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  • 1.
    Beheshti, Reza
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Sustainable Aluminum and Iron Production2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aluminium recycling requires 95% less energy than primary production with no loss of quality. The Black Dross (BD) produced during secondary aluminium production contains high amounts of water-soluble compounds, therefore it is considered as a toxic waste. In the present work, salt removal from BD by thermal treatment has been investigated in laboratory scale. The optimum conditions for treatment were established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature. Even Pretreated Black Dross (PBD) was evaluated as a possible raw material for the production of a calcium aluminate-based ladle-fluxing agent to be used in the steel industry. The effects of different process parameters on the properties of the produced flux were experimentally investigated, i.e. CaO/Al2O3 ratio, temperature, holding time, and cooling media. The utilization of PBD as the alumina source during the production of a calcium aluminate fluxing agent shows promising results. The iron/steel industry is responsible for 9% of anthropogenic energy and process CO2 emissions. It is believed that the only way to a long-term reduction of the CO2 emissions from the iron/steel industry is commercialization of alternative processes such as Direct Reduction (DR) of iron oxide. Detailed knowledge of the kinetics of the reduction reactions is, however, a prerequisite for the design and optimization of the DR process. To obtain a better understanding of the reduction kinetics, a model was developed step-by-step, from a single pellet to a fixed bed with many pellets. The equations were solved using the commercial software COMSOL Multiphysics®. The final model considers the reaction rate and mass transfer inside the pellet, as well as the mass transfers and heat transfer in the fixed bed. All the models were verified against experimental results, and where found to describe the results in a satisfying way.

  • 2.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    Akhtar, Shahid
    Aune, Ragnhild E.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    Heat treatment of black dross for the production of a value added material - a preliminary study2012In: EPD Congress 2012, John Wiley & Sons, 2012, p. 353-360Conference paper (Refereed)
    Abstract [en]

    The potential use of Black Dross (BD) as a raw material for the production of refractories, fluxing agents and glasses is the main motivation of the present study. Heat treatment experiments were carried out in Ar, and under reduced pressure (20 Pa), to evaluate the salt removal efficiency. The chemical composition of the BD after heat treatment was investigated by SEM-EDS and XRD analyses. Based on the present results, it is established that the salt starts to evaporate at ≈1273 K in Ar, and under reduced pressure. The salt removal efficiency in a 20 g sample was found to increase in both cases as a function of time and temperature. Moreover, in Ar the chlorine concentration was lowered to 0.3 wt% after heat treatment at 1523 K for 10 hours. Under reduced pressure, however, 0.2 wt% residual chlorine was obtained after 8 hours at 1473 K.

  • 3.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Aune, R. E.
    Automotive Lithium-ion battery recycling: A theoretical evaluation2016In: TMS Annual Meeting, The Minerals, Metals, and Materials Society, 2016, no CONFCODENUMBER, p. 65-71Conference paper (Refereed)
    Abstract [en]

    Lithium-ion Batteries (LiBs) are today used in significant quantities in the automotive industry. As these batteries are expected to last the lifetime of the vehicle, they will not be ending their useful lives in large numbers for another 10-15 years. An opportunity does therefore exist to prepare for some of the roadblocks that might arise during the development of technologies for environmentally sound recycling of LiBs. In view of this, there is a need for reliable thermodynamic and kinetic data so that a secondary product of high enough metal value, as well as quality, can be produced making it possible to find a market for its purpose. In the present study the equilibrium conditions for obtaining the best conditions possible for recovering the metal content through the aluminum recycling process were studied. All thermodynamic calculations were performed using the FactSage™ software, and the chosen chemical compositions represent the two main families of IiBs, i.e. LiNiCOAlO2 and LiFePO4 The possible production of PH3 and P4 (white phosphor) during the recycling process is also briefly discussed.

  • 4.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Moosberg-Bustnes, J.
    Aune, Ragnhild E.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Modeling and simulation of isothermal reduction of a single hematite pellet in gas mixtures of H2 and CO2014In: TMS 2014 143rd Annual Meeting & Exhibition, Annual Meeting Supplemental Proceedings, The Minerals, Metals, and Materials Society, 2014, p. 495-502Conference paper (Refereed)
    Abstract [en]

    In the present project a time dependent computerized model that fairly accurately simulates the isothermal reduction of a hematite pellet with the use of CO and H2 gas mixtures have been developed. The model, which is based on the Shrinking Core Model (SCM), allows for the description of the chemical reactions taking place and the mass transfer conditions existing for each of the gas species present within the pellet. The equations used to describe the different steps are numerically solved with 1D axial symmetric Finite Element Modeling (FEM) using the commercial COMSOL 4.3b software. Small-scale laboratory experiments were also performed under well-controlled conditions to get an understanding for the weight loss of the pellets as a function of time. The results obtained from these experiments were incorporated into the model. The developed model clearly shows some deviations from the experimental results, but this is believed to be due to the existing variations in the shape and size of the pellets, the porosity distribution and the pelletizing history of the industrial pellets.

  • 5.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Nothern Research Institute Narvik, Norway.
    Moosberg-Bustnes, J.
    Kennedy, M. W.
    Aune, R. E.
    Reduction of commercial hematite pellet in isothermal fixed bed-experiments and numerical modelling2016In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 43, no 1, p. 31-38Article in journal (Refereed)
    Abstract [en]

    In the present work, fixed bed reduction experiments were conducted at 1173 K over a range of H-2/CO ratios from 0.8 to 2.0 and subsequently modelled numerically (R). The model consists of two one-dimensional, isothermal and time dependent models. The gas-solid reactions were kinetically modelled using a modified shrinking core approach, and the equations were solved using the commercial software COMSOL Multiphysics H. The simulation results agree with thermal gravity experimental data with an average difference of 2.5%. A sensitivity analysis was conducted using the numerical model to establish the optimum operational conditions. The effects of the reducing gas ratio and flow rate, pellet radius and porosity, and the total bed height on the overall degree of reduction were also investigated.

  • 6.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Northern Research Institute, Norway.
    Moosberg-Bustnes, John
    Akhtar, Shahid
    Aune, Ragnhild E.
    Black Dross: Processing Salt Removal from Black Dross by Thermal Treatment2014In: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 66, no 11, p. 2243-2252Article in journal (Refereed)
    Abstract [en]

    The salt removal from black dross by thermal treatment has experimentally been studied under different conditions in both a stationary resistance furnace and in a laboratory scale rotary furnace. The experiments were designed based on partial pressure calculations using the Thermo-Calc software (Thermo-Calc Software, Stockholm, Sweden). The salt removal efficiency was evaluated by scanning electron microscope (SEM) energy-dispersive x-ray spectroscopy and x-ray diffraction analyses, and the optimum conditions for treatment established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature, as well as by reduced pressure. Under atmospheric pressure, the highest degree of chloride removal from a 20 g sample was obtained after 10 h at 1523 K resulting in a 98% removal and a final chloride content of 0.3 wt.% in the residue. Under reduced pressure, the chloride concentrate was lowered to 0.2 wt.% after thermal treatment of a 20 g sample at 1473 K for 8 h. In the case of 200 g samples treated in a rotary furnace, the chloride concentrate was 2.5 wt.% after 14 h at 1523 K, representing a removal of 87%. Below 0.3 wt.% chloride content, the material is deemed a nonhazardous waste.

  • 7.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Moosberg-Bustnes, John
    Akhtar, Shahid
    Aune, Ragnhild.E.
    Black Dross Processing: Utilization of Black Dross in the Production of a Ladle Fluxing Agent2017In: Journal of Sustainable Metallurgy, ISSN 2199-3831, Vol. 3, no 2, p. 265-273Article in journal (Refereed)
    Abstract [en]

    In the present study, black dross (BD) residue, a hazardous by-product generated during secondary aluminum production, has been evaluated as a possible raw material for the production of a calcium aluminate-based ladle fluxing agent to be used in the steel industry. The thermally treated BD [pretreated black dross (PBD)] used as a starting material, consisted of approximately 49.5 ± 3.5 wt% alumina and 0.3 wt% chloride. The effects of different process parameters on the properties of the produced flux were experimentally investigated, i.e., the CaO/Al2O3 ratio, the sintering temperature and time, and the cooling medium. The prepared samples were all sintered in a rapid high-temperature inductive furnace, and later characterized by SEM–EDS, XRD, XRF, and DTA/TG analyses. Dissolution tests were also performed using a synthetic slag simulating the carryover. Based on the presently obtained results, it can be concluded that the utilization of PBD as the alumina source during the production of a calcium aluminate fluxing agent shows promising results, and the optimum process conditions were established to be 1523 K for 15 min as the sintering temperature and time, water as the cooling medium, and a CaO/Al2O3 ratio of 0.94. Utilizing PBD as a raw material in the production of a value-added product would significantly reduce the need for the disposal of BD as a waste, and thereby help to decrease the overall environmental impact. It would also provide economic benefit to both the steel and aluminum industry.

  • 8.
    Beheshti, Reza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Northern Research Institute Narvik, Norway.
    Moosberg-Bustnes, John
    Kennedy, Mark W.
    Aune, Ragnhild E.
    Reduction kinetics of commercial haematite pellet in a fixed bed at 1123-1273 K2016In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 43, no 5, p. 394-402Article in journal (Refereed)
    Abstract [en]

    In the present study a model for future use in the modelling of moving bed direct reduction reactors has been developed. The model of a fixed bed reactor for the production of sponge iron from haematite incorporates both heat-and mass-transfer, as well as the chemical reduction rate. The model results were compared to the experimental data obtained from a lab scale reactor in the temperature range 1123-1273 K, as well as to the output from a simple model assuming isothermal conditions. The H-2/CO ratio (beta) of the reducing gas was in all cases varied from 0.8 to 2.0. Overall the non-isothermal model developed permits a more accurate representation of the experimental data than the isothermal estimates, with a typical discrepancy of only 1.3%.

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