validerad; 2016; Nivå 1; 20151007 (janste); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Stener, J., Carlson, J., Sand, A. & Pålsson, B. (2016). Internal flow measurements in pilot scale wet low-intensity magnetic separation (ed.). International Journal of Mineral Processing, 155, 55-63
Open this publication in new window or tab >>Internal flow measurements in pilot scale wet low-intensity magnetic separation
2016 (English)In: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 155, p. 55-63Article in journal (Refereed) Published
Abstract [en]

In the mining industry, ferromagnetic particles (e.g. magnetite) are concentrated using wet low-intensity magnetic separation (LIMS). The performance is to a large extent controlled by the internal flow conditions in the separator. In previous work, it was shown how an ultrasound pulse-echo setup can be used to simultaneously measure particle velocity profiles and local solids concentration variations in laboratory conditions. In this paper, a real-world case is demonstrated where the system is installed on one of the wet LIMS at the LKAB R&D facilities in Malmberget, Sweden. For the pilot scale experiments a setup with two ultrasound transducers, mounted at the bottom of the separator tank, is used. The design of experiments method is used to study the effects of the feed solids concentration, drum rotational speed, position of the concentrate weir, and the magnet assembly angle on the measured flow patterns. The results show that it is possible to detect changes in the flow velocity patterns and the local solids concentration, as the operational conditions of the separator are varied. Of the factors studied, the drum rotational speed has the strongest influence on the overall flow velocity in the dewatering zone. Also, the presence of a recirculating flow transporting gangue particles away from the concentrate is confirmed. The factor with the strongest influence on this recirculating flow is also the drum rotational speed, together with the magnet assembly angle. Using this method it is possible to make high quality measurements of internal flow velocity profiles. It is also possible to monitor material build-up on the separator drum, and e.g. detect overload of magnetic material. The insights gained, and the methods developed, have generated new possibilities to control, optimise, and develop the wet LIMS process.

National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-8750 (URN)10.1016/j.minpro.2016.08.008 (DOI)000385472200006 ()2-s2.0-84983739058 (Scopus ID)749242bb-1c30-49e4-9d11-2910e9ad6cd7 (Local ID)749242bb-1c30-49e4-9d11-2910e9ad6cd7 (Archive number)749242bb-1c30-49e4-9d11-2910e9ad6cd7 (OAI)
Projects
Wet LlMS - Measurements and models
Note

Validerad; 2016; Nivå 2; 20160812 (janste)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Stener, J., Carlson, J., Sand, A. & Pålsson, B. (2016). Monitoring Mineral Slurry Flow using Pulse-Echo Ultrasound (ed.). Flow Measurement and Instrumentation, 50, 135-146
Open this publication in new window or tab >>Monitoring Mineral Slurry Flow using Pulse-Echo Ultrasound
2016 (English)In: Flow Measurement and Instrumentation, ISSN 0955-5986, E-ISSN 1873-6998, Vol. 50, p. 135-146Article in journal (Refereed) Published
Abstract [en]

Ultrasound based flow measurement methods have a large potential for the mining industry and its processing plants. Ultrasound travel through dense suspensions and is not affected by the magnetic fields sometimes present in this type of equipment.A cross-correlation based method is used for localized particle velocity measurements in one and two dimensions. Simultaneously, using the same data, information about local particle concentration is extracted from the power spectral density of the backscattered signal. Experiments are carried out both in simplified geometry and in full scale equipment in an iron ore pilot benefication plant.In the simple geometry it is possible to assess the precision of the methods by comparing the measurements to theory and numerical simulations. The results from the pilot plant experiments show that these methods can be applied to real world processes

National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-11762 (URN)10.1016/j.flowmeasinst.2016.06.022 (DOI)000383826800015 ()2-s2.0-84978027775 (Scopus ID)ac5e0544-9c34-42c3-b92f-16cc7bb885fe (Local ID)ac5e0544-9c34-42c3-b92f-16cc7bb885fe (Archive number)ac5e0544-9c34-42c3-b92f-16cc7bb885fe (OAI)
Note

Validerad; 2016; Nivå 2; 20160627 (johanc)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Sand, A., Stener, J., Toivakka, M., Carlson, J. & Pålsson, B. (2015). A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions (ed.). In: (Ed.), (Ed.), Proceedings of Computational Modelling 2015: Minerals Engineering International. Paper presented at Computational Modelling '15 : 08/06/2015 - 10/06/2015.
Open this publication in new window or tab >>A Stokesian Dynamics Approach for Simulation of Magnetic Particle Suspensions
Show others...
2015 (English)In: Proceedings of Computational Modelling 2015: Minerals Engineering International, 2015Conference paper, Published paper (Refereed)
National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-38546 (URN)cfa58820-571b-4a5f-8be4-94f6ed452f0c (Local ID)cfa58820-571b-4a5f-8be4-94f6ed452f0c (Archive number)cfa58820-571b-4a5f-8be4-94f6ed452f0c (OAI)
Conference
Computational Modelling '15 : 08/06/2015 - 10/06/2015
Note
Godkänd; 2015; 20150623 (andsan)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-02-28Bibliographically approved
Stener, J., Carlson, J. E., Pålsson, B. & Sand, A. (2015). Direct measurement of internal material flow in bench scale wet Low-Intensity Magnetic Separator (ed.). In: (Ed.), (Ed.), Proceedings of Physical Separation '15: . Paper presented at Physical Separation '15 : 11/06/2015 - 12/06/2015. : Minerals Engineering International
Open this publication in new window or tab >>Direct measurement of internal material flow in bench scale wet Low-Intensity Magnetic Separator
2015 (English)In: Proceedings of Physical Separation '15, Minerals Engineering International , 2015Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Minerals Engineering International, 2015
National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-28052 (URN)1b32904d-f22f-4aed-88fa-f2aae8c63c57 (Local ID)1b32904d-f22f-4aed-88fa-f2aae8c63c57 (Archive number)1b32904d-f22f-4aed-88fa-f2aae8c63c57 (OAI)
Conference
Physical Separation '15 : 11/06/2015 - 12/06/2015
Note
Godkänd; 2015; 20150210 (janste)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-02-28Bibliographically approved
Carlson, J., Stener, J., Sand, A. & Pålsson, B. (2015). In-Situ Monitoring of Particle Velocities and Solids Concentration Variations in wet Low-Intensity Magnetic Separators (ed.). In: (Ed.), (Ed.), 2015 IEEE International Ultrasonics Symposium, IUS 2015: Taipei, 21-24 Oct. 2015. Paper presented at IEEE International Ultrasonics Symposium : 21/10/2015 - 24/10/2015. Piscataway, NJ: IEEE Communications Society, Article ID 7329339.
Open this publication in new window or tab >>In-Situ Monitoring of Particle Velocities and Solids Concentration Variations in wet Low-Intensity Magnetic Separators
2015 (English)In: 2015 IEEE International Ultrasonics Symposium, IUS 2015: Taipei, 21-24 Oct. 2015, Piscataway, NJ: IEEE Communications Society, 2015, article id 7329339Conference paper, Published paper (Refereed)
Abstract [en]

In previous work, we have shown how an ultrasound pulse-echo setup can be used to simultaneously measure particle velocity profiles and local solids concentration variations in solid/liquid particle suspensions. In this paper, we demonstrate a real-world case where the system is installed in a wet low-intensity magnetic separator, a process in which magnetic material is separated from gangue. The method was evaluated at LKAB's R&D facilities in Malmberget, Sweden, on one of their pilot scale separators. The results show that it is possible to detect changes in the flow velocity patterns and the local solids concentration, as the operational conditions of the separator are varied.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2015
Series
Proceedings - IEEE Ultrasonics Symposium, ISSN 1948-5719
National Category
Signal Processing Metallurgy and Metallic Materials
Research subject
Signal Processing; Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-34920 (URN)10.1109/ULTSYM.2015.0274 (DOI)000366045700262 ()2-s2.0-84962033784 (Scopus ID)93acc895-236d-4d8e-bbca-29f37621598a (Local ID)978-1-4799-8182-3 (ISBN)93acc895-236d-4d8e-bbca-29f37621598a (Archive number)93acc895-236d-4d8e-bbca-29f37621598a (OAI)
Conference
IEEE International Ultrasonics Symposium : 21/10/2015 - 24/10/2015
Note
Validerad; 2016; Nivå 1; 20151207 (johanc)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Carlson, J., Stener, J., Sand, A. & Pålsson, B. (2015). Monitoring local solids fraction variations in multiphase flow using pulse-echo ultrasound (ed.). Paper presented at International Congress on Ultrasonics : 10/05/2015 - 15/05/2015. Physics Procedia, 70, 376-379
Open this publication in new window or tab >>Monitoring local solids fraction variations in multiphase flow using pulse-echo ultrasound
2015 (English)In: Physics Procedia, ISSN 1875-3892, E-ISSN 1875-3892, Vol. 70, p. 376-379Article in journal (Refereed) Published
Abstract [en]

This paper presents an ultrasonic pulse-echo technique for on-line monitoring of variations in solids concentrations in particlesuspensions. The method is based on time-frequency analysis of the backscatter signals, exploring variations in spectral content ofthe backscatter as function of depth in the suspension. Experiments on a settling of magnetite particles in water, at varying solidsconcentrations, show that the settling process can be followed by studying the energy of backscattered ultrasound.

National Category
Signal Processing Metallurgy and Metallic Materials
Research subject
Signal Processing; Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-31736 (URN)10.1016/j.phpro.2015.08.097 (DOI)000380533000090 ()2-s2.0-84948683249 (Scopus ID)5fee7adf-21ab-4eaa-992c-731074f6801f (Local ID)5fee7adf-21ab-4eaa-992c-731074f6801f (Archive number)5fee7adf-21ab-4eaa-992c-731074f6801f (OAI)
Conference
International Congress on Ultrasonics : 10/05/2015 - 15/05/2015
Note
Validerad; 2015; Nivå 1; 20150920 (johanc); Konferensartikel i tidskriftAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Sand, A., Stener, J., Toivakka, M., Carlson, J. & Pålsson, B. (2015). Simulation of Magnetic Particle Suspensions Using the Stokesian Dynamics Technique (ed.). In: (Ed.), (Ed.), Proceedings of Conference in Minerals Engineering 2015: . Paper presented at Conference in Minerals Engineering 2015 : 03/02/2015 - 04/02/2015. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Simulation of Magnetic Particle Suspensions Using the Stokesian Dynamics Technique
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2015 (English)In: Proceedings of Conference in Minerals Engineering 2015, Luleå: Luleå tekniska universitet, 2015Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2015
National Category
Metallurgy and Metallic Materials Signal Processing
Research subject
Mineral Processing; Signal Processing
Identifiers
urn:nbn:se:ltu:diva-34249 (URN)8643c006-e1f4-4594-b2ba-eb08ea9f77ea (Local ID)8643c006-e1f4-4594-b2ba-eb08ea9f77ea (Archive number)8643c006-e1f4-4594-b2ba-eb08ea9f77ea (OAI)
Conference
Conference in Minerals Engineering 2015 : 03/02/2015 - 04/02/2015
Note
Godkänd; 2015; 20150623 (andsan)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-02-28Bibliographically approved
Jonsén, P., Stener, J., Pålsson, B. & Häggblad, H.-Å. (2015). Validation of a model for physical interactions between pulp, charge and mill structure in tumbling mills (ed.). Paper presented at . Minerals Engineering, 73, 77-84
Open this publication in new window or tab >>Validation of a model for physical interactions between pulp, charge and mill structure in tumbling mills
2015 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 73, p. 77-84Article in journal (Refereed) Published
Abstract [en]

Modelling the pulp fluid and its simultaneous interactions with both the charge and the mill structure is an interesting challenge. The interactions have previously been modelled for dry grinding with a combination of discrete element method (DEM), smoothed particle hydrodynamics (SPH) and the finite element method (FEM), where the DEM particles or SPH particles represent the grinding balls and FEM is used to model the mill structure. In this work, the previous model is extended to include fluids with SPH. Wet milling with water and a magnetite pulp, for graded and mono-size charges are numerically modelled and validated. The internal working of the charge and the physical interaction between the charge and the mill structure is studied. The combined SPH–DEM–FEM model presented here can predict the classical DEM results, but can also predict responses from the mill structure, as well as the pulp liquid flow and pressure. Validation is conducted by comparing numerical results with experimental measurements from grinding in an instrumented small-scale batch ball mill equipped with an accurate torque metre. The simulated charge movement is also compared with high speed video of the charge movement for a number of cases. Numerical results are in good agreement with experimental measurements

National Category
Applied Mechanics Metallurgy and Metallic Materials
Research subject
Solid Mechanics; Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-10508 (URN)10.1016/j.mineng.2014.09.014 (DOI)000352248900010 ()2-s2.0-84923572235 (Scopus ID)951b5631-d745-47a0-98da-d6afb920e430 (Local ID)951b5631-d745-47a0-98da-d6afb920e430 (Archive number)951b5631-d745-47a0-98da-d6afb920e430 (OAI)
Note
Validerad; 2015; Nivå 2; 20141021 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
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