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G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar

G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar. San Antonio, TX. CaCO 3 & magnetic field. C alcium carbonate nucleation and crystallization in high magnetic fields G. Drazic, S. Kobe, P. McGuiness, S. Knez *, J. Strazisar* Jozef Stefan Institute, Jamova 39, Ljubljana,

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G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar

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  1. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar San Antonio, TX CaCO3 & magnetic field • Calcium carbonate nucleation and crystallization in high magnetic fields • G. Drazic, S. Kobe, P. McGuiness, • S. Knez*, J. Strazisar* • Jozef Stefan Institute, Jamova 39, Ljubljana, • *Faculty of Natural Sciences, • University of Ljubljana • Slovenia ACA 2002

  2. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio • Scale formation (tap water pipes) heating of tap water calcium carbonate scale prevention: chemicals chemical pollution of the environment Introduction 4 cm thick scale in the tap water tube http://www.dhvi.com/applications_fluidentry.htm nucleation and crystallization of calcium carbonate could be influenced by a magnetic field.

  3. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio 1945: First patent (Belgium) commercial devices are used for decades 2002: How it works? (Does it work at all?) • Reported effects: • decrease of scale formation • decrease of the nucleation rate of CaCO3 • formation of soft scale with different structure • increase ratio of aragonite / calcite • memory effect • different particle size • no effects at all Yesterday & today

  4. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio • Hypothesis: • changes in structure of (liquid) water • changes in electro-kinetic zeta potential • direct effect of the magnetic field on precipitation • heterogeneous nucleation of CaCO3 on FeOOH (goethite) • the influence of Zn2+ and Cu2+ (and Si4+) ions • Lorentz-force induced deformation of diffuse layer Explanations Scope of the present work: preliminary study of nucleation & crystallization using analytical electron microscopy

  5. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio • Model solution • dissolving fine CaCO3 powder by bubbling CO2 gas • membrane filtering • equilibrium system of CaCO3 - Ca(HCO3)2 - H2O Experimental TEM sample C/Cu grid t1 t2 t3 • Precipitation: • heating (CO2 is removed) • blowing air through the solution (0.05 - 0.5 l/min)

  6. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio treatment time: 8h XRD analysis XRD spectra of treated samples: MWT - in magnetic field (1.4T) and NT - without the magnetic field

  7. samples Calcite Aragonite Vaterite untreated 34% 14% 52% mag. treated 14% 44% 42% G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Mass percentages of crystal forms (calculated from XRD): XRD analysis J. Strazisar, S. Knez, S. Kobe, The influence of the magnetic field on the zeta potential of precipitated calcium carbonate, International Congress for Particle Technology, Partec 2001, Nuerenberg, Germany

  8. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Nucleation Early stages of crystallization Phase identification Chemical composition (elemental) Estimating the fraction of various phases Transmission EM TEM Jeol 2000 FX,Jeol 2010 F (FEG) EDXS Link Isis

  9. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Phase identification Particles of Calcite, Aragonite and Vaterite found in samples

  10. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Beam damage • Decomposition of Vaterite phase under electron beam (formation of CaO)

  11. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio t1 Morphology magnetic field without the field

  12. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio t2 Particle size magnetic field without the field

  13. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio t1 magnetic field Amorphous phase contain high amount of Si EDXS analysis

  14. G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio t1 magnetic field EDXS analysis without the field t1 vaterite Si is present in many particles treated in magnetic field

  15. samples Calcite Aragonite Vaterite mag. field 10% 30% 60% no field 20% 20% 60% samples Calcite Aragonite Vaterite mag. field 50% 10% 40% no field 55% 5% 40% G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Ratio of crystal forms (area) (estimated from TEM): t1 Ratio of phases t2

  16. Conclusions: effectmagnetic field without the field morphology (t1) poor well defined morphology (t2,3) well well defined particle size (t1) much smaller much larger particle size (t2) smaller larger particle size (t3) similar similar Si presence yes no calcite/aragonite higher(?) lower (?) G. Drazic, S. Knez, S. Kobe, P. McGuiness, J. Strazisar CaCO3 & magnetic field ACA 2002 San Antonio Conclusions . . . courtesy by Mr. Zoran Samardzija

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