H.c. Starck Gmbh

H. C. Starck, Gmbh & Co Kg

H.c. Starck Tungsten Gmbh

Wolfgang Mathy

Juliane Meese-Marktscheffel

Viktor Stoller

Wilfried Gutknecht

Armin Olbrich

Michael Erb

Gerhard Gille

Michael Lohse

The invention is directed to a method for the production of ammonium paratungstate tetrahydrate by thermal treatment of ammonium paratungstate decahydrate in an aqueous suspension. The ammonium paratungstate tetrahydrate can be produced with high purity and high yield. The production method may furthermore be carried out in a simple and energy-efficient manner.

Method for production of ammonium paratungstate tetrahydrate and highly pure ammonium paratungstate tetrahydrate

Process for the electrochemical decomposition of precursors in powder form by introducing a powder batch between two electrodes of an electrolysis cell, electrodes being designed to be liquid-permeable, and the electrolyte flowing through the powder batch perpendicularly to the electrode surfaces, and electrolysis cell suitable therefor, which is essentially characterized in that at least one electrode has a structure which consists of a supporting pierced plate (), an electrode plate () provided with perforations, and a filter cloth () arranged between the supporting pierced plate () and the electrode plate (), and in that the cathode () is shielded from the cell by means of a liquid-permeable separator ().

Process for the electrochemical decomposition of powders and electrolysis cells suitable therefor

A process for elution of rhenium adsorbed on strongly basic ion-exchange resins by means of highly concentrated aqueous hydrochloric acid solution is described, in which the ion-exchange resin is treated with aqueous solution containing an oxidizing agent.

Process for isolating rhenium

Method for extracting anions

Process for treating tungstate solutions to reduce molybdenum impurity

Process for producing pure ammonium metallates

Process for the production of pure tungsten and/or molybdenum solutions from sources, such as alkaline decomposition solutions, which are contaminated with tantalum, niobium, titanium, aluminium, tin, arsenic, phosphorus and/or silicon, by application of a three stage purification process of pH reduction, anion exchange and membrane electrolysis.

Process for the production of pure solutions of tungsten and molybdenum

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Langelsheim, Germany

Wolfgang Mathy