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Kundu, Tarun
Publications (10 of 10) Show all publications
Rao, K. H., Kundu, T. & Forssberg, E. (2006). Atomistic simulation on the adsorption of water, methanoic acid and methylamine on pure and hydroxylated quartz (ed.). In: (Ed.), Güven Önal (Ed.), Proceedings of the XXIII International Mineral Processing Congress: Istanbul, Turkey 3 - 8 September 2006. Paper presented at International Mineral Processing Congress : 03/09/2006 - 08/09/2006 (pp. 1729-1735). Istanbul: IMPC
Open this publication in new window or tab >>Atomistic simulation on the adsorption of water, methanoic acid and methylamine on pure and hydroxylated quartz
2006 (English)In: Proceedings of the XXIII International Mineral Processing Congress: Istanbul, Turkey 3 - 8 September 2006 / [ed] Güven Önal, Istanbul: IMPC , 2006, p. 1729-1735Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Istanbul: IMPC, 2006
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-28668 (URN)28d41700-d61f-11db-8550-000ea68e967b (Local ID)28d41700-d61f-11db-8550-000ea68e967b (Archive number)28d41700-d61f-11db-8550-000ea68e967b (OAI)
Conference
International Mineral Processing Congress : 03/09/2006 - 08/09/2006
Note
Godkänd; 2006; Bibliografisk uppgift: CD-ROM; 20070319 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Kundu, T., Rao, K. H. & Parker, S. (2006). Atomistic simulation studies of magnetite surface structures and adsorption behavior in the presence of molecular and dissociated water and formic acid (ed.). Paper presented at . Journal of Colloid and Interface Science, 295(2), 364-373
Open this publication in new window or tab >>Atomistic simulation studies of magnetite surface structures and adsorption behavior in the presence of molecular and dissociated water and formic acid
2006 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 295, no 2, p. 364-373Article in journal (Refereed) Published
Abstract [en]

Static energy minimization techniques have been used to elucidate the surface structures of magnetite crystals in pure and hydroxylated forms. Adsorption energy values in the presence of molecular water, dissociate water and simple carboxylic group molecule (formic acid) are calculated and we found that the carboxylic group do not adsorb strongly in most of the pure and hydroxylated surfaces in comparison to water. Since the associated calcium minerals are floated from magnetite using fatty acid collector, our calculations corroborate the flotation practice of removing these impurity minerals from magnetite.

National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-3808 (URN)10.1016/j.jcis.2005.09.022 (DOI)000235744600007 ()2-s2.0-32544459753 (Scopus ID)1a5799a0-b120-11db-bf9d-000ea68e967b (Local ID)1a5799a0-b120-11db-bf9d-000ea68e967b (Archive number)1a5799a0-b120-11db-bf9d-000ea68e967b (OAI)
Note
Validerad; 2006; 20070131 (pafi)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Kundu, T., Rao, H. & Parker, S. (2005). Competitive adsorption on wollastonite: an atomistic simulation approach (ed.). Paper presented at . Journal of Physical Chemistry B, 109(22), 11286-11295
Open this publication in new window or tab >>Competitive adsorption on wollastonite: an atomistic simulation approach
2005 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 22, p. 11286-11295Article in journal (Refereed) Published
Abstract [en]

Atomistic simulation techniques are used to simulate surface structure and adsorption behavior of scarcely floatable wollastonite mineral in the presence of molecular and dissociated water, methanoic acid, and methylamine. The latter two additives represent the two widely used collector head-group molecules. The static energy minimization code METADISE was used to perform the simulation to obtain pure surface energy and adsorption energy in the presence of added molecule. The hydroxylation was performed on those surfaces where low-coordinated silicon was made to saturate by bonding with hydroxyl group, and the subsequent charge neutralization was maintained by adding proton on single-coordinated surface oxygen. A comparison of surface energies revealed that all the surfaces become stabilized in the presence of added molecules; however, the presence of methylamine decreased the surface energy to lower values. Adsorption of dissociated water is preferred by the {100} and {102} surfaces, whereas the {001} surface preferred methylamine adsorption, because these show highly negative adsorption energies. In terms of molecular adsorption, the preferred adsorption sequence for all the surfaces is methylamine > methanoic acid > water without considering coadsorption. For the {100} and {102} surfaces, the adsorption energy values of carboxylic acid and amine are more negative than that of water and therefore we conclude that both carboxyl and amine head-group molecules adsorb preferably on wollastonite. Our simulation verify usability of carboxylic acid head group as widely used collectors for wollastonite flotation and, at the same time, it predicts the use of amine head-group collectors as possible modifiers, which corresponds well with our experimental findings.

National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-12294 (URN)10.1021/jp0580367 (DOI)000229589700029 ()2-s2.0-20744436512 (Scopus ID)b67ea5d0-6913-11db-8cbe-000ea68e967b (Local ID)b67ea5d0-6913-11db-8cbe-000ea68e967b (Archive number)b67ea5d0-6913-11db-8cbe-000ea68e967b (OAI)
Note
Validerad; 2005; 20061031 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Rao, K. H., Kundu, T., Parker, S. & Forssberg, E. (2005). Molecular modelling of mineral surface structures and adsorption phenomena in flotation (ed.). In: (Ed.), (Ed.), Centenary of Flotation Symposium Proceedings: . Paper presented at Centenary of Flotation Symposium : 06/06/2005 - 09/06/2005 (pp. 557-572). : The Australian Institute of Mining and Metallurgy, Paper ID: 505086
Open this publication in new window or tab >>Molecular modelling of mineral surface structures and adsorption phenomena in flotation
2005 (English)In: Centenary of Flotation Symposium Proceedings, The Australian Institute of Mining and Metallurgy , 2005, Vol. Paper ID: 505086, p. 557-572Conference paper, Published paper (Refereed)
Abstract [en]

Understanding the fundamental principles governing the reactions at surfaces has always been the goal of theoretical surface science. The atomistic simulation techniques have been used to calculate the surface structures and the stability of quartz and wollastonite, and their adsorption behaviour in the presence of molecular and dissociative water, and the two widely used collector head group molecules of methanoic acid and methylamine. The dissolution behaviour of wollastonite has also been modelled. The calculated surface energy, hydration energy and reaction energy values have been examined and discussed in the light of flotation literature. These studies have given an insight into the interactions at atomic level, which indicate that modelling techniques should be capable of predicting the adsorption behaviour and to design the selective collector molecules, which is of central importance to the mineral processing technique of flotation.

Place, publisher, year, edition, pages
The Australian Institute of Mining and Metallurgy, 2005
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-38273 (URN)c9e2f280-fa21-11db-b2dd-000ea68e967b (Local ID)c9e2f280-fa21-11db-b2dd-000ea68e967b (Archive number)c9e2f280-fa21-11db-b2dd-000ea68e967b (OAI)
Conference
Centenary of Flotation Symposium : 06/06/2005 - 09/06/2005
Note
Godkänd; 2005; 20070504 (ysko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Kundu, T. (2004). Atomistic simulation techniques for modelling inorganic/organic interface and flotation collector design (ed.). (Doctoral dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Atomistic simulation techniques for modelling inorganic/organic interface and flotation collector design
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The choice of collector molecules in flotation process of mineral separation is invariably determined by tedious trial and error experimentation with inherent mounting expenditure. Here, we seek the help of atomistic simulation techniques, to help and judge the suitable collector molecule for selective mineral separation in flotation process, before actually conducting the experiment. This was the domain where we can attempt theoretically to determine the selective collector while considering different molecular structures of collectors having various head groups that attribute specific interactions with different exposed mineral surfaces in their pure or hydroxylated or activated form. By this we can have insight of the structure of heteropolar collector molecule in flotation separation through electrostatic, stereochemical and geometrical matching with active adsorption sites underlying the molecular recognition mechanisms. The quantitative aspect of adsorption is also obtained while comparing the adsorption energy values. Static energy minimisation code METADISE has been used to construct and describe predominant surfaces of quartz and wollastonite crystals structure in atomic scale. The potential parameters used in simulation predict the crystal cell parameters satisfactorily. The stability of surfaces is compared by surface energy calculations. Seven predominant surfaces of scarcely floatable wollastonite have been modelled and their calculated surface energy corresponds well with their preferred morphological domination. Surfaces are identified having four-fold and three-fold coordination of surface silicon. Three fold surface silicons are stabilized by addition of hydroxyl ion on it and proton on surface oxygen. Stable surfaces thus obtained are subjected to surface Ca2+ replacement by 2H+ by transforming 2O2- to 2OH-. Surface energy and reaction energy values indicate wollastonite surface stabilized to a great extent by adsorbing water in dissociated form and Ca2+ replacement is energetically favourable in acidic condition up to few layers from the surface. Atomistic simulation techniques are used to simulate surface structure and adsorption behavior of wollastonite mineral in the presence of molecular and dissociated water, formic acid and methylamine. A comparison of surface energies revealed that all the surfaces become stabilized in the presence of added molecules but the presence of methylamine decreased the surface energy to lower values. Adsorption of dissociated water is preferred by {100} and {102} surfaces, while {001} surface preferred methylamine adsorption as these show highly negative adsorption energies. In terms of molecular adsorption, the preferred adsorption sequence for all the surfaces is methylamine > formic acid > water without considering co-adsorption. For {100} and {102} surfaces, the adsorption energy values of carboxylic acid and amine are more negative than that of water and therefore we conclude that both carboxyl and amine head group molecules adsorb preferably on wollastonite. Our simulation verify usability of carboxylic acid head group as widely used collectors for wollastonite flotation and at the same time it predict use of amine head group collectors as possible modifier which correspond well with our experimental findings. Surface energies of quartz are calculated and unsaturated surface sites are identified by using the same code. Hydroxylation is carried out in order to satisfy full coordination of surface sites. It revealed that quartz surfaces are most stabilised when they adsorb water in dissociated form justifying hydroxylated quartz surface prevalence in nature. Water, formic acid, and methylamine adsorption calculations are carried out on both pure and hydroxylated quartz surfaces. Relative adsorption energies suggest that both formic acid and methylamine adsorb preferably than water on pure quartz surface. In case of adsorption on hydroxylated quartz methylamine shows great deal of adsorption preference than water and formic acid, which match with flotation practice of quartz by cationic amine collectors. Relaxed atomic positions of surface atoms have been studied for ¦Á-Fe2O3 (0001), (10¨©2), (10¨©0), (10¨©1), (01¨©2), (11 0) and the inverse spinel Fe3O4 (001), (011), (101), (110) and (111) surfaces. Water is added on these surfaces both as molecular and dissociated forms and corresponding surface configuration and relative adsorption energies and calculated. Water adsorption is also carried out on hydroxylated surfaces. Formic acid adsorption is studied both on pure and hydroxylated surfaces. The aim of the present work is to determine the most important faces of each iron oxide by calculating their surface energies, to discuss their surface structure and the effects of relaxation under vacuum conditions. The results are discussed and where possible, compared with experimental data.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2004. p. 56
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544 ; 2004:37
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-17019 (URN)12b0ada0-6f7f-11db-962b-000ea68e967b (Local ID)12b0ada0-6f7f-11db-962b-000ea68e967b (Archive number)12b0ada0-6f7f-11db-962b-000ea68e967b (OAI)
Note

Godkänd; 2004; 20061025 (haneit)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Kundu, T., Rao, K. H. & S.C., P. (2003). Atomistic simulation of the surface structure of wollastonite (ed.). Paper presented at . Chemical Physics Letters, 377(1-2), 81-92
Open this publication in new window or tab >>Atomistic simulation of the surface structure of wollastonite
2003 (English)In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 377, no 1-2, p. 81-92Article in journal (Refereed) Published
Abstract [en]

Atomistic simulation techniques have been used to calculate the surface structure and stability of wollastonite crystal. Seven predominant surfaces have been modelled and their calculated surface energy corresponds well with their morphological domination. The surface energy, hydration energy and reaction energy values indicate wollastonite surfaces stabilized to great extent by adsorbing water in dissociated form. The Ca2+ replacement from the first few layers of the surface is found to be energetically more favourable, elucidating high dissolution phenomena of wollastonite mineral.

National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-2726 (URN)10.1016/S0009-2614(03)01097-2 (DOI)000184680000015 ()2-s2.0-0141562155 (Scopus ID)069739e0-b18e-11de-8293-000ea68e967b (Local ID)069739e0-b18e-11de-8293-000ea68e967b (Archive number)069739e0-b18e-11de-8293-000ea68e967b (OAI)
Note
Validerad; 2003; 20091005 (hrao)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Kundu, T., Rao, K. H. & S.C., P. (2003). Atomistic simulation studies of surface structure of hematite and magnetite crystals and adsorption behaviour of water (ed.). In: (Ed.), K.S. Raju; S.K. Ghosh; A. Majumdar; A.K. Nandi; A.T. Sutone; A.S. Bhoge (Ed.), International Seminar on Mineral Processing Technology: MPT-2003. Paper presented at International Seminar on Mineral Processing Technology : 06/02/2003 - 08/02/2003 (pp. 190-197). New Dehli: Allied Publishers Ltd
Open this publication in new window or tab >>Atomistic simulation studies of surface structure of hematite and magnetite crystals and adsorption behaviour of water
2003 (English)In: International Seminar on Mineral Processing Technology: MPT-2003 / [ed] K.S. Raju; S.K. Ghosh; A. Majumdar; A.K. Nandi; A.T. Sutone; A.S. Bhoge, New Dehli: Allied Publishers Ltd , 2003, p. 190-197Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New Dehli: Allied Publishers Ltd, 2003
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-37633 (URN)bb4a9010-b18b-11de-8293-000ea68e967b (Local ID)81-7764-405-X (ISBN)bb4a9010-b18b-11de-8293-000ea68e967b (Archive number)bb4a9010-b18b-11de-8293-000ea68e967b (OAI)
Conference
International Seminar on Mineral Processing Technology : 06/02/2003 - 08/02/2003
Note
Godkänd; 2003; 20091005 (hrao)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Kundu, T., Rao, K. H., S.C., P. & Forssberg, E. (2002). Atomistic simulation techniques for designing mineral specific collector molecules in froth flotation (ed.). In: (Ed.), S. Subramanian; K.A. Natarajan; B.S. Rao; T.R.R. Rao (Ed.), International Seminar on Mineral Processing Technology (MPT-2002): . Paper presented at International Seminar on Mineral Processing Technology : 03/01/2002 - 05/01/2002 (pp. 272-287). Bangalore: Indian Institute of Science, Department of Mechanical Engineering, 1
Open this publication in new window or tab >>Atomistic simulation techniques for designing mineral specific collector molecules in froth flotation
2002 (English)In: International Seminar on Mineral Processing Technology (MPT-2002) / [ed] S. Subramanian; K.A. Natarajan; B.S. Rao; T.R.R. Rao, Bangalore: Indian Institute of Science, Department of Mechanical Engineering , 2002, Vol. 1, p. 272-287Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Bangalore: Indian Institute of Science, Department of Mechanical Engineering, 2002
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-38975 (URN)d8b71f20-b185-11de-8293-000ea68e967b (Local ID)81-901714-0-2 (ISBN)d8b71f20-b185-11de-8293-000ea68e967b (Archive number)d8b71f20-b185-11de-8293-000ea68e967b (OAI)
Conference
International Seminar on Mineral Processing Technology : 03/01/2002 - 05/01/2002
Note
Godkänd; 2002; 20091005 (hrao)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Kundu, T. (2002). Atomistic simulation techniques for modelling inorganic/organic interface and flotation collector design (ed.). (Licentiate dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Atomistic simulation techniques for modelling inorganic/organic interface and flotation collector design
2002 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The choice of collector molecules in flotation process of mineral separation is invariably determined by tedious trial and error experimentation with inherent mounting expenditure. Here, we seek the help of computational solid chemistry techniques, namely the atomistic simulation techniques, to help and judge the suitable collector molecule for selective mineral separation in flotation process, before actually conducting the experiment. This was the domain where we can attempt theoretically to determine the selective collector while considering different molecular structures of collectors having various head groups that attribute specific interactions with different exposed mineral surfaces in their pure or hydroxylated or activated form. By this we can have insight of the structure of heteropolar collector molecule in flotation separation through electrostatic, stereochemical and geometrical matching with active adsorption sites underlying the molecular recognition mechanisms. The quantitative aspect of adsorption is also obtained while comparing the adsorption energy values. Static energy minimisation code METADISE has been used to construct and describe predominant surfaces of quartz and wollastonite crystals structure in atomic scale. The potential parameters used in simulation predict the crystal cell parameters satisfactorily. The stability of surfaces is compared by surface energy calculations. Seven predominant surfaces of scarcely floatable wollastonite have been modelled and their calculated surface energy corresponds well with their preferred morphological domination. Surfaces are identified having four-fold and three-fold coordination of surface silicon. Three fold surface silicons are stabilized by addition of hydroxyl ion on it and proton on surface oxygen. Stable surfaces thus obtained are subjected to surface Ca2+ replacement by 2H+ by transforming 2O2- to 2OH-. Surface energy and reaction energy values indicate wollastonite surface stabilized to a great extent by adsorbing water in dissociated form and Ca2+ replacement is energetically favourable in acidic condition up to few layers from the surface. Simulations were performed to study the adsorption behaviour of wollastonite in the presence of molecular and dissociated water, and two widely used collector head groups, i.e., carboxylic and amine groups, on three morphologically predominant Miller indexed surfaces. Surface reconstruction were carried out to make the surface free of lone oxygen and surface cuts terminating with fully coordinated silicon were chosen and used for most of the simulation work for adsorption of molecules. The hydroxylation was carried out on those surfaces where low coordinated silicon was made to saturate by bonding with hydroxyl group and the subsequent charge neutralization was maintained by adding proton on single coordinated surface oxygen. A comparison of surface energies revealed that all the surfaces become stabilized in the presence of added molecules but methylamine decreased surface energy to lowest values. Adsorption of dissociated water is preferred by {100} and {102} surfaces, while {001} preferred to adsorb methylamine as these show highly negative adsorption energies. In terms of pure molecules adsorption, the preferred adsorption sequence for all the surfaces is methylamine > methanoic acid > water. Since the {100} and {102} surfaces are the two most predominant and the difference in adsorption energy values are not significant, we conclude a consideration of collector molecules possessing long alkyl chain with head groups considered here cannot adsorb and render hydrophobicity to wollastonite in pure form if no surface activation is carried out, which correspond well with the reported experimental findings. Surface energies of quartz are calculated and unsaturated surface sites are identified by using the same code. Hydroxylation is carried out in order to satisfy full coordination of surface sites. It revealed that quartz surfaces are most stabilised when they adsorb water in dissociated form justifying hydroxylated quartz surface prevalence in nature. Water, methanoic acid, and methylamine adsorption calculations are carried out on both pure and hydroxylated quartz surfaces. Relative adsorption energies suggest that both methanoic acid and methylamine adsorb preferably than water on pure quartz surface. In case of adsorption on hydroxylated quartz methylamine shows great deal of adsorption preference than water and methanoic acid, which match with flotation practice of quartz by cationic amine collectors.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2002. p. 47
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757 ; 2002:16
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-16825 (URN)031d7ba0-c43b-11db-9ea3-000ea68e967b (Local ID)031d7ba0-c43b-11db-9ea3-000ea68e967b (Archive number)031d7ba0-c43b-11db-9ea3-000ea68e967b (OAI)
Note

Godkänd; 2002; 20070224 (ysko)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Kundu, T., Rao, K. H. & Parker, S. (2001). Atomistic simulation techniques for modelling mineral surface reactions (ed.). In: (Ed.), J.M. Cases (Ed.), Advances in the understanding of adsorption phenomena at solid/aqueous solution interfaces: . Paper presented at Advances in the understanding of adsorption phenomena at solid/aqueous solution interfaces : 12/02/2001 - 15/02/2001 (pp. 67-72). : Tata Research Development & Design Centre (TRDDC)
Open this publication in new window or tab >>Atomistic simulation techniques for modelling mineral surface reactions
2001 (English)In: Advances in the understanding of adsorption phenomena at solid/aqueous solution interfaces / [ed] J.M. Cases, Tata Research Development & Design Centre (TRDDC) , 2001, p. 67-72Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Tata Research Development & Design Centre (TRDDC), 2001
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-32102 (URN)67aa3f60-b0ea-11de-8293-000ea68e967b (Local ID)67aa3f60-b0ea-11de-8293-000ea68e967b (Archive number)67aa3f60-b0ea-11de-8293-000ea68e967b (OAI)
Conference
Advances in the understanding of adsorption phenomena at solid/aqueous solution interfaces : 12/02/2001 - 15/02/2001
Note
Godkänd; 2001; 20091004 (hrao)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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