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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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Photography of the reduced lherzolite-metal oxide mixture. Metal exsolved from the silicate. The diameter of the sphere was ~2 mm. The material was levitated with a mixture of 98 vol.% Ar and 2 vol.% H2.
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Figure 14: Photography of the reduced lherzolite-metal oxide mixture. Metal exsolved from the silicate. The diameter of the sphere was ~2 mm. The material was levitated with a mixture of 98 vol.% Ar and 2 vol.% H2.

Mentions: The starting material was fused in a graphite crucible to a small sphere. The sphere was placed in the nozzle in the closed sample chamber in order to maintain a reducing atmosphere. The levitation gas was a commercially available mixture of 98 vol.% Ar and 2 vol.% H2 for ~10 min. The oxide-lherzolite mixture was levitated and melted for about 5 min in the reducing gas atmosphere. The experimental run product consisted of a silicate fraction and metal (Fig. 14). The metal sphere pointed towards the bottom of the levitation nozzle during melting. Both phases were liquid during the course of the experiment. The surface of the silicate sphere shows marks of skeletal olivine crystals that formed during quenching.


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

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

Photography of the reduced lherzolite-metal oxide mixture. Metal exsolved from the silicate. The diameter of the sphere was ~2 mm. The material was levitated with a mixture of 98 vol.% Ar and 2 vol.% H2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 14: Photography of the reduced lherzolite-metal oxide mixture. Metal exsolved from the silicate. The diameter of the sphere was ~2 mm. The material was levitated with a mixture of 98 vol.% Ar and 2 vol.% H2.
Mentions: The starting material was fused in a graphite crucible to a small sphere. The sphere was placed in the nozzle in the closed sample chamber in order to maintain a reducing atmosphere. The levitation gas was a commercially available mixture of 98 vol.% Ar and 2 vol.% H2 for ~10 min. The oxide-lherzolite mixture was levitated and melted for about 5 min in the reducing gas atmosphere. The experimental run product consisted of a silicate fraction and metal (Fig. 14). The metal sphere pointed towards the bottom of the levitation nozzle during melting. Both phases were liquid during the course of the experiment. The surface of the silicate sphere shows marks of skeletal olivine crystals that formed during quenching.

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