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Seetharaman, Seshadri
Publications (10 of 12) Show all publications
Abbasalizadeh, A., Seetharaman, S., Venkatesan, P., Sietsma, J. & Yang, Y. (2019). Use of iron reactive anode in electrowinning of neodymium from neodymium oxide. Electrochimica Acta, 310, 146-152
Open this publication in new window or tab >>Use of iron reactive anode in electrowinning of neodymium from neodymium oxide
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2019 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 310, p. 146-152Article in journal (Refereed) Published
Abstract [en]

Electrolytic production of metallic neodymium is carried out in fused neodymium fluoride salts containing neodymium oxide. Two major challenges pertaining to neodymium production in fluoride salts are a) low solubility of neodymium oxide in fluoride melt, b) possibility of anodic gas evolution (CO, CO2, CF4, C2F6). In this study, iron is used as a reactive anode in the electrolysis process, promoting electrochemical dissolution of iron into the melt, preventing PFC (perfluorocarbon) gas evolution at the anode. Further, the rare earth oxide is converted to rare earth fluoride by the use of iron fluoride formed as the result of iron dissolution. Thus, the fluoridizing agent is constantly regenerated in-situ which enables the continuous conversion of neodymium oxide feed. The cathodic product is Nd-Fe alloy which can be used as a master alloy for the production of NdFeB magnets. 

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Rare earths, Electrochemical extraction, Reactive anode, PFC gas, Molten salts
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-252586 (URN)10.1016/j.electacta.2019.03.161 (DOI)000467691200016 ()2-s2.0-85065475105 (Scopus ID)
Note

QC 20190611

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2019-06-11Bibliographically approved
Korobeinikov, I. I., Chebykin, D., Yu, X., Seetharaman, S. & Volkova, O. (2018). Density of tin, silver and copper. Archives of Materials Science and Engineering, 92(1), 28-32
Open this publication in new window or tab >>Density of tin, silver and copper
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2018 (English)In: Archives of Materials Science and Engineering, ISSN 1897-2764, Vol. 92, no 1, p. 28-32Article in journal (Refereed) Published
Abstract [en]

Purpose: Purpose of this paper is to report on the development of a new density measure­ment cell. Design/methodology/approach: Measurement cell based on Archimedean principle and consisting of induction furnace and a high/precision balance was applied for measurement of tin, silver and copper density. Findings: It was found that new cell is suitable for high temperature measurement of liquid metals density at temperatures from 700 to 1520°C. Measurement results are in a good agreement with the literature values. Density deviates by 0.5-1% depending on the metal. Research limitations/implications: Accuracy of the density measurement decreases at temperatures below 700°C due to oxidation of the melt surface. More accurate data on thermal expansion coefficient for sinker material is required. Practical implications: Experiments showed applicability of the new measurement cell. Archimedean principle is among the most sensitive density measurement techniques. New cell will be further used for measurement of iron-based alloys. Problems of measurements are discussed. Originality/value: Paper describes application of the known density measurement technique. The paper is of interest for the material scientists working with high-temperature thermophysical properties measurements and users of thermophysical properties data. 

Place, publisher, year, edition, pages
International OCSCO World Press, 2018
Keywords
Archimedes, Copper, Density, Silver, Tin
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-252266 (URN)10.5604/01.3001.0012.5509 (DOI)2-s2.0-85065134609 (Scopus ID)
Note

QC20190607

Available from: 2019-06-07 Created: 2019-06-07 Last updated: 2019-06-07Bibliographically approved
Abbasalizadeh, A., Sridar, S., Chen, Z., Sluiter, M., Yang, Y., Sietsma, J., . . . Hari Kumar, K. C. (2018). Experimental investigation and thermodynamic modelling of LiF-NdF3-DyF3 system. Journal of Alloys and Compounds, 753, 388-394
Open this publication in new window or tab >>Experimental investigation and thermodynamic modelling of LiF-NdF3-DyF3 system
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2018 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 753, p. 388-394Article in journal (Refereed) Published
Abstract [en]

Electrolysis of molten fluorides is one of the promising methods for the recovery and recycling of rare earth metals from used magnets. Due to the dearth of phase equilibria data for molten fluoride systems, thermodynamic modelling of LiF-DyF3-NdF3 system using the CALPHAD approach was carried out. Gibbs energy modelling for LiF-NdF3 and LiF-DyF3 systems was performed using the constitutional data from literature. Ab initio calculations were used to obtain enthalpy of reaction of LiDyF4, an intermediate phase that is found to exist in the LiF-DyF3 system. Differential thermal analysis was carried out for selected compositions in the NdF3-DyF3 system, in order to determine liquidus and solidus temperatures. The Gibbs energy parameters for the limiting binaries determined in this work is used for modelling the Gibbs energy functions of equilibrium phases in the ternary system. Selected compositions of LiF-NdF3-DyF3 were subjected to DTA in order to validate the calculated phase temperatures involving melt.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Calphad, DTA, DyF3-NdF3, LiF-DyF3, LiF-DyF3-NdF3, LiF-NdF3
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-229241 (URN)10.1016/j.jallcom.2018.04.013 (DOI)000432674100049 ()2-s2.0-85046101829 (Scopus ID)
Note

QC 20180601

Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-06-13Bibliographically approved
Sun, Y., Seetharaman, S. & Zhang, Z. (2018). Integrating biomass pyrolysis with waste heat recovery from hot slags via extending the C-loops: Product yields and roles of slags. Energy, 149, 792-803
Open this publication in new window or tab >>Integrating biomass pyrolysis with waste heat recovery from hot slags via extending the C-loops: Product yields and roles of slags
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 149, p. 792-803Article in journal (Refereed) Published
Abstract [en]

The present study characterized a novel route, biomass pyrolysis using the waste heat in high temperature slags via extending the C-loops in the agricultural sector and metallurgy. The equilibrium yields of valuable syngas and biochar were clarified systemically here, in addition to the polluting gases. The results proved that compared to steel slags (SS), blast furnace slags (BFS) only had a limited influence at low temperatures (<700 °C). With respect to SS, there was a transition temperature range in which their roles varied remarkably, i.e., an increase of iron oxide content in SS continuously enhanced the CO yield over 700 °C, whereas a varying basicity mainly affected the pyrolysis results below 700 °C. Regarding the polluting gases, the overall effect of hot slags was quite limited, indicating that no great environmental impacts would be brought in this combined system.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Biomass pyrolysis, C-loop extending, Integrated method, Slag heat recovery, Thermodynamic yields
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-227613 (URN)10.1016/j.energy.2018.02.119 (DOI)000431162100063 ()2-s2.0-85042492239 (Scopus ID)
Note

QC 20180517

Available from: 2018-05-17 Created: 2018-05-17 Last updated: 2018-05-21Bibliographically approved
Kiamehr, S., Ahmed, H., Viswanathan, N. & Seetharaman, S. (2017). Changes in Effective Thermal Conductivity During the Carbothermic Reduction of Magnetite Using Graphite. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 48(3), 1502-1513
Open this publication in new window or tab >>Changes in Effective Thermal Conductivity During the Carbothermic Reduction of Magnetite Using Graphite
2017 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 48, no 3, p. 1502-1513Article in journal (Refereed) Published
Abstract [en]

Knowledge of the effective thermal diffusivity changes of systems undergoing reactions where heat transfer plays an important role in the reaction kinetics is essential for process understanding and control. Carbothermic reduction process of magnetite containing composites is a typical example of such systems. The reduction process in this case is highly endothermic and hence, the overall rate of the reaction is greatly influenced by the heat transfer through composite compact. Using Laser-Flash method, the change of effective thermal diffusivity of magnetite-graphite composite pellet was monitored in the dynamic mode over a pre-defined thermal cycle (heating at the rate of 7 K/min to 1423 K (1150 A degrees C), holding the sample for 270 minutes at this temperature and then cooling it down to the room temperature at the same rate as heating). These measurements were supplemented by Thermogravimetric Analysis under comparable experimental conditions as well as quenching tests of the samples in order to combine the impact of various factors such as sample dilatations and changes in apparent density on the progress of the reaction. The present results show that monitoring thermal diffusivity changes during the course of reduction would be a very useful tool in a total understanding of the underlying physicochemical phenomena. At the end, effort is made to estimate the apparent thermal conductivity values based on the measured thermal diffusivity and dilatations.

Place, publisher, year, edition, pages
Springer, 2017
National Category
Metallurgy and Metallic Materials Energy Engineering
Identifiers
urn:nbn:se:kth:diva-207873 (URN)10.1007/s11663-017-0944-6 (DOI)000400385900010 ()2-s2.0-85014026536 (Scopus ID)
Note

QC 20170530

Available from: 2017-05-30 Created: 2017-05-30 Last updated: 2017-05-30Bibliographically approved
Abbasalizadeh, A., Malfliet, A., Seetharaman, S., Sietsma, J. & Yang, Y. (2017). Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives. JOURNAL OF SUSTAINABLE METALLURGY, 3(3), 627-637
Open this publication in new window or tab >>Electrochemical Extraction of Rare Earth Metals in Molten Fluorides: Conversion of Rare Earth Oxides into Rare Earth Fluorides Using Fluoride Additives
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2017 (English)In: JOURNAL OF SUSTAINABLE METALLURGY, ISSN 2199-3823, Vol. 3, no 3, p. 627-637Article in journal (Refereed) Published
Abstract [en]

In the present research on rare earth extraction from rare earth oxides (REOs), conversion of rare earth oxides into rare earth fluorides with fluoride fluxes is investigated in order to overcome the problem of low solubility of the rare earth oxides in molten fluoride salts as well as the formation of oxyfluorides in the fluorination process. Based on thermodynamic calculations, a series of experiments were performed for converting the rare earth oxides into rare earth fluorides using AlF3, ZnF2, FeF3, and Na3AlF6 as fluorinating agents in a LiF-Nd2O3 system. The formation of neodymium fluoride as a result of the reactions between these fluxes and neodymium oxide is confirmed. The rare earth fluoride thus formed can subsequently be processed through the electrolysis route in the same reactor, and rare earth metal can be produced as the cathodic deposit. In this concept, the REO dissolution in molten fluorides would become unnecessary due to the complete conversion of the oxide into the fluoride, REF3. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2, and FeF3 can act as strong fluorinating agents for the neodymium oxide giving rise to a complete conversion of neodymium oxide into neodymium fluoride.

Place, publisher, year, edition, pages
SPRINGER, 2017
Keywords
Rare earth oxides, Rare earth fluorides, Recycling, Fluorination
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-212328 (URN)10.1007/s40831-017-0120-x (DOI)000406749800017 ()
Note

QC 20170821

Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2017-08-21Bibliographically approved
Abbasalizadeh, A., Malfliet, A., Seetharaman, S., Sietsma, J. & Yang, Y. (2017). Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts. Materials transactions, 58(3), 400-405
Open this publication in new window or tab >>Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts
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2017 (English)In: Materials transactions, ISSN 1345-9678, E-ISSN 1347-5320, Vol. 58, no 3, p. 400-405Article in journal (Refereed) Published
Abstract [en]

In the present work, selective extraction of rare earth (RE) metals from NdFeB magnets is investigated by studying the effects of various fluxes, viz. AlF3, ZnF2, FeF3 and Na3AlF6 in the LiF-NdFeB system. The aim is to convert RE from RE magnet into the fluoride salt melt. The results show the complete selective separation of neodymium (also dysprosium) from the magnet and formation of rare earth fluoride, leaving iron and boron unreacted. The formed rare earth fluoride can subsequently be processed in the same reactor through an electrolysis route so that RE can be deposited as a cathode product. The results of XRD and EPMA analysis of the reacted samples indicate that AlF3, ZnF2 and FeF3 can act as strong fluorinating agents for extraction of rare earth from NdFeB magnet, converting the RE to REF3. The results confirm the feasibility of the rare earth metals recovery from scrap NdFeB magnet as raw material. The fluoride conversion- electrolysis route suggested in the present work enables the extraction of rare earth metals in a single step using the above-mentioned fluxes.

Place, publisher, year, edition, pages
JAPAN INST METALS, 2017
Keywords
rare earth, recycling, rare earth magnet, fluorination
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-205532 (URN)10.2320/matertrans.MK201617 (DOI)000398132300018 ()2-s2.0-85016004685 (Scopus ID)
Note

QC 20170509

Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2017-05-09Bibliographically approved
Abbasalizadeh, A., Seetharaman, S., Venkatesan, P., Sietsma, J. & Yang, Y. (2017). Novel Reactive Anode for Electrochemical Extraction of Rare Earth Metals from Rare Earth Oxides. In: Kim, H Alam, S Neelameggham, NR Oosterhof, H Ouchi, T Guan, X (Ed.), RARE METAL TECHNOLOGY 2017: (pp. 87-92). SPRINGER INTERNATIONAL PUBLISHING AG
Open this publication in new window or tab >>Novel Reactive Anode for Electrochemical Extraction of Rare Earth Metals from Rare Earth Oxides
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2017 (English)In: RARE METAL TECHNOLOGY 2017 / [ed] Kim, H Alam, S Neelameggham, NR Oosterhof, H Ouchi, T Guan, X, SPRINGER INTERNATIONAL PUBLISHING AG , 2017, p. 87-92Conference paper (Refereed)
Abstract [en]

Electrolytic production of metallic neodymium is carried out in fused fluoride salts containing neodymium oxide. Two major challenges pertaining to neodymium production are (a) low oxide solubility, (b) possibility of anodic fluorine gas evolution if the electrolysis rate exceeds feeding rate of neodymium oxide. In this study, a novel method is proposed in which iron fluoride (FeF3) is used as a fluorinating agent to convert neodymium oxide into neodymium fluoride. Electron Probe Micro Analysis (EPMA) results of as-converted salt show a complete conversion of neodymium oxide into neodymium fluoride. In the electrolysis process, iron is used as a reactive anode with electrochemical dissolution of iron into the melt, thus preventing fluorine gas evolution at the anode. Therefore, the fluorinating agent is constantly regenerated in situ which enables the continuous conversion of neodymium oxide feed. The cathodic product is a Nd-Fe alloy which can be directly used as a master alloy for the production of NdFeB permanent magnets.

Place, publisher, year, edition, pages
SPRINGER INTERNATIONAL PUBLISHING AG, 2017
Keywords
Rare earth, Electrochemical extraction, Reactive anode
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-211426 (URN)10.1007/978-3-319-51085-9_9 (DOI)000405305300009 ()2-s2.0-85042256959 (Scopus ID)
Note

QC 20170801

Available from: 2017-08-01 Created: 2017-08-01 Last updated: 2017-08-01Bibliographically approved
Seetharaman, S. (2017). Sustainability, waste processing and secondary resources. Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, 126(1-2), 1-2
Open this publication in new window or tab >>Sustainability, waste processing and secondary resources
2017 (English)In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 126, no 1-2, p. 1-2Article in journal, Editorial material (Refereed) Published
Place, publisher, year, edition, pages
Taylor & Francis, 2017
National Category
Mineral and Mine Engineering
Identifiers
urn:nbn:se:kth:diva-204737 (URN)10.1080/03719553.2017.1283791 (DOI)000396548700001 ()2-s2.0-85011298929 (Scopus ID)
Note

QC 20170601

Available from: 2017-06-01 Created: 2017-06-01 Last updated: 2017-06-30Bibliographically approved
Ahmed, H. M., Viswanathan, N. N. & Seetharaman, S. (2016). Gas-Condensed Phase Reactions - A Novel Route to Synthesize Alloys and Intermetallics Involving Refractory Metals. In: : . Paper presented at Materials Today: Proceedings (pp. 2951-2961). Elsevier (9)
Open this publication in new window or tab >>Gas-Condensed Phase Reactions - A Novel Route to Synthesize Alloys and Intermetallics Involving Refractory Metals
2016 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Reduction and simultaneous reduction-carburization of oxide mixtures to get intermetallics and composite materials may open up shorter process routes towards the end-user needs. The use of natural gas or hydrogen would be environment-friendly. With these aims, the corresponding kinetics were studied by thermogravimetry, gas chromatography as well as laser-flash method. It was found that, under identical conditions, the Arrhenius activation energy for the reduction is proportional to the thermodynamic stability of the compound reduced. Intermetallics could be synthesized successfully and the product was found to have nanograins. Also, Metallic coating on copper surfaces was successfully developed.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Gas-solid reaction, Hydrogen reduction, Intermetallics, Refractory metals
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-201988 (URN)10.1016/j.matpr.2016.09.008 (DOI)000398489200008 ()2-s2.0-84994187862 (Scopus ID)
Conference
Materials Today: Proceedings
Note

QC 20170303

Available from: 2017-03-03 Created: 2017-03-03 Last updated: 2017-05-02Bibliographically approved
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