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Title: Nano-scale synthesis of the complex silicate minerals forsterite and enstatite

Abstract

Olivine is a relatively common family of silicate minerals in many terrestrial and extraterrestrial environments, and is also useful as a refractory ceramic. A capability to synthesize fine particles of olivine will enable additional studies on surface reactivity under geologically relevant conditions. This paper presents a method for the synthesis of nanocrystalline samples of the magnesium end-member, forsterite (Mg 2SiO 4) in relatively large batches (15–20 g) using a sol-gel/surfactant approach. Magnesium methoxide and tetraethylorthosilicate (TEOS) are refluxed in a toluene/methanol mixture using dodecylamine as a surfactant and tert-butyl amine and water as hydrolysis agents. This material is then cleaned and dried, and fired at 800 °C. Post-firing reaction in hydrogen peroxide was used to remove residual organic surfactant. X-ray diffraction showed that a pure material resulted, with a BET surface area of up to 76.6 m 2/g. Finally, the results of a preliminary attempt to use this approach to synthesize nano-scale orthopyroxene (MgSiO 3) are also reported.

Authors:
 [1];  [1];  [1];  [2];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Gothenburg, Gothenburg (Sweden)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1344274
Alternate Identifier(s):
OSTI ID: 1411824
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Colloid and Interface Science
Additional Journal Information:
Journal Volume: 495; Journal Issue: C; Journal ID: ISSN 0021-9797
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; forsterite; enstatite; olivine; pyroxene; orthopyroxene; clinopyroxene; nanosynthesis

Citation Formats

Anovitz, Lawrence M., Rondinone, Adam Justin, Sochalski-Kolbus, Lindsay, Rosenqvist, Jorgen, and Cheshire, Michael C. Nano-scale synthesis of the complex silicate minerals forsterite and enstatite. United States: N. p., 2017. Web. doi:10.1016/j.jcis.2017.01.052.
Anovitz, Lawrence M., Rondinone, Adam Justin, Sochalski-Kolbus, Lindsay, Rosenqvist, Jorgen, & Cheshire, Michael C. Nano-scale synthesis of the complex silicate minerals forsterite and enstatite. United States. doi:10.1016/j.jcis.2017.01.052.
Anovitz, Lawrence M., Rondinone, Adam Justin, Sochalski-Kolbus, Lindsay, Rosenqvist, Jorgen, and Cheshire, Michael C. Wed . "Nano-scale synthesis of the complex silicate minerals forsterite and enstatite". United States. doi:10.1016/j.jcis.2017.01.052. https://www.osti.gov/servlets/purl/1344274.
@article{osti_1344274,
title = {Nano-scale synthesis of the complex silicate minerals forsterite and enstatite},
author = {Anovitz, Lawrence M. and Rondinone, Adam Justin and Sochalski-Kolbus, Lindsay and Rosenqvist, Jorgen and Cheshire, Michael C.},
abstractNote = {Olivine is a relatively common family of silicate minerals in many terrestrial and extraterrestrial environments, and is also useful as a refractory ceramic. A capability to synthesize fine particles of olivine will enable additional studies on surface reactivity under geologically relevant conditions. This paper presents a method for the synthesis of nanocrystalline samples of the magnesium end-member, forsterite (Mg2SiO4) in relatively large batches (15–20 g) using a sol-gel/surfactant approach. Magnesium methoxide and tetraethylorthosilicate (TEOS) are refluxed in a toluene/methanol mixture using dodecylamine as a surfactant and tert-butyl amine and water as hydrolysis agents. This material is then cleaned and dried, and fired at 800 °C. Post-firing reaction in hydrogen peroxide was used to remove residual organic surfactant. X-ray diffraction showed that a pure material resulted, with a BET surface area of up to 76.6 m2/g. Finally, the results of a preliminary attempt to use this approach to synthesize nano-scale orthopyroxene (MgSiO3) are also reported.},
doi = {10.1016/j.jcis.2017.01.052},
journal = {Journal of Colloid and Interface Science},
number = C,
volume = 495,
place = {United States},
year = {Wed Jan 18 00:00:00 EST 2017},
month = {Wed Jan 18 00:00:00 EST 2017}
}

Journal Article:
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  • No abstract prepared.
  • Nano-forsterite powder with natural silica sand and magnesium powder as the raw materials have been succesfully synthesized. The silica sand was purified followed by a coprecipitation process to obtain colloidal silica. The magnesium powder was dissolved in a chloric acid solution to obtain MgCl{sub 2} solution. The nanoforsterite powder was synthesised using a sol-gel method which included the mixing the colloidal silica and the MgCl{sub 2} solution with various aging and filtering processes. The samples were dried at 100 °C using a hot plate and then the dried powders were calcinated at 900 °C for 2 hours. The samples weremore » characetised for their elements and phase compositions using X-ray Flourescence (XRF) and X-ray Diffraction (XRD) methods, respectively. The diffraction data were qualitatively analyzed using Match!2 software and quantitatively using Rietica software. The crystallite size was verified using Transmission Electron Microscopy (TEM). Results of XRD data analysis showed that the forsterite content reached up to 90.5% wt. The TEM average crystallite size was approximately 53(6) nm.« less
  • Among the thermochemical data for rock-forming minerals in the system MgO--SiO/sub 2/--H/sub 2/O, those for orthoenstatite and for talc are highly uncertain. The tightly-bracketed reactions (1) talc = 3 enstatite + quartz + steam, and (2) talc + forsterite = 5 enstatite + steam permit the simultaneous calculation of the standard Gibbs free energies of formation for both orthoenstatite and talc: -1457.27 +- 4 kJ mol/sup -1/ and -5516.37 +- 10 kJ mol/sup -1/, respectively. Using the calculated free energies of talc and enstatite and six reversed brackets for four reactions involving anthophyllite (Greenwood, 1963), the standard Gibbs free energymore » of formation of anthophyllite was recomputed to be -11,331.8 kJ mol/sup -1/ with an estimated uncertainty of +- 17 kJ mol/sup -1/; this value is more positive than previous estimates because of the revised value for enstatite. The reversed brackets of Johannes (1968) for the reaction clinochrysotile + brucite = 2 forsterite + 3 steam were used to calculate the free energy of formation of clinochrysotile. The value obtained (-4,030.84 +- 4.0 kJ mol/sup -1/) agrees well with published values. As an independent check, the free energy of talc was calculated, using the calculated free energy of clinochrysotile and a single reversed bracket for the reaction 5 clinochrysotile = 6 forsterite + talc + steam (Chernosky, 1973). The result, -5,522.91 +- 15.62 kJ mol/sup -1/, is in satisfactory agreement with the above-cited value. The results confirm the geometry of the P--T diagram for anthophyllite, enstatite, talc, forsterite, quartz, and steam suggested by Greenwood, through inconsistencies in the slopes of Chernosky's experimental results and those of Greenwood remain to be resolved. Nevertheless, our results indicate that an internally consistent P--T net, using the experimental data of Chernosky (1976) and Greenwood (1963) for anthophyllite, enstatite, talc, forsterite, and quartz, should be possible.« less
  • No abstract prepared.