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  • 1.
    Abdel-Magied, Ahmed F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Nasser Abdelhamid, Hani
    Ashour, Radwa M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Zou, Xiaodong
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Hierarchical porous zeolitic imidazolate framework nanoparticles for efficient adsorption of rare-earth elements2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 175-184Article in journal (Refereed)
    Abstract [en]

    Hierarchical porous zeolitic imidazolate frameworks nanoparticles (ZIF-8 NPs) were synthesized at room temperature via a template-free approach under dynamic conditions (stirring) using water as a solvent. The ZIF-8 NPs were evaluated as adsorbents for rare earth elements (La3+, Sm3+ and Dy3+). Adsorption equilibrium was reached after 7h and high adsorption capacities were obtained for dysprosium and samarium (430.4 and 281.1 mg g(-1), respectively) and moderate adsorption capacity for lanthanum (28.8 mg g(-1)) at a pH of 7.0. The high adsorption capacitiese, as well as the high stability of ZIF-8 NPs, make the hierarchical ZIF-8 materials as an efficient adsorbent for the recovery of La3+, Sm3+ and Dy3+ from aqueous solution.

  • 2.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Korkmaz, Kivanc
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Dephosphorization and impurity removal from a rare earth phosphate concentrate2017Conference paper (Refereed)
  • 3.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Korkmaz, Kivanc
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Isolation of rare earth element phosphate precipitate in the nitrophosphate process for manufacturing of fertilizer2016In: IMPC 2016 - 28th International Mineral Processing Congress, Canadian Institute of Mining, Metallurgy and Petroleum , 2016Conference paper (Refereed)
    Abstract [en]

    In the present study, the recovery of rare earth elements (REE) in the nitrophosphate process of fertilizer production is investigated. The apatite has been recovered from iron ore tailings by flotation. After digestion of apatite in concentrated nitric acid, Ca(NO3)2.4H2O is first separated by cooling crystallization and then the REEs are recovered by precipitation. Optimum conditions in these steps have been determined in a previous study. The precipitate mainly consists of CaHPO4.2H2O and REE phosphates. In the present study, selective dissolution and re-precipitation have been studied in order to obtain a precipitate that is more concentrated in REEs. The precipitate was selectively dissolved in nitric and phosphoric acid at different acidities (pH 6 to 0) with the liquid /solid ratio of 100 mL/g. It is shown that most of the CaHPO4.2H2O and other calcium containing compounds will be dissolved at pH 2 while the REE phosphates are not dissolved above a pH of approximately 2. Thus, by partial dissolution of the REE precipitate at pH 2.5 most of the solid calcium phosphates will be dissolved and the remaining solid phase, which is more concentrated in REEs, can be filtered off as a fairly concentrated REE solid mass and the liquor can be recycled back to recover more P nutrients. Alternatively, the REE enriched precipitate was dissolved completely in nitric acid and re-precipitated again by addition of ammonium hydroxide to pH 1.2. A chemical equilibrium software, MEDUSA (Puigdomenech, 2013) has been used to evaluate the experimental results and to estimate the optimum conditions for selectively dissolving the precipitate. 

  • 4.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Recovery of phosphorous and rare earth elements from an apatite concentrate2018Conference paper (Refereed)
  • 5.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Korkmaz, Kivanc
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Processing of a rare earth phosphate concentrate obtained in the nitrophosphate process of fertilizer production2019In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 189, article id 105144Article in journal (Refereed)
    Abstract [en]

    In this study, different processes have been developed and applied to treat a rare earth phosphate concentrate obtained within the nitrophosphate process of fertilizer production. Methods to remove impurities such as Fe and Ca have been investigated as well as to separate the phosphorous and thereby facilitate dissolution of the rare earth elements (REE). These methods include thermal treatment with sodium hydroxide and sodium double sulphate precipitation with and without alkaline conversion, followed by selective dissolution in different acids. The proposed processes were compared and analyzed from the perspective of introducing an appropriate intermediate product for further individual REE separation. The results have shown that after thermal treatment with NaOH at 400 °C, the phosphorous can be removed from the rare earth phosphate concentrate by water leaching. Investigation of different REE phosphate concentrates demonstrated that mixed Ca and REE phases, e.g. REEmCan(PO4)3m+2n/3 and CaHPO4 are less likely to dephosphorize than REE(PO4).nH2O and FePO4.H2O under these conditions. The recovery of REE to a mild acidic solution is limited by the presence of remaining phosphate ions and by the formation of REE oxide phases during the thermal treatment. The results also show that a solution containing 40 g/L REE; free of phosphorous, calcium and iron can be obtained after reprecipitation of the rare earth phosphate concentrate as sodium rare earth double sulphates followed by alkaline conversion with sodium hydroxide and dissolution in nitric acid.

  • 6.
    Alemrajabi, Mahmood
    et al.
    KTH.
    Rasmuson, Åke C.
    KTH.
    Korkmaz, Kivanc
    Forsberg, Kerstin
    KTH.
    Processing of a rare earth phosphate concentrate obtained inthe nitrophosphate process of fertilizer productionManuscript (preprint) (Other academic)
  • 7.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Korkmaz, Kivanc
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Recovery of rare earth elements from nitrophosphoric acid solutions2017In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 169, p. 253-262Article in journal (Refereed)
    Abstract [en]

    In the present study, the recovery of rare earth elements (REEs) from an apatite concentrate in the nitrophosphate process of fertilizer production has been studied. The apatite concentrate has been recovered from iron ore tailings in Sweden by flotation. In the first step, the apatite is digested in concentrated nitric acid, after which Ca(NO3)2.4H2O is separated by cooling crystallization. The solution is then neutralized using ammonia whereby the REEs precipitate mainly as phosphates (REEPO4.nH2O) and together with calcium as REEn Cam (PO4)(3n + 2m) / 3. In this work, the degree of rare earth coprecipitation during seeded cooling crystallization of Ca(NO3)2.4H2O has been studied. The solubility of calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) in acidic nitrophosphoric acid solutions in the temperature range of − 2 °C to 20 °C has been determined. For the neutralization step, it is shown that the calcium concentration and the final pH play an important role in determining the concentration of REEs in the precipitate. It is found that reaching maximum recovery of REE with minimum simultaneous precipitation of calcium requires careful control of the final pH to about 1.8. It is further observed that the precipitation yield of REEs and iron is favored by a longer residence time and higher temperature. Finally, the effect of seeding with synthesized REE phosphate crystals as well as a mixture of REE and Ca phosphates on the precipitation rate and the composition of the precipitate was studied.

  • 8.
    Alemrajabi, Mahmood
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Korkmaz, Kivanc
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Upgrading of a rare earth phosphate concentrate within the nitrophosphate process2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 198, p. 551-563Article in journal (Refereed)
    Abstract [en]

    In the nitrophosphate process of fertilizer production, rare earth elements (REE) can be recovered as a REE phosphate concentrate. In this process, after digestion of apatite in concentrated nitric acid, Ca(NO3)2.4H2O is first separated by cooling crystallization and then the REE are precipitated in phosphate form by a partial neutralization step using ammonia. The obtained REE phosphate concentrate is contaminated by mainly calcium and iron, and the main solid phases are CaHPO4.2H2O, FePO4.2H2O and REEPO4.nH2O.

    In this study, a process to obtain a concentrate more enriched with REE with low concentration of calcium and iron and free of phosphorous is developed. In the developed process, enrichment and dephosphorization of the rare earth phosphate concentrate has been achieved by selective dissolution and re-precipitation of the REE as a sodium REE double sulfate salt. It is shown that by selective dissolution of the REE concentrate in nitric acid at a pH of 2.4, most of the calcium and phosphorus are dissolved, and a solid phase more enriched in REE is obtained. Thereafter, the REE phosphate concentrate is first dissolved in a mixture of sulfuric-phosphoric acid and then the REE are reprecipitated as NaREE(SO4)2.H2O by addition of a sodium salt. More than 95% of the Ca, Fe and P are removed and a REE concentrate containing almost 30 mass% total REE is obtained.

  • 9.
    Alemrajabi, Mahmoud
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Recovery of REE from an apatite concentrate in the nitrophosphate process of fertilizer production.2015Conference paper (Refereed)
  • 10.
    Ashour, Radwa
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Nuclear Materials Authority, P.O. Box 530, 11381 El Maadi, Cairo, Egypt.
    Samouhos, Michail
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Polido Legaria, Elizabeth
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Svärd, Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Högblom, Joakim
    AkzoNobel, Pulp and Performance Chemicals AB.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Palmlöf, Magnus
    Kessler, Vadim G.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Seisenbaeva, Gulaim A.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    DTPA-Functionalized Silica Nano- and Microparticles for Adsorption and Chromatographic Separation of Rare Earth Elements2018In: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 6, no 5, p. 6889-6900Article in journal (Refereed)
    Abstract [en]

    Silica nanoparticles and porous microparticles have been successfully functionalized with a monolayer of DTPA-derived ligands. The ligand grafting is chemically robust and does not appreciably influence the morphology or the structure of the material. The produced particles exhibit quick kinetics and high capacity for REE adsorption. The feasibility of using the DTPA-functionalized microparticles for chromatographic separation of rare earth elements has been investigated for different sample concentrations, elution modes, eluent concentrations, eluent flow rates, and column temperatures. Good separation of the La(III), Ce(III), Pr(III), Nd(III), and Dy(III) ions was achieved using HNO3 as eluent using a linear concentration gradient from 0 to 0.15 M over 55 min. The long-term performance of the functionalized column has been verified, with very little deterioration recorded over more than 50 experiments. The results of this study demonstrate the potential for using DTPA-functionalized silica particles in a chromatographic process for separating these valuable elements from waste sources, as an environmentally preferable alternative to standard solvent-intensive processes.

  • 11.
    Chen, Song
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Abdel-Magied, Ahmed F.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Fu, Le
    Uppsala Universitet, Department of Engineering Sciences.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Incorporation of strontium and europium in crystals of α-calcium isosaccharinate2019In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 364, p. 309-316Article in journal (Refereed)
    Abstract [en]

    The final repository for short-lived, low and intermediate level radioactive waste in Sweden is built to act as a passive repository. Already within a few years after closure water will penetrate the repository and conditions of high alkalinity (pH 10.5―13.5) and low temperature (< 7 °C) will prevail. The mobility of radionuclides in the repository is dependent on the radionuclides distribution between solid and liquid phases. In the present work the incorporation of strontium (II) and europium (III) in α-calcium isosaccharinate (ISA) under alkaline conditions (pH ~10) at 5 °C and 50 °C have been studied. The results show that strontium and europium are incorporated into α-Ca(ISA)2 when crystallized both at 5 °C and 50 °C. Europium is incorporated to a greater extent than strontium. The highest incorporation of europium and strontium at 5 °C rendered the phase compositions Ca0.986Eu0.014(ISA)2 (2.4% of Eu(ISA)3 by mass) and Ca0.98Sr0.02(ISA)2 (2.2% of Sr(ISA)2 by mass). XPS spectra show that both trivalent and divalent Eu coexist in the Eu incorporated samples. Strontium ions were found to retard the elongated growth of the Ca(ISA)2crystals. The incorporation of Sr2+ and Eu3+ into the solid phase of Ca(ISA)2 is expected to contribute to a decreased mobility of these ions in the repository.

  • 12.
    Chen, Song
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Wang, Shihuai
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Li, Hu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap..
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Eu3+ doped monetite and its use as fluorescent agent for dental restorations2018In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 44, no 9, p. 10510-10516Article in journal (Refereed)
    Abstract [en]

    It is essential but challenging to distinguish the dental restorations from the surrounding teeth when removing filling materials from cavity. In this study, Eu3+ doped monetite was proposed as a fluorescent agent for dental restorations to meet this challenge. Eu3+ doped monetite with enhanced fluorescent property was obtained via a precipitation method. The presence of Eu3+ could prevent the phase transformation of brushite to monetite. However, all the brushite particles transformed to monetite at 300 °C and to tricalcium phosphate at 800 °C. The emission intensity increased with the addition of Eu3+ and reached the maximum when 12 mol% Eu3+ was added into the aqueous solution. With either 254 nm or 393 nm excitation, Eu3+ doped monetite showed the strongest fluorescence emission peaking at 616 nm and other two moderate bands peaking at 699 nm and 593 nm. The excitation spectra at the emission wavelength of 616 nm showed strong absorption peaks at 254 nm and 393 nm. We further investigate the fluorescence properties of Eu3+ doped monetite in one type of dental restorations. Glass ionomer cement with Eu3+ doped monetite exhibited clear fluoresce with origin color under UV irradiation at 254 nm, showing that Eu3+doped monetite is a promising fluorescent agent for dental restorations.

  • 13.
    Chernyshev, Alexander
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Impact of organic cement additives on the mobility of radionuclides in a radioactive waste repository2017Conference paper (Refereed)
  • 14.
    Chernyshev, Alexander N.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories2018In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 95, p. 172-181Article in journal (Refereed)
    Abstract [en]

    Superplasticizers are important additives used in concrete barriers in geological waste repositories. Superplasticizers have been a major concern in the long-term assessments of safe geological disposal for radioactive waste since superplasticizers and their degradation products can act as complexing ligands and thereby increase the mobility of radionuclides. In this work a new type of superplasticizer, based on a polyaryl ether polymer, has been characterized. It was found that the superplasticizer combines the structural features of polycarboxylate ether based superplasticizers and sulfonated naphthalene-formaldehyde based superplasticizers and that it contains organophosphatecharged groups. A novel method for evaluating the rate of degradation of the superplasticizer under alkaline conditions was elaborated and the degradation products and rate constant of the process was determined. The results demonstrate that degradation occurs rapidly compared to the typical lifetime of a repository.

  • 15.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of Metal Fluoride Hydrates from Mixed Acid Solutions2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this work crystal growth and nucleation of b-FeF3×3H2O and crystallization of chromium (III), iron (III) and nickel (II) fluoride hydrates from mixed acid (1-3 mol/kg HNO3 and 1-6 mol/kg free HF) have been investigated.

    The solubility of b-FeF3×3H2O has been determined in solutions of different hydrofluoric acid (1-7mol/ kg) and nitric acid (0-7mol/ kg) concentrations at 30, 40 and 50°C. The total iron concentration at equilibrium ranges from about 1 to 35 g/kg solution. In the range of investigated conditions the solubility in terms of total iron content increases with increasing temperature and decreases with increasing concentration of hydrofluoric acid and nitric acid. The results are analysed by examining the chemical speciation in the solutions.

    The crystal growth kinetics of b-FeF3×3H2O crystals have been studied by performing seeded isothermal desupersaturation experiments in solutions of 1.5-3.0 mol/ kg nitric acid and 1.4- 5.6 mol/ kg free hydrofluoric acid at 30, 40 and 50°C. The results show that the crystal growth is surface integration controlled. When the driving force is based on a proper speciation no clear correlation of the growth rate with hydrofluoric acid or nitric acid concentration is found. The rate is about the same in industrial pickle liquor as in pure acid solutions. The growth rate at a supersaturation ratio (c(FeF3)free/cs(FeF3)free) of 2 was found to be 5.2×10-12m/s at 30°C, 7.9×10-12m/s at 40°C and 20×10-12m/s at 50°C. Thus, the crystal growth rate at 50°C is about four times higher than at 30°C. The temperature dependence of the rate constant corresponds to an activation energy of 55kJ/ mol.

    Crystallization from solutions supersaturated with both Cr(III) and Fe(III) has been investigated and it has been observed that Fe(III) and Cr(III) crystallizes in the form of Cr(Fe)F3×3H2O which is isostructural with CrF3×3H2O. Iron(III) and nickel(II) crystallizes into an unidentified fluoride hydrate crystal.

    The crystal growth rate of CrF3×3H2O at 50°C is about the same as the growth rate of b-FeF3×3H2O crystals.

  • 16.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Valorisation of phosphate rock by hydrometallurgical processing2017In: 16ème Congrès de la Société Française de Génie des Procédés SFGP (16th Congress of the French Chemical Engineering Society), 2017Conference paper (Refereed)
  • 17.
    Forsberg, Kerstin M.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mohammadi, M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ghafarnejad Parto, S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Martínez de la Cruz, Joaquin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Fredriksson, A.
    LKAB.
    Recovery of REE from an apatite concentrate2014Conference paper (Refereed)
  • 18.
    Forsberg, Kerstin M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    The influence of hydrofluoric acid and nitric acid on the growth kinetics of iron(III) fluoride trihydrate2015In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 423, p. 16-21Article in journal (Refereed)
    Abstract [en]

    The influence of hydrofluoric acid and nitric acid concentration on the growth rate of beta-FeF3 center dot 3H(2)O crystals has been studied in different hydrofluoric acid (4.7-10.7 mol/(kg H2O)) and nitric acid (2.1-4.6 mol/(kg H2O)) mixtures at 50 degrees C. Seeded desupersaturation experiments were performed and the results were evaluated by considering the chemical speciation using two different speciation programs. The growth rate at 50 degrees C at a supersaturation ratio of 2, expressed in terms of free FeF3, was found to be in the range of (0.4-3.8) x 10(-11) m/s. The growth rate order was found to be two or higher in all experiments. The low growth rate and high growth rate order indicate that the growth rate is governed by the surface integration step. The growth rate was found to be independent of variations in acid concentrations: this is in accordance with the assumption of a surface integration controlled growth rate.

  • 19.
    Forsberg, Kerstin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Mohammadi, M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Ghafarnejad Parto, S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Alemrajabi, Mahmoud
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Korkmaz, Kivanc
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Martínez De La Cruz, Joaquin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Novel hydrometallurgical methods for recovery and separation of REE2014Conference paper (Refereed)
  • 20.
    Forsberg, Kerstin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Nénert, G.
    Malvern Panalytical.
    Martineau, C.
    Institut Lavoisier de Versailles.
    Tao, T.
    University of Houston.
    Halasyamani, Shiv
    University of Houston.
    Crystal structure of hydrated fluorides M F 2 ·4H 2 O ( M = Zn, Ni, Co): a combined approach2015Conference paper (Refereed)
  • 21.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystal growth of iron(III) flouride trihydrate in mixed acidManuscript (preprint) (Other academic)
  • 22.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization in hydrofluoric acid and nitric acid solutions containing iron(III), chronium(III) and nickel(II).Manuscript (preprint) (Other academic)
  • 23.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of metal fluoride hydrates from mixed hydrofluoric and nitric acid solutions, Part I: Iron (III) and Chromium (III)2010In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 312, no 16-17, p. 2351-2357Article in journal (Refereed)
    Abstract [en]

    Crystallization from hydrofluoric acid/nitric acid solutions supersaturated with Fe(III) and Cr(III) has been investigated. Iron and chromium crystallizes into a solid solution in the form of Cr(Fe)F-3 center dot 3H(2)O, which is isostructural with CrF3 center dot 3H(2)O and alpha-FeF3 center dot 3H(2)O. By seeded isothermal desupersaturation experiments, the growth rate of beta-FeF3 center dot 3H(2)O crystals at 50 degrees C has been studied in hydrofluoric acid and nitric acid solutions containing Cr(III). It is found that the growth rate of beta-FeF3 center dot 3H(2)O is essentially uninfluenced by the presence of 5 g/kg Cr(III). At 50 degrees C and a supersaturation ratio of 2 (c(FeF3)(free)/c(s)(FeF3)(free)), the growth rate is (0.8-2.2) x 10(-11) m/s in 3 mol/(kg solution) HFfree and 3 mol/(kg solution) HNO3.

  • 24.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of metal fluoride hydrates from mixed hydrofluoric and nitric acid solutions, part II: Iron (III) and nickel (II)2010In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 312, no 16-17, p. 2358-2362Article in journal (Refereed)
    Abstract [en]

    Crystallization of nickel fluoride hydrate from mixed pickle acid and the influence of Ni(II) on growth rate of beta-FeF3 center dot 3H(2)O have been studied. Iron and nickel crystallize into an unidentified Fe/Ni fluoride hydrate crystal having the overall mol ratio of Ni, Fe, and F equal to 1:2:8, which is in accordance with the number of fluoride ions needed to balance the positive charges of Ni and Fe. The most probable empirical formula of this material is (FeF3)(2)NiF2(H2O)(6-10). By seeded isothermal desupersaturation experiments, growth rate of beta-FeF3 center dot 3H(2)O crystals at 50 degrees C has been studied in a hydrofluoric acid and nitric acid solution containing Ni(II). It is found that the growth rate of beta-FeF3 center dot 3H(2)O is essentially uninfluenced by the presence of 4 g/kg Ni(II).

  • 25.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystal growth kinetics of iron fluoride trihydrate2006In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 296, no 2, p. 213-220Article in journal (Refereed)
    Abstract [en]

    Crystal growth of beta-FeF3 • 3H(2)O has been investigated in mixtures of 3 mol kg(-1) hydrofluoric acid and 3 mol kg(-1) nitric acid at 30, 40 and 50 degrees C. Seeded isothermal desupersaturation experiments have been performed in the range: 1.3 < S < 3.6. Solution samples were analysed for total iron concentration with inductively coupled plasma atomic emission spectroscopy. The true supersaturation driving force was estimated by a proper speciation using the software SSPEC using appropriate stability constants. Growth rate parameters of the BCF surface diffusion growth rate equation and the empirical power-law equation have been estimated by fitting the supersaturation balance equation using a nonlinear optimization procedure. The results show that the growth rate is surface integration controlled. The growth rate at a supersaturation ratio of 2 was found to be 3.5 x 10(-12) m s(-1) at 30 degrees C, 7.4 x 10(-12) m s(-1) at 40 degrees C and 16 x 10(-12) m s(-1) at 50 degrees C. The activation energy of the rate constant of crystal growth was found to be 61 kJ mol(-1). .

  • 26.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Recycling of waste pickle acid by precipitation of metal fluoride hydrates2007In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 20, no 9, p. 950-955Article in journal (Refereed)
    Abstract [en]

    Stainless steel is pickled in mixed acid solutions (1-3 M HNO3 and 0.5-4 M HF). The spent solution is usually neutralized with lime, and in Sweden about 18,000 tons/yr of metal hydroxide sludge is disposed as landfill waste. We are developing a cost-saving and environmentally friendly process, involving crystallization of beta-FeF3 . 3H(2)O, where the metal content is recovered and the acid is recycled. Iron has been successfully separated from spent pickle bath solutions by precipitation of beta-FeF3 . 3H(2)O in a continuous crystallizer (10 L scale) where the solution is concentrated by nanofiltration. The crystal growth rate of beta-FeF3 . 3H(2)O has been determined in industrial pickle bath solutions at 50 degrees C and the results have been compared to previous measurements in pure HF/HNO3 solutions prepared in the laboratory. The growth rate of beta-beta eF(3) . 3H(2)O crystals at 50 degrees C is in the order of 10(-11) m/s in both industrial and pure acid mixtures.

  • 27.
    Forsberg, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Precipitation from HF and HNO3 solutions containing iron (III), nickel (II) and chromium (III)2008In: Proc. 17’th International Symposium on Industrial Crystallization / [ed] JP Janssens; J Ulrich, 2008, p. 1175-1180Conference paper (Refereed)
  • 28.
    Forsberg, Kerstin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Rodríguez Varela, Raquel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Martínez, Joaquin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Kloo, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Processing of a rare earth element concentrate by hollow fibre supported liquid membrane extraction2017Conference paper (Refereed)
  • 29.
    Hammer-Olsson, Roy
    et al.
    Perstorp AB.
    Jansson, Inger
    Perstorp AB.
    Hultén, Felix
    Perstorp AB.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Method of purifying potassium hydroxide2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Method of purifying potassium hydroxide comprising (a) providing a solution of saturated potassium hydroxide solution having a temperature in the range from about -25 to about 60 0C (b) controling the temperature of the solution in such a way that the variation in temperature is in a range from about 0 to about 5 °C/h to form crystals of potassium hydroxide (c) separating the crystals from the solution.

  • 30.
    Kaya, Şerif
    et al.
    Middle East Technical University.
    Peters, Edward Michael
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Dittrich, Carsten
    MEAB Chemie Technik GmbH.
    Stopic, Srecko
    RWTH Aachen University.
    Friedrich, Bernd
    RWTH Aachen University.
    Scandium Recovery from an Ammonium Fluoride Strip Liquor by Anti-Solvent Crystallization2018In: Metals, ISSN 2075-4701, Vol. 8, no 10Article in journal (Refereed)
    Abstract [en]

    In this study, the crystallization of scandium from ammonium fluoride strip liquor, obtained by solvent extraction, was investigated using an anti-solvent crystallization technique. Acetone, ethanol, methanol and isopropanol were added individually to the strip liquor as the anti-solvent and scandium was precipitated and obtained in the form of (NH4)3ScF6 crystals. The results show that scandium can be effectively crystallized from the strip liquor to obtain an intermediate, marketable scandium product. Yields greater than 98% were obtained using an anti-solvent to strip liquor volumetric ratio of 0.8. Acetone had the least performance at lower anti-solvent to strip liquor volumetric ratios, possibly due to its limited H bonding capability with water molecules when compared to alcohols.

  • 31.
    Korkmaz, Kivanc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Alemrajabi, Mahmood
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Recovery of rare earth elements from spent NiMH HEV batteries via selective roasting and water leaching2017Conference paper (Refereed)
  • 32.
    Korkmaz, Kivanc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Alemrajabi, Mahmood
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Transport Phenomena.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Recoveries of Valuable Metals from Spent Nickel Metal Hydride Vehicle Batteries via Sulfation, Selective Roasting, and Water Leaching2018In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 4, no 3, p. 313-325Article in journal (Refereed)
    Abstract [en]

    The recoveries of rare earth elements (REEs), nickel, and cobalt from hybrid electric vehicle batteries by sulfation, selective roasting, and water leaching have been studied. The cathode and anode materials of a Panasonic Prismatic Module nickel metal hydride (NiMH) battery were used in the study. The optimal conditions for each step of the process were determined by performing lab-scale experiments. It was found that 8 mol/L of sulfuric acid was sufficient for the sulfation with a solid-to-liquid ratio of 1/5. The optimal roasting conditions was determined to be 850 °C for 2 h. Under optimal conditions, 96% of the REEs could be obtained in the aqueous phase with negligible contamination of Ni and Co. The Ni and Co remained in solid phase as oxides together with traces of aluminum, zinc, and iron oxides. This method provides a way for the separation of the REEs from nickel, cobalt, and other elements present in the NiMH battery, into a leachate suitable for further processing.

  • 33.
    Korkmaz, Kivanc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Alemrajabi, Mahmood
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Separation of Valuable Elements from NiMH Battery Leach Liquor via Antisolvent Precipitation2020In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 234, article id 115812Article in journal (Refereed)
    Abstract [en]

    Rare earth elements (REE) have been selectively recovered from NiMH battery leach liquors by antisolvent precipitation. The active anode material was leached using sulfuric acid. The REE were then separated from the other elements by precipitation as sulfates after addition of either ethanol or 2-propanol (antisolvent). In a second step, Ni and Co are separated as sulfates by the same technique. The concentration of elements in different acid alcohol mixtures at 25 degrees C and -10 degrees C respectively are presented as a function of time after addition of the alcohol, and the optimum conditions for separation of the REE in pure form are presented. Under optimum conditions, 5.6 mol/L (Organic/Aqueous (O/A) volumetric ratio = 0.7) of 2-propanol at 25 degrees C, 82% of the REE have precipitated 3 h after addition of the antisolvent and the purity is 99.9%.

  • 34.
    Korkmaz, Kivanc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Alemrajabi, Mahmood
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Sustainable Hydrometallurgical Recovery of Valuable Elements from Spent Nickel-Metal Hydride HEV Batteries2018In: Metals, ISSN 2075-4701, Vol. 8, no 12Article in journal (Refereed)
    Abstract [en]

    In the present study, the recovery of valuable metals from a Panasonic Prismatic Module 6.5 Ah NiMH 7.2 V plastic casing hybrid electric vehicle (HEV) battery has been investigated, processing the anode and cathode electrodes separately. The study focuses on the recovery of the most valuable compounds, i.e., nickel, cobalt and rare earth elements (REE). Most of the REE (La, Ce, Nd, Pr and Y) were found in the anode active material (33% by mass), whereas only a small amount of Y was found in the cathode material. The electrodes were leached in sulfuric acid and in hydrochloric acid, respectively, under different conditions. The results indicated that the dissolution kinetics of nickel could be slow as a result of slow dissolution kinetics of nickel oxide. At leaching in sulfuric acid, light rare earths were found to reprecipitate increasingly with increasing temperature and sulfuric acid concentration. Following the leaching, the separation of REE from the sulfuric acid leach liquor by precipitation as NaREE (SO4)(2)center dot H2O and from the hydrochloric acid leach solution as REE2 (C2O4)(3)center dot xH(2)O were investigated. By adding sodium ions, the REE could be precipitated as NaREE (SO4)2 center dot H2O with little loss of Co and Ni. By using a stoichiometric oxalic acid excess of 300%, the REE could be precipitated as oxalates while avoiding nickel and cobalt co-precipitation. By using nanofiltration it was possible to recover hydrochloric acid after leaching the anode material.

  • 35.
    Korkmaz, Kivanc
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Hydrometallurgical process development for recycling of spent NiMH battery systems from the transport sector2016Conference paper (Refereed)
  • 36.
    Larsson, M
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Yan, J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Liu, Longcheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Storm water issues in biomass-fired combined heat and power plants2015Conference paper (Refereed)
  • 37.
    Larsson, Magnus
    et al.
    KTH.
    Yan, Jinying
    KTH. Vattenfall AB, Sweden.
    Nordenskjöld, C.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Characterisation of stormwater in biomass-fired combined heat and power plants: Impact of biomass fuel storage2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 170, p. 116-129Article in journal (Refereed)
    Abstract [en]

    Characteristics of stormwater in industrial areas are evaluated, specifically based on a biomass-fired combined heat and power (CHP) plant with on-site biomass fuel storage. An evaluation method is developed to combine general methodology applied for stormwater characterisation with the on-site features of the biomass-fired CHP plant. Investigations were carried out through on-site monitoring and laboratory experiments with the defined methodology. Recycled wood chips as biomass fuel currently used in Swedish biomass-fired CHP plants have been used as an example for this study. The impacts of outdoor biomass fuel storage have been analysed for both runoff water quantity and quality. The results indicate that the properties of stored biomass fuels will significantly affect the runoff quantity by its water absorption capability. The overall runoff quality is highly depended on precipitation intensity and the runoff volume from the biomass storage piles, which is influenced by the water retention capacity and leaching ability of biomass fuels. The practical data and information presented in this paper can be used to understand the principal issues and the most important factors for internal control of contamination sources in order to achieve sustainable Energy-Water systems for bioenergy conversion in biomass-fired CHP plants.

  • 38.
    Martinez, Joaquin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rodriguez Varela, Raquel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Factors Influencing Separation Selectivity of Rare Earth Elements in Flat Sheet Supported Liquid Membranes2018In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 191, p. 134-155Article in journal (Refereed)
    Abstract [en]

    Separation selectivity of the mixture Yttrium-Neodymium-Dysprosium using Bis (2-ethylhexyl) hydrogen phosphate (D2EHPA) as extractant in a flat sheet supported liquid membrane was studied by simulations. A new definition of selectivity and a diffusional-kinetic transient model were used in the calculations. Resistance distribution between the phases, stripping phase pH, extractant concentration and initial feed concentration have great influence on selectivity and process time and their appropriate management would improve separation. The analysis of selectivity using the present model would be a useful tool to design a multistage process aimed at the separation of a multicomponent mixture of rare earth elements into its constituents.

  • 39.
    Mohammadi, Maryam
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    De La Cruz, Joaquin Martinez
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rasmuson, Åke
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Separation of Nd(III), Dy(III) and Y(III) by solvent extraction using D2EHPA and EHEHPA2015In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 156, p. 215-224Article in journal (Refereed)
    Abstract [en]

    The equilibrium separation of trivalent rare earth elements (Nd(III), Dy(III), and Y(III)) from hydrochloric acid solution by di-(2-ethylhexyl) phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethyl hexyl ester (EHEHPA) separately and in mixtures has been studied. The effect of extractant concentration, extractant mixture composition and solution acidity has been investigated. The results show that a mixture of D2EHPA and EHEHPA provide a better separation of Y(III) from Dy(III) when the total extractant concentration is 0.06 and 0.09 mol/L, while the separation is better using pure EHEHPA at higher extractant concentration (0.15 mol/L). The separation of Nd(III) from Y(III) and Dy(III) is higher using pure D2EHPA (0.06 and 0.15 mol/L). The results show that for the complexation of the Nd(III) ions approx. 1-2 hydrogen ions/rare earth element (REE) ion are released to the aqueous phase upon binding approximately 1 extractant dimer on average. For the complexation of Y(III) and Dy(III) ions 2-3 hydrogen ions are released upon binding approximately two extractant dimers on average. Accordingly, under the conditions of this work the complexation involves not only extractant molecule dimers but also monomers or aggregated REE species to some extent, and a fraction of the REE is extracted as chloride complexes. (C) 2015 Elsevier B.V. All rights reserved.

  • 40. Nenert, Gwilherm
    et al.
    Fabelo, Oscar
    Forsberg, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Colin, Claire V.
    Rodriguez-Carvajal, Juan
    Structural and magnetic properties of the low-dimensional fluoride beta-FeF3(H2O)(2)center dot H2O2015In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 44, no 31, p. 14130-14138Article in journal (Refereed)
    Abstract [en]

    We have reinvestigated the crystal structure of the low-dimensional fluoride beta-FeF3(H2O)(2)center dot H2O using high resolution neutron and X-ray diffraction data. Moreover we have studied the magnetic behavior of this material combining medium resolution and high flux neutron powder diffraction together with magnetic susceptibility measurements. This fluoride compound exhibits vertex-shared 1D Fe3+ octahedral chains, which are extended along the c-axis. The magnetic interactions between adjacent chains involve super-superexchange interactions via an extensive network of hydrogen bonds. This interchain hydrogen bonding scheme is sufficiently strong to induce a long range magnetic order appearing below T = 20(1) K. The magnetic order is characterized by the propagation vector k = (0, 0, 1/2), giving rise to a strictly antiferromagnetic structure where the Fe3+ spins are lying within the ab-plane. Magnetic exchange couplings extracted from magnetization measurements are found to be J(II)/k(b) = -18 K and J(perpendicular to)/k(b) = -3 K. These values are in good agreement with the neutron diffraction data, which show that the system became anti-ferromagnetically ordered at ca. T-N = 20(1) K.

  • 41.
    Nénert, G.
    et al.
    Malvern Panalytical.
    Fabelo, O.
    Institut Laue-Langevin.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Colin, C. V.
    Université Grenoble Alpes.
    Rodríguez-Carvajal, J.
    Institut Laue-Langevin.
    Structural and magnetic properties of the low dimensional fluoride β-FeF3.3H2O2015Conference paper (Refereed)
  • 42.
    Peters, Edward
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Dittrich, C.
    MEAB Chemie Technik GmbH.
    Kaya, S.
    MEAB Chemie Technik GmbH.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Crystallization of a pure scandium phase from solvent extraction strip liquors2018Conference paper (Refereed)
  • 43.
    Peters, Edward
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Kaya, S.
    Dittrich, C.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Recovery of scandium by crystallization techniques2018Conference paper (Refereed)
    Abstract [en]

    Bauxite residues, so called red mud, can be processed to recover various valuable end products, whilst reducing the environmental impact of the waste. Scandium is one of the valuable elements in bauxite residues. It is possible to extract and enrich scandium from red mud by leaching and solvent extraction. Scandium can then be recovered from the pregnant strip liquor by crystallisation. Different crystallisation techniques can be used to generate the supersaturation required for scandium to crystallise out as a salt. In the present work, the crystallisation of an ammonium scandium fluoride phase by cooling and anti-solvent crystallisation techniques is presented with respect to crystal quality (purity, size and morphology) and yield. 

  • 44.
    Peters, Edward Michael
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Kaya, Şerif
    Middle East Technical University, Mining Engineering Department, Ankara, Turkey.
    Dittrich, Carsten
    MEAB Chemie Technik GmbH, Aachen, Germany.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Recovery of scandium by crystallization techniques2019In: Journal of Sustainable Metallurgy, ISSN 2199-3823, Vol. 5, no 1, p. 48-56Article in journal (Refereed)
    Abstract [en]

    Bauxite residues, i.e., red mud, can be processed to recover various valuable end products, while reducing the environmental impact of the waste. Scandium is one of the valuable elements in bauxite residues. It is possible to extract and enrich scandium from red mud by leaching and solvent extraction. Scandium can then be recovered from the pregnant strip liquor by crystallization. Different crystallization techniques can be used to generate the supersaturation required for scandium to crystallize out as a salt. In the present study, the crystallization of an ammonium scandium fluoride phase by cooling and antisolvent crystallization techniques is presented. Cooling crystallization gave a low yield of ammonium scandium hexafluoride, (NH4)3ScF6, below 50% at the lowest temperature of 1 °C investigated. Antisolvent crystallization using ethanol gave almost complete recovery with precipitation efficiency greater than 98% for an ethanol-to-strip liquor volumetric ratio of 0.8. Solubility data of (NH4)3ScF6 under different temperatures and in different ethanol–strip liquor mixtures is herein presented. The product obtained by antisolvent crystallization had very minute crystals (< 2 µm) due to the high supersaturation generated upon adding ethanol to the strip liquor, while it was easier to obtain larger crystals by cooling crystallization. Fe and Ti impurities were detected in the solid product, and an insight into the mechanism of impurity uptake is discussed.

  • 45.
    Rodríguez Varela, Raquel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Martínez de la Cruz, Joaquín
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Evaluation of Liquid Membrane Systems for REE Extraction2016Conference paper (Refereed)
    Abstract [en]

    Separation and purification of rare earth elements (REE) is of great importance due to the varietyof their technological applications. In this context, liquid membrane separation stand out as an alternative to traditional techniques in order to selectively separate and concentrate REE. Some of the most significant advantages of the liquid membrane technologies are the minimum liquid membrane inventory and the low power consumption (V. S. Kislik 2010). However, membrane instability can be a significant problem for industrial application and the mechanisms behind membrane instability are poorly understood.This study analyses the separation of rare earth elements by means of liquid membranes with the final objective of recovering REE from an apatite concentrate (M. Alemrajabi, 2015, M.Mohammadi, 2015). In this study, the feed phase will consist of an aqueous phase containing REE, the membrane phase will contain organic solvent and carrier (mainly D2EHPA and EHEHPA), and the stripping phase will be a hydrochloric acid solution. In order to analyse the suitability of liquid membranes in the extraction ofREE, a deeper insight into the mechanisms causing instability is needed. In this study, surface tension is considered as the key factor of Marangoni instabilities and spontaneous emulsification (A. M. Neplenbroek 1992. H-D. Zheng 2009, F. F. Zha 1995). The influence of capillary forces and the effect of mass transfer through the membrane will be examined. Furthermore, a comprehensive evaluation of mass fluxes, separation efficiency and membrane performance on a wide range of operating conditions will be conducted in order to optimise the separation process. This study is expected to provide valuable information for the design of more stable and efficient liquid membrane processes.

  • 46.
    Rodríguez Varela, Raquel
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Martínez, J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Rasmuson, Åke C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Comparative performance of emulsion pertraction technology (EPT) and hollow fibre renewal liquid membrane (HFRLM) for REE extraction2017Conference paper (Refereed)
  • 47.
    Österdahl, Kerstin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of iron fluoride trihydrate from mixed acid solutions2005Licentiate thesis, comprehensive summary (Other scientific)
  • 48.
    Österdahl, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Crystallization of beta-FEF3.3H2O in mixtures of nitric and hydrofluoric acid2005In: VDI-Berichte 1901, V D I Verlag GmbH , 2005, p. 17-22Conference paper (Refereed)
    Abstract [en]

    The solubility of β-heh 3·3H 2U has been measured in solutions with a range of different hydrofluoric acid concentrations (2, 4 and 6 mol/kg) and constant nitric acid concentration (3 mol/kg) in order to calculate a solubility constant applicable at the present ionic strength and temperature. Crystal growth of β-FeF 3·3H 2O has been measured in 3molal hydrofluoric acid and 3molal nitric acid solutions at 50°C by performing seeded isothermal desupersaturation experiments (1 < S < 3). The supersaturation was recorded by taking out solution samples which were analysed for total iron concentration with inductively coupled plasma atomic emission spectrometry (ICP-AES). The true supersaturation driving force was estimated by a proper speciation to account for the complexation, using the software SSPEC and relevant stability constants. Parameters of a desired growth rate equation were estimated by fitting the supersaturation balance equation directly to the supersaturation measurements. The results show that growth of β-FeF 3·3H 2O follows a parabolic rate law (g= 2,0 ±0,2). The growth rate at S= 2 was found to be 4,6×10- 11 m/s (50°C). The growth order and the low value of the growth rate suggest that the rate is surface integration controlled.

  • 49.
    Österdahl, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke C
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Solubility of beta-FeF3 center dot 3H(2)O in mixtures of nitric and hydrofluoric acid2006In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 51, no 1, p. 223-229Article in journal (Refereed)
    Abstract [en]

    The solubility of beta-FeF(3) center dot 3H(2)O has been measured in solutions with different concentrations of nitric acid (0 to 7 in) and hydrofluoric acid (1 to 6 m) at the temperatures of (30, 40, and 50) degrees C. The total iron concentration at equilibrium was measured with inductively coupled plasma (ICP) spectroscopy. The solubility was evaluated in terms of the stepwise complexation of iron by fluoride ions at different ionic strength and temperature. The solubility of beta-FeF3-3H(2)O increases with decreasing concentration of HF and HNO3 and increasing temperature.

  • 50.
    Österdahl, Kerstin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Tjus, Kåre
    IVL.
    Fortkamp, Uwe
    IVL.
    Schneiker, Torsten
    Åkesson, S.
    Precipitation of Iron Fluoride Trihydrate from Mixed Acid Pickle Liquors2006In: Iron control Technologies, Proc. 3rd Intern. Symp. on Iron Control in Hydrometallurgy / [ed] Dutrizac, J.E. and Riveros, P.A, Can. Inst. Of Mining, Metallurgy and Petroleum , 2006, p. 845-861Conference paper (Refereed)
1 - 50 of 50
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