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Conversion of chrysotile to a magnesian smectite

Published online by Cambridge University Press:  01 January 2024

Michael Cheshire  and
Necip Gũven
Michael Cheshire*
Affiliation:
Texas Tech University, Department of Geosciences, Lubbock, TX 79419, USA
Necip Gũven
Affiliation:
Texas Tech University, Department of Geosciences, Lubbock, TX 79419, USA
*
*E-mail address of corresponding author: [email protected]
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Abstract

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Chrysotile from Thetford Mines in Quebec, Canada was treated first with mild formic or oxalic acid at concentrations of 0.5 to 2.0 N at 200°C in Teflon-lined 12.0 mL Parr bombs. The reaction products were identified by X-ray diffraction as a poorly crystalline Fe-bearing kerolite-like 2:1 layer silicate (which will be described as a kerolitic precipitate or a kerolitic mesophase in this report). Electron microscopic examination showed a thin foily morphology for this kerolitic mesophase that may have formed by the following reaction:(1)

$\mathop {{\rm{M}}{{\rm{g}}_{\rm{6}}}{\rm{S}}{{\rm{i}}_{\rm{4}}}{{\rm{O}}_{{\rm{10}}}}{{\left( {{\rm{OH}}} \right)}_{{8_{\left( {\rm{s}} \right)}}}}}\limits_{{\rm{chrysotile}}} + 6.02{{\rm{H}}^{\rm{ + }}}_{\left( {{\rm{aq}}} \right)} + 0.54{\rm{F}}{{\rm{e}}^{{\rm{2 + }}}}_{\left( {{\rm{aq}}} \right)} \to \mathop {\left( {{\rm{M}}{{\rm{g}}_{{\rm{2}}{\rm{.46}}}}{\rm{Fe}}_{{\rm{0}}{\rm{.54}}}^{{\rm{2 + }}}} \right){\rm{S}}{{\rm{i}}_{\rm{4}}}{{\rm{O}}_{{\rm{10}}}}{{\left( {{\rm{OH}}} \right)}_{\rm{2}}} \cdot n}\limits_{{\rm{kerolitic}}\;{\rm{mesophase}}} {{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\left( {\rm{s}} \right)}} + {\rm{3}}{\rm{.55M}}{{\rm{g}}^{{\rm{2 + }}}}_{\left( {{\rm{aq}}} \right)}$

The magnetite impurity in the initial chrysotile asbestos served as the source of Fe in the above reactions. Subsequently, this kerolitic precipitate was reacted with 0.2 N NaOH for 48–96 h at 200°C and a highly crystalline smectite was formed with the same foily morphology as the kerolitic precipitate. X-ray spectral analyses of the kerolitic mesophase and smectite suggest the following reaction to have taken place:(2)

$\eqalign{ & \mathop {\left( {{\rm{M}}{{\rm{g}}_{{\rm{2}}{\rm{.46}}}}{\rm{Fe}}_{{\rm{0}}{\rm{.54}}}^{{\rm{2 + }}}} \right){\rm{S}}{{\rm{i}}_{\rm{4}}}{{\rm{O}}_{{\rm{10}}}}{{\left( {{\rm{OH}}} \right)}_{\rm{2}}}}\limits_{{\rm{kerolitic}}\;{\rm{mesophase}}} \cdot n{{\rm{H}}_{\rm{2}}}{{\rm{O}}_{\left( {\rm{s}} \right)}} + {\rm{0}}{\rm{.53M}}{{\rm{g}}^{{\rm{2 + }}}}_{\left( {{\rm{aq}}} \right)} + 0.54{\rm{NaO}}{{\rm{H}}_{\left( {{\rm{aq}}} \right)}} + 0.01{\rm{F}}{{\rm{e}}^{{\rm{3 + }}}}_{\left( {{\rm{aq}}} \right)} \to \cr & \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\mathop {\;\;{\rm{N}}{{\rm{a}}_{0.54}}\left( {{\rm{M}}{{\rm{g}}_{{\rm{2}}{\rm{.99}}}}{\rm{Fe}}_{{\rm{0}}{\rm{.01}}}^{{\rm{2 + }}}} \right)\left( {{\rm{S}}{{\rm{i}}_{{\rm{3}}{\rm{.46}}}}{\rm{Fe}}_{{\rm{0}}{\rm{.54}}}^{{\rm{3 + }}}} \right){{\rm{O}}_{10}}{{\left( {{\rm{OH}}} \right)}_{{\rm{2}}\;\left( {\rm{s}} \right)}}}\limits_{{\rm{saponite}}} + 0.54{\rm{S}}{{\rm{i}}^{{\rm{4 + }}}}_{\left( {{\rm{aq}}} \right)} \cr} $

The reaction products, a kerolitic mesophase and smectite, possess a non-fibrous habit in contrast to the fibrous (asbestiform) morphology of chrysotile.

Keywords

AsbestosChrysotileHydrothermal ConversionKeroliteSmectite
Type
Research Article
Information
Clays and Clay Minerals , Volume 53 , Issue 2 , April 2005 , pp. 155 - 161
Copyright
Copyright © Clay Minerals Society 2005

References

Barbeau, C. and Ledoux, R.L., (1979) Evaluation of chrysotile by chemical methods Mineralogical Techniques of Asbestos Determination Toronto, Canada Mineralogical Association of Canada 197–212.Google Scholar
Bell, J.L. Wesolowski, D.J. and Palmer, D.A., (1993) The dissociation quotients of formic acid in sodium chloride solutions to 200°C Journal of Solution Chemistry 22 125–136 10.1007/BF00650679.Google Scholar
Choi, I. and Smith, R.W., (1972) Kinetic study of dissolution of asbestos fibers in water Journal of Colloid and Interface Science 40 253–262 10.1016/0021-9797(72)90014-8.Google Scholar
Chowdhury, S., (1975) Kinetics of leaching of asbestos minerals at body temperature Journal of Applied Chemical and Biotechnology 25 347–353 10.1002/jctb.5020250505.Google Scholar
Elton, N.J. Hooper, J.J. and Holyer, V.A.D., (1997) An occurrence of stevensite and kerolite in the Devonian Crousa gabbro at Dean Quarry, The Lizard, Cornwall, England Clay Minerals 32 241–252 10.1180/claymin.1997.032.2.06.Google Scholar
Goldstein, J.I., Hren, J.T. Goldstein, J.I. and Joy, D.C., (1979) Principles of thin film X-ray micro-analysis Introduction to Analytical Electron Microscopy New York and London Plenum Press 83–120 10.1007/978-1-4757-5581-7_3.Google Scholar
Güven, N. and Subedi, R. (2002) Using a PC-based Lab VIEW Program for Acquiring and Processing X-Ray Diffraction Data. .Google Scholar
Harris, D.C., (1991) Quantitative Chemical Analysis 3rd New York W.H. Freeman and Company 782 pp.Google Scholar
Kettler, R.M. Palmer, D.A. and Wesolowski, D.J., (1991) Dissociation quotients of oxalic acid in aqueous sodium chloride media to 175°C Journal of Solution Chemistry 20 905–926 10.1007/BF01074952.Google Scholar
Kloprogge, J.T. Komarneni, S. and Amonette, J., (1999) Synthesis of smectite clay minerals: a critical review Clay and Clay Minerals 47 529–554 10.1346/CCMN.1999.0470501.Google Scholar
Pozo, M. and Casas, J., (1999) Origin of kerolite and associated Mg clays in palustrine-lacustrine environments. The Esquivias deposit (Neogene Madrid Basin, Spain) Clay Minerals 34 395–418 10.1180/000985599546316.Google Scholar
Seida, Y. Nakano, Y. and Nakamura, Y., (2002) Crystallization of layered double hydroxides by ultrasound and the effects of crystal quality on their surface properties Clays and Clay Minerals 50 525–532 10.1346/000986002320514244.Google Scholar
Vaillancourt, A. Denes, G. and Le Van Mao, R., (1997) Reactivity of chrysotile asbestos in acids: mechanisms of transformation to silicon dioxide hemihydrate upon leaching of magnesium Materials Research Society Symposium Proceedings 453 71–76 10.1557/PROC-453-71.Google Scholar
Veblen, D.R. Wylie, A.G., Guthrie, G.D. and Mossman, B.T., (1993) Mineralogy of amphiboles and 1:1 layer silicates Health Effects of Mineral Dusts Washington, D.C Mineralogical Society of America 61–137 10.1515/9781501509711-006.Google Scholar
Wicks, F.J. O’Hanley, D.S. and Bailey, S.W., (1988) Serpentine minerals: structure and petrology Hydrous Phyllosilicates Washington, D.C Mineralogical Society of America 91–159 10.1515/9781501508998-010.Google Scholar