Description of an aerodynamic levitation apparatus with applications in Earth sciences

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.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.The term aerodynamic levitation is used for a technique, in which solids or liquids are freely floated on top of a vertical gas stream. With this technique, samples are not in contact with any container material. Therefore, aerodynamic levitation allows the conduction of high-temperature experiments while avoiding problems related to the chemical interaction between sample and container walls (e.g., corrosion of oxide crucibles by silicate melts [1,2], gain or loss of siderophile elements and Fe in Pt crucibles, [3,4]).Oxides and silicates can be heated and melted with a CO2 gas laser [5], a mirror furnace [6], or a solar furnace [7], while they are floating on top of the gas stream. Depending on the supplied energy, temperatures >3000°C