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Silicon nanopowders were prepared by hot-wire chemical vapour deposition (CVD) from monosilane. Wire materials including Hf, Nb, Ta, Mo, W, Rh, Re, Ir, Pd, and Pt were tested. The filament temperature was varied in the range of 400 -2000°C and pressures between 1.0 -1.5 bar.Products were characterised by bulk elemental analysis and a laser granulometer. The powders were investigated by TG-DSC-MS under inert, O 2 , and H 2 O containing atmosphere, respectively, in a temperature range of 20 -700°C. Hydrogen evolution occurred in three separate steps, depending on the applied gas atmosphere. The oxidation mechanism was explored by the characteristic O x Si-H bands (x = 0 -3) observed in ex situ DRIFT experiments. The oxidation of hydrogen terminated silicon surfaces was investigated employing oxygen (O 2 ), hydrogen peroxide (H 2 O 2 ), permanganate (MnO − 4 ), or peroxodisulfate S 2 O 2− 8 in a temperature range of 0 -120°C. The oxidation was stepwise and strongly enhanced after pretreatment by alkyl lithium salts or Grignard reagents.

Ehemalige Bergbau‐ und Hüttenhalden sind aufgrund ihres Rohstoffpotenzials ins Blickfeld des Interesses gerückt. Mit modernen, angepassten Verfahren der Pyro‐ und Hydrometallurgie sind heute verbesserte Möglichkeiten der Aufbereitung gegeben, ausgewählte Elemente anzureichern und einer Weiterverarbeitung zuzuführen. Eine hohe Wertschöpfung bietet die Rückgewinnung von Zinn aus Tailingmaterial der früheren Kassiteritaufbereitung. Durch Reduktion des Metalloxids und nachfolgender Abtrennung ist ein vielversprechender Weg gegeben, Zinn aus Rückständen zu gewinnen und dem Rohstoffkreislauf zuzuführen.

Gas phase ammonolysis of volatile metal chlorides at elevated temperatures is a favorable way to produce nitride or oxynitride nanopowders. Their composition as well as the physico-chemical properties is determined by reaction temperature, molar ratio of the reactants and the residence time of the gases in the reaction zone. Both single and multi component powders can be obtained. Typical particle sizes are in the range of 50 to 350 nm. The specific surface can reach values up to 300 m2/g. Microporous analysis revealed the presence of pores with a diameter between 0.6 and 0.7 nm in amorphous silicon nitride. The powders can be used, depending on the characteristics, as catalyst or basic catalyst support. The paper gives an overview about vapor phase synthesis of single and multi component nitrides as well as the use of amorphous silicon nitride as a basic catalyst support for dehydrogenation of propane.