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Description of an aerodynamic levitation apparatus with applications in Earth sciences.

Pack A, Kremer K, Albrecht N, Simon K, Kronz A - Geochem. Trans. (2010)

Bottom Line: We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal.Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.

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Affiliation: Georg-August-Universität, Geowissenschaftliches Zentrum, Goldschmidtstraße 1, D-37077 Göttingen, Germany. apack@uni-goettingen.de.

ABSTRACT

Background: In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO2-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.

Results: Liquid silicate droplets (~2 mm) were maintained stable in levitation using a nozzle with a 0.8 mm bore and an opening angle of 60°. The gas flow was ~250 ml min-1. Rock powders were melted and homogenized for microchemcial analyses. Laser melting produced chemically homogeneous glass spheres. Only highly (e.g. H2O) and moderately volatile components (Na, K) were partially lost. The composition of evaporated materials was determined by directly combining levitation and inductively coupled plasma mass spectrometry. It is shown that the evaporated material is composed of Na > K > Si. Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal.

Conclusions: Levitation melting is a rapid technique or for the preparation of bulk rock powders for major, minor and trace element analysis. With exception of moderately volatile elements Na and K, bulk rock analyses can be performed with an uncertainty of ± 5% relative. The technique has great potential for the quantitative determination of evaporated materials from silicate melts. Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.

No MeSH data available.


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Plots showing the major and minor element composition of quenched spheres (1 - 4 times fused) of rhyolite standard RGM-1. The element concentrations were normalized to the reference concentrations [38] and to Al (see text for details). The 1σ error bars are outlined.
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Figure 8: Plots showing the major and minor element composition of quenched spheres (1 - 4 times fused) of rhyolite standard RGM-1. The element concentrations were normalized to the reference concentrations [38] and to Al (see text for details). The 1σ error bars are outlined.

Mentions: We have displayed all data with normalization on the concentration of the respective reference value of the element and on Al (Figs. 5, 6, 7 and 8). The measured to reference ratios were normalized to Al because this was the most refractory [i.e. has the highes evaporation temperature; [31,39]] major element in the samples and was not expected to be lost by evaporation. This is common practice when displaying chemical data with respect to volatility. A ratio of one indicates that the respective element was not lost during melting. A ratio <1 indicates evaporation. In such a case, the respective value gives the fraction of the element that remained in the sample. A ratio exceeding unity can only be due to sample heterogeneity.


Description of an aerodynamic levitation apparatus with applications in Earth sciences.

Pack A, Kremer K, Albrecht N, Simon K, Kronz A - Geochem. Trans. (2010)

Plots showing the major and minor element composition of quenched spheres (1 - 4 times fused) of rhyolite standard RGM-1. The element concentrations were normalized to the reference concentrations [38] and to Al (see text for details). The 1σ error bars are outlined.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2958152&req=5

Figure 8: Plots showing the major and minor element composition of quenched spheres (1 - 4 times fused) of rhyolite standard RGM-1. The element concentrations were normalized to the reference concentrations [38] and to Al (see text for details). The 1σ error bars are outlined.
Mentions: We have displayed all data with normalization on the concentration of the respective reference value of the element and on Al (Figs. 5, 6, 7 and 8). The measured to reference ratios were normalized to Al because this was the most refractory [i.e. has the highes evaporation temperature; [31,39]] major element in the samples and was not expected to be lost by evaporation. This is common practice when displaying chemical data with respect to volatility. A ratio of one indicates that the respective element was not lost during melting. A ratio <1 indicates evaporation. In such a case, the respective value gives the fraction of the element that remained in the sample. A ratio exceeding unity can only be due to sample heterogeneity.

Bottom Line: We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal.Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.

View Article: PubMed Central - HTML - PubMed

Affiliation: Georg-August-Universität, Geowissenschaftliches Zentrum, Goldschmidtstraße 1, D-37077 Göttingen, Germany. apack@uni-goettingen.de.

ABSTRACT

Background: In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO2-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments.

Results: Liquid silicate droplets (~2 mm) were maintained stable in levitation using a nozzle with a 0.8 mm bore and an opening angle of 60°. The gas flow was ~250 ml min-1. Rock powders were melted and homogenized for microchemcial analyses. Laser melting produced chemically homogeneous glass spheres. Only highly (e.g. H2O) and moderately volatile components (Na, K) were partially lost. The composition of evaporated materials was determined by directly combining levitation and inductively coupled plasma mass spectrometry. It is shown that the evaporated material is composed of Na > K > Si. Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal.

Conclusions: Levitation melting is a rapid technique or for the preparation of bulk rock powders for major, minor and trace element analysis. With exception of moderately volatile elements Na and K, bulk rock analyses can be performed with an uncertainty of ± 5% relative. The technique has great potential for the quantitative determination of evaporated materials from silicate melts. Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.

No MeSH data available.


Related in: MedlinePlus