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Centre National De La Recherche Scientifique

Université De Bourgogne

Centre National De La Recherche Scientifique-cnrs

Frédéric Bernard

Zuhair A Munir

Hervé Muhr

Daniel Aymes

Moustapha Ariane

Frédéric Demoisson

Eric Gaffet

Frederic Charlot

The present invention relates to a method for continuously preparing mineral particles by means of the thermolysis of mineral precursors in an aqueous medium, comprising contacting: a reactive flow, including mineral precursors at a temperature lower than the conversion temperature thereof; and a heat transfer flow that is countercurrent to said reactive flow and contains water at a temperature that is sufficient to bring the precursors to a temperature higher than the conversion temperature thereof, the mixture flow that results from said reactive flow and said heat transfer flow then being conveyed into a tubular reactor, inside of which particles are formed by gradually converting the precursors, and where the reactive flow and the heat transfer flow are placed in contact with each other inside a mixing chamber, inside of which the reactive flow and the heat transfer flow are fed by supply pipes having outlet cross-sections that are smaller than the maximum cross-section of said mixing chamber. The invention also relates to a device for implementing said method.

Particle synthesis by means of the thermohydrolysis of mineral precursors

Solid reaction products with a dense nanocrystalline structure are formed from reactant particles with diameters in the nano-scale range by compacting the particles into a green body, then passing an electric current through the body causing Joule heating sufficient to initiate the reaction to form the reaction product while simultaneously applying pressure to the reacting body to density it to a density approaching the theoretical density of the pure product. Surprisingly, this process results in a reaction product that retains the nanocrystalline structure of the starting materials, despite the fact that a reaction has occurred and the materials have been subjected to highly stringent conditions of electric current, heat and pressure.

One-step synthesis and consolidation of nanophase materials

Growing community of inventors

Neuilly-les-Dijon, France

Frédéric Bernard