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  • 1.
    Beattie, D.A.
    et al.
    Ian Wark Research Institute, University of South Australia.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    In situ total internal reflection Raman spectroscopy of surfactant adsorption at a mineral surface2006In: Vibrational Spectroscopy, ISSN 0924-2031, E-ISSN 1873-3697, Vol. 41, no 2, p. 198-204Article in journal (Refereed)
    Abstract [en]

    We present the first attempt to characterise surfactant adsorption from solution onto a particle film using total internal reflection Raman spectroscopy. Three surfactant collectors of interest to the mineral processing industry were studied in their adsorption onto sphalerite: heptyl xanthate, 2-mercaptobenzothiazole (MBT), and O,O-dibutyldithiophosphate (DTP). All three surfactants adsorbed to the surface of the sphalerite. Adsorption of heptyl xanthate was monitored as a function of time and increasing concentration. The spectrum of heptyl xanthate indicated the presence of a small amount of dixanthogen on the surface of the sphalerite. MBT adsorption studies were complicated due to the fluorescence of the adsorbed layer. However, peaks due to the adsorbed MBT were observed on top of the fluorescent background, allowing the identification of the adsorbed species to be confirmed as the oxidised dimer species. Spectra obtained from MBT and DTP co-adsorption studies did not display the strong adsorbate layer fluorescence, indicating that the fluorescence spectrum of the adsorbed MBT is most likely affected by ring-ring interactions.

  • 2.
    Diener, Silvia
    et al.
    Dresden University of Technology.
    Andreas, Lale
    Herrmann, Inga
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Mineral phases in steel industry slags used in a landfill cover constuction2006In: Abstract proceedings of the 4th Intercontinental Landfill Research Symposium, , [June 14th to 16th 2006, Gällivare, Sweden] / [ed] Anders Lagerkvist, Luleå: Luleå tekniska universitet, 2006, p. 73-74Conference paper (Other academic)
  • 3.
    Engström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Lidström-Larsson, Margareta
    Samuelsson, Caisa
    Björkman, Bo
    Ageing investigation of steel slags from EAF (Electric Arc Furnace) processes2008In: REWAS 2008: Global Symposium on Recycling, Waste Treatment and Clean Technology / [ed] B Mishra; C Ludwig; S Das, Minerals, Metals & Materials Society, 2008, p. 353-358Conference paper (Refereed)
    Abstract [en]

    Large amounts of by-products are generated by the Swedish steel industry each year. The EAF-process generates about 400 000 ton of slag, from which 80% is deposit. An alternative to deposit is to use slag as road construction material. However, metal content in the slag can be a problem, due to the leaching. The aim of this work was to investigate how stable these materials are when ageing and kept outside. Five different EAF-slags from domestic steel plants were used in this study. The materials were characterised after 0, 6, 12, 18 and 24 month to evaluate the ageing process. Scanning electron microscope (SEM), x-ray diffraction pattern (XRD) and a standard test for leaching were used. The changes in behaviour differ between the five materials. The total leachability decreases with time for all samples. CaCO3 is formed on slag surfaces as CaO reacts with moister and CO2 in the air.

  • 4.
    Engström, Fredrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lidström-Larsson, Margareta
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Sandström, Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Robinson, Ryan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Leaching Behavior of Aged Steel Slags2014In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 85, no 4, p. 607-615Article in journal (Refereed)
    Abstract [en]

    Large amounts of slag are generated by the Swedish Steel Industry each year. The Electric Arc Furnace process generates about 200 000 ton of slag per annum, from which approximately 40% is deposited. An alternative to deposit is to use slag as road construction material. However, leaching of metals from the slag can be a reason to limit slag use in road construction. The aim of this work was to investigate how stable these materials are when aged, in an environment open to seasonable weather conditions, with respect to leaching and mineralogy. Three different EAF-slags from domestic steel plants were used in this study. The materials were characterized after 0, 6, 12, 18, and 24 months to evaluate the ageing process. The analytical techniques that were used to evaluate the effect of ageing are scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and a standard test for leaching. The changes in ageing behavior differ between the three materials. The conductivity and the pH decreases with time for all samples. The leaching of calcium, chromium as well as aluminum decreases with time while the leaching of magnesium increases. CaCO3 was formed on slag surfaces as CaO reacts with moisture and CO2 from the air.

  • 5. Fredriksson, Andreas
    et al.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Kinetics of xanthate adsorption on metal sulphides2004In: Konferens i mineralteknik / [ed] Marianne Thomaeus; Eric Forssberg, Föreningen Mineralteknisk Forskning / Swedish Mineral Processing Research Association , 2004Conference paper (Other academic)
  • 6. Fredriksson, Andreas
    et al.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    n-Heptyl xanthate adsorption on a ZnS layer synthesized on germanium: an in situ attenuated total reflection IR study2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 286, no 1, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Adsorption of n-heptyl xanthate on synthesized zinc sulfide was followed in situ by monitoring the methylene absorption band at 2925 cm-1. The zinc sulfide surface used in the adsorption experiments was synthesized on a germanium internal reflection element using the chemical bath deposition method. Characterization of the adsorbent surface was performed by X-ray photoelectron spectroscopy. The time needed to reach adsorption equilibrium varied with the initial concentration of the aqueous potassium heptyl xanthate solution. The amount of adsorbed xanthate ions increased with the concentration of the solution within the range studied (10 μM-50 mM). The experimental data are reasonably well described by the Langmuir adsorption isotherm. Polarized infrared attenuated total reflection (ATR) was used to determine the average orientation of the heptyl chains by measuring the absorbance of the infrared beam polarized perpendicularly and parallely to the plane of incidence. Measured absorbances were corrected for contribution from heptyl xanthate in bulk solution.

  • 7.
    Grahn, Mattias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Wang, Zheng
    Luleå tekniska universitet.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Sterte, Johan
    Silicalite-1 coated ATR elements as sensitive chemical sensor probes2005In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 81, no 1-3, p. 357-363Article in journal (Refereed)
    Abstract [en]

    A novel sensitive chemical sensor probe has been fabricated. The sensor principle is based on silicalite-1 coated ATR (attenuated total reflection) elements and FTIR spectroscopy. The microporous silicalite-1 film enriches the analyte to the probe surface, thus increasing the sensitivity. At a relative pressure of n-hexane in helium of 6 × 10−5 the sensitivity of the probe is approximately 85 times higher for the silicalite-1 coated element compared to a 10 cm transmission gas cell and ca. 180 times higher compared to an uncoated element. The performance of the probe is illustrated by determination of an adsorption isotherm for n-hexane in silicalite-1.

  • 8. Herrmann, Inga
    et al.
    Andreas, Lale
    Lidström-Larsson, Margareta
    Ecke, Holger
    Lagerkvist, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Reuse of steel industry slag in a landfill top cover2006In: Abstract proceedings of the 4th Intercontinental Landfill Research Symposium, [June 14th to 16th 2006, Gällivare, Sweden] / [ed] Anders Lagerkvist, Luleå: Luleå tekniska universitet, 2006, p. 88-89Conference paper (Other academic)
  • 9. Herrmann, Inga
    et al.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Gustafsson, G.
    Reuse of steel industry slags in landfill top cover constructions2005In: Securing the future: international conference on mining and the environment, metals and energy recovery : proceedings, Stockholm: SweMin , 2005, p. 409-416Conference paper (Other academic)
  • 10. Herrmann, Inga
    et al.
    Andreas, Lale
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lidström-Larsson, Margareta
    Lagerkvist, Anders
    Physical properties of steel slag to be reused in a landfill cover2005In: SARDINIA 2005: Tenth International Waste Management and Landfill Symposium ; S. Margerita di Pula, Sardinia, Italy, 3 - 7 October 2005 / [ed] Raffaello Cossu, Cagliari: CISA, Environmental Sanitary Engineering Centre , 2005Conference paper (Refereed)
  • 11.
    Holmgren, Allan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lidström-Larsson, Margareta
    Luleå University of Technology.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sterte, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Wang, Zheng
    Luleå University of Technology.
    Sensor for spectroscopic analysis of gases or liquids, comprises attenuated total reflection element with molecular sieve layerPatent (Other (popular science, discussion, etc.))
  • 12. Lidström-Larsson, Margareta
    Orientation of collectors adsorbed at the ZnS/solution interface2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The separation and concentration of minerals by flotation is a well-known industrial process. In this process collectors are used to increase the hydrophobicity of the surfaces of the minerals. Still there is a lot to find out about adsorption mechanism, organisation, and orientation of the adsorbed collectors, to be able to improve the characteristics of the collectors or to design new ones. In this work the organisation and orientation of sulphide mineral collectors adsorbed on a ZnS surface have been studied by the FTIR-ATR (attenuated total reflection) technique. The collectors used in this study are heptyl xanthate, O,O-dibutyldithiophosphate, and 2-mercaptobenzothiazole. The adsorbed collectors were studied both in contact with air and exposed to water. The orientation could be determined by using polarized light and the dichroic ratio. The adsorption and orientation of heptyl xanthate on germanium has also been studied, mainly because Ge is a suitable ATR-crystal on which ZnS or other sulphide minerals may be precipitated and used for future studies of mineral surfaces. In flotation copper activation is used to increase the flotability of minerals. How this affect the orientation, as well as how minimizing the oxygen content of the solutions affect the adsorption have been investigated. The alkyl chains of adsorbed heptyl xanthate tilted approximately 44 degrees from the normal of the surface when the adsorbed layer was in contact with air. When the adsorbed layer was in contact with water the tilt angle increased to about 50 degrees, and the order of the adsorbed layer decreased according to the shift of the asymmetric methylene stretch to higher frequency. Dixanthogen formed during the adsorption process on ZnS but not on Ge. The Germanium surface resulted in an adsorbed heptyl xanthate monolayer with the highest order and a tilt angle of about 47 degrees from the surface normal when the adsorbed layer was in contact with water. Besides the information on orientation of collectors this study has given knowledge about the coordination of xanthate to ZnS surfaces and reactions that may occur in the interface between minerals and water.

  • 13.
    Lidström-Larsson, Margareta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Sulphide mineral collectors adsorbed on a ZnS internal reflection element: an infrared linear dichroism study2000Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Separation and concentration of minerals by flotation is a well-known industrial process. In this process collector chemicals are used to modify the mineral surface to increase the hydrophobicity of the mineral particles. Still there is a lot to find out about adsorption mechanisms, orientation and organization of the adsorbed collectors on the surfaces to be able to improve the characteristics of the collectors or todesign new ones. In this work, the structure and orientation of sulphide mineral collectors adsorbed on a ZnS surface have been studied by the FTIR-ATR technique. The collectors that have been studied are heptylxanthate (R-CS2-, R = O-C7H15), O,O-dibutyldithiophosphate, 2-mercaptobenzothiazole and a mixture of 2-mercaptobenzothiazole and O,O-dibutyldithiophosphate. The adsorbed layer was prepared by self-assembly from solution or by spraying the solution onto the surfaces of the ATR-crystal for a short time. By using polarized light and the dichroic ratio a quantitative determination of the orientation of heptylxanthate could be performed. The tilt angle from the normal of the surface was found to be approximately 44 degrees. From the spectra it was concluded that the adsorbed species on the ZnS surface is a mixture between heptylxanthate and diheptyldixanthogen. A bridging coordination of the adsorbed heptylxanthate is proposed. The difference between the absorbance of the s-polarized light and p-polarized light was used to draw conclusions about the orientation of O,O-dibutyldithiophosphate and 2-mercaptobenzothiazole adsorbed on ZnS. The collectors are mixed in the flotation process and the influence on the orientation of O,O-dibutyldithiophosphate and 2-mercaptobenzothiazole when adsorbing from a mixture of the two collectors is also reported. In ATR-experiments very small amounts of substances are detected and problem due to contamination of the surfaces and the adsorbed thin film can be severe. Such problems encountered in the present work are described and discussed.

  • 14. Lidström-Larsson, Margareta
    et al.
    Fredriksson, Andreas
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Direct observation of a self-assembled monolayer of heptyl xanthate at the germanium/water interface: a polarized FTIR study2004In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 273, no 2, p. 345-349Article in journal (Refereed)
    Abstract [en]

    The adsorption of heptyl xanthate on germanium has been studied by the attenuated total reflection (ATR) technique. Polarized infrared light was used in situ to determine the average orientation of the alkyl chain in heptyl xanthate adsorbed at the germanium/solution interface. Spectra reveal the formation of closely packed xanthate ions with the alkyl chains in the all-trans conformation. The average tilt angle of the alkyl chains of heptyl xanthate was approximately 47° from the surface normal.

  • 15. Lidström-Larsson, Margareta
    et al.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Reversible phase transition in Zn₂(O,O-di(cyclohexyl)dithiophosphate)₄, studied by Raman spectroscopy and compared with NMR results2004In: Vibrational Spectroscopy, ISSN 0924-2031, E-ISSN 1873-3697, Vol. 34, no 2, p. 243-246Article in journal (Refereed)
    Abstract [en]

    It was recently shown by solid state ³¹P NMR spectroscopy that the number of phosphorous signals from the complex Zn₂(O,O-di(cyclohexyl)DTP)₄ varied reversibly with the temperature. According to the present study, Raman spectra of the same metal complex were also temperature dependent. Spectral features affected by the temperature changed reversibly upon raising and lowering the temperature. It was shown that conformational change of the hexyl rings and the P---O---C entities occurred in the temperature range between 40 and 55°C.

  • 16. Lidström-Larsson, Margareta
    et al.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Forsling, Willis
    Structure and orientation of collectors adsorbed at the ZnS/water interface2001In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 242, no 1, p. 25-30Article in journal (Refereed)
    Abstract [en]

    The adsorption of O,O-dibutyldithiophosphate and 2-mercaptobenzothiazole on the surface of ZnS has been studied by using the attenuated total reflection (ATR) technique. By utilizing polarized infrared radiation, we got qualitative information about the orientation of the adsorbed collectors. The difference between the absorbance of the s-polarized light and the absorbance of p-polarized light was used to draw conclusions about the orientation. The influence on the orientation of O,O-dibutyldithiophosphate and 2-mercaptobenzothiazole when adsorbing from a mixture of the two collectors is also reported, as well as the influence of these collectors on the hydrophobicity of the ZnS surface obtained by contact angle measurements.

  • 17. Lidström-Larsson, Margareta
    et al.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Forsling, Willis
    Xanthate adsorbed on ZnS studied by polarized FTIR-ATR spectroscopy2000In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 16, no 21, p. 8129-8133Article in journal (Refereed)
    Abstract [en]

    The structure and orientation of heptylxanthate adsorbed on a ZnS surface have been studied by the FTIR-ATR technique. By using polarized light and the dichroic ratio, we found the average tilt angle to be approximately 44 degrees. The adsorbed layer studied was prepared by self-assembly from solution or by spraying the solution onto the surfaces of the ATR crystal for a short time and then rinsing with water. From the spectra we can conclude that there is a mixture of adsorbed heptylxanthate and formed diheptyldixanthogen on the ZnS surface. A bridging coordination of the adsorbed heptylxanthate is proposed.

  • 18. Tossavainen, Mia
    et al.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Yang, Qixing
    Menad, Nourreddine
    Lidström-Larsson, Margareta
    Björkman, Bo
    Characteristics of steel slag under different cooling conditions2007In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 27, no 10, p. 1335-1344Article in journal (Refereed)
    Abstract [en]

    Four types of steel slags, a ladle slag, a BOF (basic oxygen furnace) slag and two different EAF (electric arc furnace) slags, were characterized and modified by semi-rapid cooling in crucibles and rapid cooling by water granulation. The aim of this work was to investigate the effect of different cooling conditions on the properties of glassy slags with respect to their leaching and volume stability. Optical microscopy, X-ray diffraction, scanning electron microscope and a standard test leaching (prEN 12457-2/3) have been used for the investigation. The results show that the disintegrated ladle slag was made volume stable by water granulation, which consisted of 98% glass. However EAF slag 1, EAF slag 2 and the BOF slag formed 17%, 1% and 1% glass, respectively. The leaching test showed that the glass-containing matrix did not prevent leaching of minor elements from the modified slags. The solubility of chromium, molybdenum and vanadium varied in the different modifications, probably due to their presence in different minerals and their different distributions.

  • 19.
    Wang, Zeng
    et al.
    Luleå tekniska universitet.
    Lidström-Larsson, Margareta
    Grahn, Mattias
    Holmgren, Allan
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zeolite coated ATR crystals for new applications in FTIR-ATR spectroscopy2004In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 24, p. 2888-2889Article in journal (Refereed)
  • 20.
    Wang, Zheng
    et al.
    Luleå tekniska universitet.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Sterte, Johan
    Zeolite coated ATR crystal probes2006In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 115, no 2, p. 685-690Article in journal (Refereed)
    Abstract [en]

    Thin and well-defined MFI type molecular sieve films were grown on a range of ATR crystals by employing a seeding method. The type of ATR crystal does not influence film morphology. FTIR spectroscopy was used to evaluate the coated ATR crystals as sensor probes. These novel sensor probes could be used to detect low concentrations of organic molecules in a gas flow.

1 - 20 of 20
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