H.c. Starck Gmbh

Leah F. Simkins

Leonid Natan Shekhter

Hugh P. Greville

Leonid Lanin

Leonid L Lanin

Terrance B Tripp

Anastasia M Conlon

Howard V Goldberg

Karlheinz Reichert

Oliver Thomas

Leah F Simkins

Michael J Albarelli

Anastasis M Conlon

Hugh P Greville

Joachim Vieregge

Leonid Natan Shekter

The invention relates to a process that involves (1) feeding (a) a first valve metal powder component containing valve metal particles and (b) reducing component into a reactor having a hot zone; and (2) subjecting the first valve metal powder component and the reducing component to non-static conditions sufficient to simultaneously (i) agglomerate the first valve metal powder component particles, and (ii) reduce oxygen content in the valve metal powder component particles, and thereby form a second valve metal powder component containing oxygen-reduced valve metal particles, in which the reducing component is selected from the group consisting of magnesium reducing components, calcium reducing components, aluminum reducing components, lithium reducing components, barium reducing components, strontium, reducing components, and combinations thereof.

Production of valve metal powders with improved physical and electrical properties

High purity refractory metals, valve metals, refractory metal oxides, valve metal oxides, or alloys thereof suitable for a variety of electrical, optical and mill product/fabricated parts usages are produced from their respective oxides by metalothermic reduction of a solid or liquid form of such oxide using a reducing agent that establishes (after ignition) a highly exothermic reaction, the reaction preferably taking place in a continuously or step-wise moving oxide such as gravity fall with metal retrievable at the bottom and an oxide of the reducing agent being removable as a gas or in other convenient form and unreacted reducing agent derivatives being removable by leaching or like process.

Metalothermic reduction of refractory metal oxides

A method of producing a refractory metal powder that includes providing a metal powder containing magnesium tantalate or magnesium niobate; and heating the powder in an inert atmosphere in the presence of magnesium, calcium and/or aluminum to a temperature sufficient to remove magnesium tantalate or magnesium niobate from the powder and/or heating the powder under vacuum to a temperature sufficient to remove magnesium tantalate or magnesium niobate from the powder, the heating steps being performed in any order. The metal powder can be formed into pellets at an appropriate sintering temperature, which can be formed into electrolytic capacitors.

Magnesium removal from magnesium reduced metal powders

A method of preparing primary refractory metals (e.g., primary tantalum metal) by contacting a particulate refractory metal oxide (e.g., tantalum pentoxide) with a heated gas (e.g., a plasma), is described. The heated gas comprises hydrogen gas. The temperature range of the heated gas and the mass ratio of hydrogen gas to refractory metal oxide are each selected such that: (i) the heated gas comprises atomic hydrogen; (ii) the refractory metal oxide feed material is substantially thermodynamically stabilized (i.e., the concurrent formation of suboxides that are not reduced by atomic hydrogen is minimized); and (iii) the refractory metal oxide is reduced by contact with the heated gas, thereby forming primary refractory metal (e.g., primary tantalum metal and/or primary niobium metal).

Method of preparing primary refractory metal

Metal powder Ta and/or Nb, with or without one or metals from the group Ta, Nb, Ti, Mo, W, V, Zr and Hf, is made in a fine powder form by reduction of metal oxide by contact with a gaseous reducing agent, preferably an alkaline earth metal, to near complete reduction, leaching, further deoxidation and agglomeration, the powder so produced being sinterable to capacitor anode form and processable to other usages.

Metal powders produced by the reduction of the oxides with gaseous magnesium

Metal powder from the group Ta, Nb, Ti, Mo, W, V, Zr, Hf preferrably Ta or Nb, is made in a fine powder form by reduction of metal oxide by contact with a gaseous reducing agent, preferrably an alkaline earth metal, to near complete reduction, leaching, further deoxidation and agglomeration, the powder so produced being sinterable to capacitor anode form and processable to other usages.

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Belmont, MA, United States of America

Leonid L Lanin