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  • 1.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Design and Development of Mineral Structure Specific Collectors in Flotation2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The success of mineral flotation processes depends on the hydrophobization of the surface for the desired mineral particles whilst keeping, or making, all other minerals hydrophilic. This is achieved by adding several reagents to the flotation pulp to adsorb selectively at the mineral/water interface. The reagents (surface active agents) which selectively adsorbs on minerals to be floated are called collectors. It is realized that many of these commonly used reagents are highly toxic and often potential threats to the environment. Use of many of theseconventional chemicals will therefore be restricted soon and must eventually be stopped. An immediate effort is necessary to develop alternative eco-friendly reagents in order to continue to extract valuable minerals from ores. In addition, with the steady depletion of high grade, relatively easy to process ores, the mineral industry is confronted with a challenging task of finding more efficient techniques so as to exploit low grade, complex and disseminated typeof ore deposits and old tailing dumps. The development of new selective and environmentally acceptable substances containing almost tailor-made reagents is thus inevitable for sustainability. Several known chelating agents have been appropriately modified to make those behave as selective flotation collectors with some degree of success. The problem is that almost all of the chelating groups form complexes with almost all of the transition and many non-transition metals. As a consequence, absolute selectivity does not exist. Besides beingunsatisfactory from a scientific viewpoint, it assumes that the metal ion specificity observed for a functional group in bulk aqueous system would remain valid during surface chelation at the interface, while in actual practice, the specificity based on metal ion is neither valid nor useful where the cations participating in the complexation reactions are the same, for example separation among the calcium minerals.It is clear that a selective reagent should be based on the reagent interactions not merely with the metal ion on the surface, but with the whole surface. It is more appropriate to design reagents having functional groups so spaced that those are compatible with the relative positions of the metal ion sites available on the surface, that is, to design not just metalspecificbut structure-specific reagents. The understandings of molecular interactions involved in the recognition of surfaces by organic molecules in biomineralization process suggest the possibility of reagents specific to the crystal structure. These understandings have been successfully applied to the rational design and synthesis of molecules either for the control of crystal morphology or to inhibitcrystal growth processes through the recognition of specific crystal surfaces. The idea of molecules consisting of two groups having appropriate spacing between them to achieve structural compatibility during interaction with surface exhibit structure-specificity is of direct relevance to the reagents selectivity in flotation processes. The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying spacing between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant withthe same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite, calcite and fluorite mineral surfaces was studied using Hallimond tube flotation, ζ-potential and FTIR measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much moreselective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ-potential and infrared spectroscopy data. Our investigation revealed that it is possible to design and develop mineral specific reagents in flotation.

  • 2.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Selectivity in Calcium mineral flotation - An analysis of novel an existing approaches2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 3.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Bordes, Romain
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Holmberg, Krister
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Rao, Hanumantha
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Flotation selectivity of novel alkyl dicarboxylate reagents for calcite-fluorite separation2016Ingår i: Tenside Surfactants Detergents, ISSN 0932-3414, E-ISSN 2195-8564, Vol. 53, nr 6, s. 516-523Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of amino acid-based surfactants with a fixed alkyl chain length and with two carboxyl groups separated by a spacer of one, two or three carbon atoms have been synthesized and evaluated as potential collectors for flotation of calcite and fluorite. A monocarboxylate amino acid-based surfactant having the same length of the hydrocarbon tail was also included in the study. Experiments using a Hallimond flotation tube showed that although the flotation reagents solely differs in terms of spacer, their efficacy in terms of flotation recovery varied very much. Whereas on calcite at pH 10.5 only the monocarboxylate collector gave a high yield, on fluorite at the same pH both the monocarboxylate and the dicarboxylate collectors with one carbon between the carboxyl groups gave good results. On calcite at the natural pH the monocarboxylate collector was most efficient but the dicarboxylate collectors with a two- and a three-carbon spacer also gave a reasonable recovery. On fluorite at the natural pH the dicarboxylate collectors with a two- and a three-carbon spacer were most efficient. The potential and the flotation recovery of the mineral particles as afunction of added collector was assessed and the adsorption was also monitored by diffuse reflectance infra-red spectroscopy. Taken together, the results showed that small changes in the head group region of the collector can radically affect flotation recovery. This type of knowledge is important to understand flotation selectivity in a mixture of similar minerals.

  • 4.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Flotation selectivity of novel alkyl dicarboxylate reagents for apatite-calcite separation2015Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 445, s. 40-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The investigation aims to demonstrate the conceptual thoughts behind developing mineral specific reagents for use in flotation of calcium containing ores. For this purpose, a series of dicarboxylate-based surfactants with varying distance between the carboxylate groups (one, two or three methylene groups) was synthesized. A surfactant with the same alkyl chain length but with only one carboxylate group was also synthesized and evaluated. The adsorption behavior of these new reagents on pure apatite and pure calcite surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant at a specific mineral surface and its molecular structure over a range of concentrations and pH values, as well as the region of maximum recovery, was established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues. For example, out of the four compounds synthesized, only the one where the carboxylate groups were separated by a single methylene group floated apatite but not calcite, whereas calcite was efficiently floated with the monocarboxylic reagent, but not with the other reagents synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in the flotation studies was substantiated by ζ potential and infra-red spectroscopy data

  • 5.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Bordes, Romain
    Chalmers University of Technology.
    Holmberg, Krister
    Chalmers University of Technology.
    Molecular recognition mechanisms in biomineralization applied to reagents selectivity in froth flotation2013Konferensbidrag (Övrigt vetenskapligt)
  • 6.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rao, Hanumantha
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Fredriksson, Andreas
    LKAB.
    Molecular recognition in mineral flotation: Selectivity in apatite-calcite system2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying length between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant with the same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite and calcite mineral surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ potential and infra-red spectroscopy data.

  • 7.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Fredriksson, Andreas
    R&D Mineral Processing, LKAB.
    Rao, Hanumantha
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Novel alkyl aminodicarboxylate reagents for mineral specific flotation2016Ingår i: 2016 SME Annual Conference and Expo: The Future for Mining in a Data-Driven World, Phoenix, United States, 21 - 24 February 2016, New York: Society for Mining, Metalurgy and Exploration, 2016, s. 807-810Konferensbidrag (Refereegranskat)
    Abstract [en]

    Separation of different calcium minerals have long been an interesting and challenging problem. In this investigation calcium mineral separation is examined by: microflotation, zeta potential measurement and adsorption, using novel collectors having two functional groups instead of one. In theory, by varying the distance between the functional groups, it could be possible to preferentially target one calcium mineral by matching the spatial distance between the sites on the mineral surface. In this investigation two new surfactants have been tested to estimate their ability to float apatite and/or calcite.Preliminary findings show that an increase in distance between the functional groups favors one mineral over the other, and this might be due to differences in the mineral surface structure.

  • 8.
    Kota, Hanumantha Rao
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vilinska, Annamaria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Chernyshova, IV
    Revisiting sulphide mineral (bio) processing: a few priorities and directions2013Ingår i: Powder Metallurgy & Mining, ISSN 2168-9806, Vol. 2, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large efforts are being made to streamline the conventional (chemical and physical) technological schemes of ore processing, remediation and environmental protection towards reducing overall costs, limiting the use of dangerous substances, decreasing waste streams and improving waste disposal and recycling practice. Hitherto, search for such innovations has been performed mainly empirically and there is an urgent need to shift these technologies to be more innovative and effective. Alternative biotechnological solutions and solutions mimicking natural processes are also being proposed. However, except for bioleaching, practical exploitation of the biotechnological potential in extractive industries and accompanying environmental protection measures remains far from feasibility. Understanding of the fundamental concepts of aquatic chemistry of minerals–selective adsorption and selective redox reactions at mineral– bacteria–solution interfaces, impact innovating conventional and bio-flotation, as well as (bio) remediation/detoxification of mineral and chemical wastes are necessary. Molecular-level knowledge and coherent understanding of minerals contacted with aqueous solutions is required that underlie great opportunities in controlling abiotic and biotic mineral– solution interfaces towards the grand challenge of tomorrow’s science and mineral processing technology

  • 9.
    Kota, Hanumantha Rao
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Javadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Vilinska, Annamaria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Chernyshova, I.V.
    Revisiting sulphide mineral (bio) processing: a few priorities and directions2013Ingår i: XV Balkan Mineral Processing Congress, 12-16 June 2013, Sozopol, Bulgaria, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Large efforts are being made to streamline the conventional (chemical and physical) technological schemes of ore processing, remediation and environmental protection towards reducing overall costs, limiting the use of dangerous substances, decreasing waste streams and improving waste disposal and recycling practice. Hitherto, search for such innovations has been performed mainly empirically and there is an urgent need to shift these technologies to be more innovative and effective. Alternative biotechnological solutions and solutions mimicking natural processes are also being proposed. However, except for bioleaching, practical exploitation of the biotechnological potential in extractive industries and accompanying environmental protection measures remains far from feasibility.Understanding of the fundamental concepts of aquatic chemistry of minerals–selective adsorption and selective redox reactions at mineral–bacteria–solution interfaces, impact innovating conventional and bio-flotation, as well as (bio)remediation/detoxification of mineral and chemical wastes. Molecular-level knowledge and coherent understanding of minerals contacted with aqueous solutions is required that underlie great opportunities in controlling abiotic and biotic mineral–solution interfaces towards the grand challenge of tomorrow’s science and mineral processing technology.

  • 10.
    Patra, Anuttam
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rao, Hanumantha
    Fredriksson, Andreas
    LKAB.
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Design and development of novel mineral-specific collectors for flotation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Almost all of the flotation reagents used today were discovered by continued application of empirical methods and/or trial and error experimentation. Moreover, with the metal-ion specific approach used so far, it is difficult to separate the minerals containing the same constituent metal ion. A critical assessment of molecular recognition processes involved in biomineralization suggested the possibility of using reagents which are surface specific. The concept that the molecules consisting of two or more functional groups having appropriate spacing between those so as to achieve structural/stereochemical compatibility during interaction with the mineral surface exhibit structure-specificity is thought to be extended to the design of specific collectors in flotation processes. In the present study, for the first time, a rational design of surface active molecules, and thereby the recognition of crystal faces (of minerals) by these molecules through structural and stereochemical matching is being utilized successfully to selectively float various minerals. For this purpose, carboxylate-based collectors (for mineral specific flotation of calcium minerals) as well as xanthate-based collectors (for mineral specific flotation of sulphide minerals) with a fixed alkyl chain length but having two functional groups with varying geometrical distances (separated by a spacer of one, two and three carbon atoms) between them have been synthesized. In this article, we have discussed the design, synthesis, purification of these novel mineral specific collectors as well as their important solution parameters in relation to flotation processes.

  • 11.
    Pålsson, Bertil
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Mathew, Aji P.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Nano-entities for surface modification of minerals: Implications for flotation2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Adsorption of nano-entities (nano-cellulose and nano-chitin) on quartz and magnetite was investigated as a function of pH with measurement of Zeta potential as a tool. The results show strong adsorption of the nano-entities on both minerals, leading to charge reversal. However, the adsorption appears to be largely non-preferential over the concentration and pH ranges investigated.

    Micro-flotation results show that both nano-entities float quartz to the same extent, and that the same is true for magnetite. However, the amount floated is higher for quartz. There is also an indication that Chitin at pH 8 has some preference for quartz over magnetite.

    Mini-flotation results for mineral mixtures at pH 8 with Chitin and flotation reagents show that Chitin can selectively float quartz for the given conditions, but the recovery is low. If oleate is added, the selectivity is lost. This means that the nano-entity is probably not a cationic activator, rather it induces some little hydrophobicity to the quartz surface on its own.

  • 12.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Conference in Minerals Engineering Luleå 5 - 6 February 20132013Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 13.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Conference in Minerals Engineering Luleå 7-8 February 20122012Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 14.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Conference in Minerals Engineering 20142014Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 15.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Conference in Minerals Engineering 20152015Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 16.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Conference in Minerals Engineering 20162016Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
1 - 16 av 16
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