Abstract: 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.

Abstract: 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 NH3: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.

Abstract: 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.

Abstract: Process for the production of a powdered spherical tungstic acid by acidification of an aqueous alkaline tungstate solution with mineral acid at elevated temperature, preferably in a continuous stirred tank or a cascade of at least 2 continuous stirred tanks, and tungstic acid obtainable in this way, which is characterised by a high bulk density and spherical morphology.

Abstract: The invention relates to a device and a method for the production of compounds by precipitation of solids from solutions, the physical and chemical properties of the solid particles formed on precipitation being flexible and can be independently fixable. Custom products can thus be produced with very high space-time yields and a particulate nickel/cobalt mixed hydroxide of formula NixCo1-x(OH)2, with a BET surface area of 20 m2/g and a tap density of greater than 2.4 g/cm3.

Abstract: Process for the production of a powdered spherical tungstic acid by acidification of an aqueous alkaline tungstate solution with mineral acid at elevated temperature, preferably in a continuous stirred tank or a cascade of at least 2 continuous stirred tanks, and tungstic acid obtainable in this way, which is characterized by a high bulk density and spherical morphology.

Abstract: The invention is directed to a pulverulent compound of the formula NiaM1bM2bOx(OH)y where M1 is at least one element selected from the group consisting of Fe, Co, Zn, Cu and mixtures thereof, M2 is at least one element selected from the group consisting of Mn, Al, Cr, B, Mg, Ca, Sr, Ba, Si and mixtures thereof, 0.3?a?0.83, 0.1?b?0.5, 0.01?c?0.5, 0.01?x?0.99 and 1.01?y?1.99, wherein the ratio of tapped density measured in accordance with ASTM B 527 to the D50 of the particle size distribution measured in accordance with ASTM B 822 is at least 0.2 g/cm3·?m. The invention is also directed to a method for the production of the pulverulent compound and the use as a precursor material for producing lithium compounds for use in lithium secondary batteries.

Abstract: A process for preparing a pure ammonium perrhenate includes producing a first aqueous suspension containing an ammonium perrhenate. A stoichiometric amount of a nitric acid is added to the first aqueous suspension so as to produce a second suspension. The second suspension is introduced into a cathode space of an electrolysis cell. The electrolysis cell is divided by a cation-exchange membrane into the cathode space and an anode space. The nitric acid is cathodically reduced to a nitrous acid in the cathode space by applying an electric potential. The nitrous acid is reacted with ammonium ions of the ammonium perrhenate so as to form an aqueous perrhenic acid. Potassium ions are removed from the aqueous perrhenic acid. At least a stoichiometric amount of ammonia is added to the aqueous perrhenic acid so as to produce the pure ammonium perrhenate.

Abstract: 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.

Abstract: Powdery compounds of the formulation NiaMbOx(OH)y, a procedure to produce the same, and the use of the same as active material for nickel metal hydride batteries and/or as precursor for the production of lithium compounds for use in secondary lithium batteries.

Abstract: 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 (5), an electrode plate (3) provided with perforations, and a filter cloth (4) arranged between the supporting pierced plate (5) and the electrode plate (3), and in that the cathode (6) is shielded from the cell by means of a liquid-permeable separator (7).

Abstract: 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 NH3: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.

Abstract: 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.

Abstract: A method for preparing ammonium heptamolybdate with the steps of: i) adding a molybdenum-containing organic phase to a liquid-liquid reextraction apparatus or to a desorption apparatus and adding an ammonia-containing aqueous solution to this reextraction or desorption apparatus, and ii) directly cold-crystallizing ammonium heptamolybdate by cooling the resulting reextraction or desorption solution.

Abstract: The invention relates to a process for recovering valuable metals from a superalloy which has the steps of digesting the superalloy in a salt melt. The salt melt contains 60-95% by weight of NaOH and 5-40% by weight of Na2SO4.

Abstract: 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.

Abstract: A process for recovery of valuable metals from superalloys by electrochemical decomposition is described, both electrodes being formed by the superalloy and the polarity of the electrolysis current being reversed with a frequency of from 0.005 to 5 Hz.

Abstract: 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 (5), an electrode plate (3) provided with perforations, and a filter cloth (4) arranged between the supporting pierced plate (5) and the electrode plate (3), and in that the cathode (6) is shielded from the cell by means of a liquid-permeable separator (7).

Abstract: Process for the production of a powdered spherical tungstic acid by acidification of an aqueous alkaline tungstate solution with mineral acid at elevated temperature, preferably in a continuous stirred tank or a cascade of at least 2 continuous stirred tanks, and tungstic acid obtainable in this way, which is characterised by a high bulk density and spherical morphology.

Abstract: 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.