H.c. Starck Gmbh

H. C. Starck, Gmbh & Co Kg

H. C. Starck Gmbh & Co

H.c. Starck Tungsten Gmbh

Viktor Stoller

Juliane Meese-Marktscheffel

Armin Olbrich

Michael Erb

Gerhard Gille

Frank Schrumpf

Wolfgang Mathy

Josef Schmoll

Michael Lohse

Wolfgang Kummer

Ulrich Krynitz

Klaus-Jürgen Marschall

Mathias Benz

Evelyn Pross

Dirk Naumann

Ricarda Leiberich

Sven Albrecht

Peter Axmann

Christoph Schild

Daniel Gordon Duff

Margret Wohlfahrt-Mehrens

Matthias Jahn

Astrid Gorge

Michael Kruft

Rüdiger Zertani

Gerd Maikowske

Wolfgang Schweda

Sandra Ströbele

Herbert Dittrich

Astrid Görge

Benno Decker

Daniel Duff

Karl-Heinz Heine

The invention is directed to ammonium paratungstate decahydrate containing at least 75% of crystals having a length of at least 200 &#x3bc;m and having a ratio of length to width of less than 4.5:1.

Ammonium paratungstate hydrates and ammonium paratungstate decahydrate

A method for preparing ammonium heptamolybdate with the steps of:

Method for producing ammonium heptamolybdate

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

The invention is directed to a process for the continuous preparation of ammonium paratungstate hydrate by back reextraction of a tungsten-laden organic phase with an ammonia-containing aqueous solution in a mixer-settler apparatus. The reextraction is carried out at an NH:W molar ratio of from 0.83 to 1.30, and a volume feed ratio of the tungsten-laden organic phase to the ammonia-containing aqueous solution of from 5 to 25. The above crystalline is in high purity and in high yield. The production method can be carried out in a simple and energy-efficient manner.

Method for producing ammonium paratungstate hydrates and ammonium paratungstate decahydrate

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 preparing nickel hydroxide by alkaline precipitation from nickel salt solutions in the presence of complexing agents, in which the precipitation is carried out at at least two different locations in the same mother liquor with different precipitation kinetics at the different locations and the mother liquor is mixed prior to agglomeration of the precipitated primary crystals, is described.

Nickel hydroxide and method for producing same

A process for reducing the content of alkali metal impurities (e.g., potassium) in ammonium metallate solutions is described. The process involves subjecting a feed solution containing ammonium metallate and alkali metal impurities to membrane filtration. The membrane filtration results in the formation of a retentate having a reduced level alkali metal relative to the feed solution, and a permeate containing substantially the balance of alkali metal. The permeate may also be further treated, to remove alkali metal there from, by passage through a cation exchange column, thereby forming a cation exchange treated permeate that may be combined with the retentate of the membrane filtration step.

Purification of ammonium metallate solutions

The invention relates to a method for producing metal hydroxides or alkaline metal carbonates by anode dissolution of the corresponding metals and precipitation of the hydroxides or alkaline carbonates in an aqueous medium. The anode dissolution of the metal components is carried out in the anode compartment of a three-compartment electrolytic cell. An aqueous auxiliary salt solution is fed to an intermediate compartment that is disposed between the anode compartment and the cathode compartment and that is separated therefrom by a porous membrane. An at least not alkaline metal salt solution is continuously taken from the anode compartment while an alkaline auxiliary salt solution is continuously taken from the cathode compartment. The at least not alkaline metal salt solution and the alkaline auxiliary salt solution are combined outside the electrolytic cell for the purpose of precipitating metal hydroxides or alkaline metal carbonates.

Method for producing metal hydroxides or alkaline metal carbonates

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

The invention relates to a method for producing lithium-transition metal mixtures of general formula Li(MM)O, wherein Mrepresents nickel, cobalt or manganese, Mrepresents chromium, cobalt, iron, manganese, molybdenum or aluminium, and is different from M, n is 2 if Mrepresents manganese and is 1 otherwise, x is comprised between 0.9 and 1.2, y is comprised between 0.5 and 1.0 and z is comprised between 1.9 and 2.1. According to the inventive method, an intimate mixture composed of transition metal compounds containing oxygen and of a lithium compound containing oxygen is calcinated, said mixture being obtained by processing a solid powder transition metal compound with a solution of said lithium compound, and then drying. At least the Mcompound is used in powder form having a specific surface of at least 20 m/g (BET) and calcination is carried out in a fluidised bed.

Method for producing lithium-transition metal mixtures

The invention relates to a nickel mixed hydroxide with Ni as the main element and with a layer structure, comprising at least one element Mfrom the group comprising Fe, Cr, Co, Ti, Zr and Cu which is present in two different oxidation states which differ by one electron in terms of the number of outer electrons; at least one element Mfrom the group comprising B, Al, Ga, In and RE (rare earth metals) present in the trivalent oxidation state; optionally at least one element Mfrom the group comprising Mg, Ca, Sr, Ba and Zn present in the divalent oxidation state; apart from the hydroxide, at least one additional anion from the group comprising halides, carbonate, sulfate, oxalate, acetate, borate and phosphate in a quantity sufficient to preserve the electroneutrality of the mixed hydroxide; and water of hydration in a quantity which stabilizes the relevant structure of the mixed hydroxide.

Nickel mixed hydroxide, method for the producing the same, and the use thereof as a cathode material in alkaline batteries

A nickel hydroxide for rechargeable batteries which is provided with a cobalt hydroxide coating which is stable to oxidation is described. The stability to oxidation is achieved by covering the surface of the cobalt hydroxide layer with anions of weak inorganic oxygen acids.

Nickel hydroxide coated with cobaltous hydroxide

A process is described for the production of spherical nickel hydroxide by anodic dissolution of a nickel electrode and precipitation of nickel hydroxide in a completely intermixed electrolysis cell, wherein an electrolysis brine is used which has a content of 20 to 50 g/l of chloride ions and 1 to 7 g/l of ammonia with a pH value of 9.5 to 11.5 and a temperature of 45 to 60&deg; C.

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Bad Harzburg, Germany

Viktor Stoller