Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B13/00—Diaphragms; Spacing elements
  • C25B13/04—Diaphragms; Spacing elements characterised by the material
  • C25B13/08—Diaphragms; Spacing elements characterised by the material based on organic materials
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
  • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms

Definitions

• the present invention relates to a method for producing Metal hydroxides and / or metal oxide hydroxides from corresponding metal ions and hydroxide ions, the metal ions being in a membrane electrochemical Process by anodic dissolution of corresponding metals in the anode compartment and the hydroxide ions by cathodic reduction of water in one Anion exchange membrane and the cathode space are formed Hydroxide ions under the driving force of an electric field through the Anion exchange membrane are transferred to the anode compartment.
• Metal hydroxides and metal oxide hydroxides are valuable intermediates for the Production of inorganic or organic salts of these metals, for which corresponding oxides or the pure metals themselves.
• Cobalt hydroxide by calcining a cobalt oxide defined composition e.g. for use in electronics for the production of varistors or Manufacture in batteries or by reducing a cobalt metal powder defined particle size distribution.
• Nickel hydroxides serve as pigments or are available with different dopings and particle structures for use in Batteries inserted.
• Zinc hydroxides can serve as precursors for pigments and the copper compounds can be converted into catalytically active materials.
• Cobalt metal powder made from cobalt hydroxide or Cobalt oxide hydroxide results from its particle size distribution and Particle structure after sintering together with tungsten carbide e.g. specific Carbide tools.
• Nickel hydroxide particles with a Diameters between 1 and 100 ⁇ m are crystallized by a constant pH value and at constant temperature a nickel salt solution and an alkali hydroxide in solid or liquid form with intensive stirring be passed into a reaction vessel.
• Be considered favorable test conditions a pH of 11 and a temperature of 48 ° C.
• a sufficiently compact nickel hydroxide can be produced by precipitation in the presence of ammonia or an ammonium salt.
• a nickel amine complex solution is prepared from nickel nitrate and aqueous ammonia solution, from which a nickel hydroxide is obtained by boiling at ordinary or reduced pressure or by treatment with steam, and which is significantly less specific than the nickel hydroxides which are precipitated in the absence of ammonia Surface area (13 to 20 m 2 / g).
• the production of compact nickel hydroxides in the presence of ammonia or an ammonium salt is also evident from patent applications JP-A 53-6119 and JP-A 61-18107.
• the first-mentioned patent application describes the precipitation of nickel hydroxide by adding an alkali metal hydroxide solution to a corresponding solution with a pH of at least 3.0. Electrochemical investigations on the material produced in this way revealed particularly high specific charge capacities in comparison to commercially available nickel hydroxides.
• a nickel (II) tetrammine salt solution is prepared by dissolving nickel nitrate or nickel sulfate in dilute ammonia solution and decomposed by the controlled addition of sodium hydroxide solution in accordance with the following reaction: Ni (NH 3 ) 4 SO 4 + 2 NaOH ⁇ Ni (OH) 2 + Na 2 SO 4 + 4 NH 3
• the reaction takes place at temperatures between 40 and 50 ° C and in the pH range between 11 and 13.
• the pore volume decreases with decreasing pH. It is expressly stated that a pore-free product can only be crystallized at sufficiently slow reaction rates.
• the nickel hydroxide produced by this process has a high crystallinity, a low specific surface area, a small pore volume and therefore a high physical density.
• the disadvantages of this product due to the high density are also described.
• the small specific surface area results in a lower proton conductivity and a higher current density, which promotes the formation of the undesired ⁇ -NiOOH, which leads to the swelling of the electrode.
• the nickel hydroxide crystallized at low pH values has a high density, it tends to form ⁇ -NiOOH. By choosing an average pH value, a compromise can be found between the required high density and the porosity required to a certain extent.
• This process produces a nickel hydroxide containing 3 to 10% zinc or 1 to 3% magnesium in solid solution. These doping counteract the formation of ⁇ -NiOOH.
• a continuous process for crystallization is known from the patent JP Hei 4-68249 a nickel hydroxide with a spherical particle shape.
• a nickel salt solution 0.5 to 3.5 mol / l
• dilute alkali solution (1.25 to 10 mol / l)
• an ammonia and / or ammonium salt solution continuously with vigorous stirring in an overflow pipe pumped heated cylindrical container
• the ammonia too can be introduced in gaseous form.
• the ammonia concentration is 10 to 28 wt .-% and the ammonium salt concentration with 3 to 7.5 mol / l.
• To complex the nickel between 0.1 and 1.5 mol of ammonia are used Moles of nickel salt solution.
• the system will reach after about 10 to 30 hours a steady state, after which a product with constant Quality can be carried out.
• the dwell time in the container is between 0.5 and 5 hours.
• An essential feature of this process is that the reaction is carried out at a defined pH, which is kept constant at ⁇ 0.1 pH levels in the range between 9 and 12 by pH-controlled supply of alkali metal hydroxide solution, and at a constant temperature in the range between 20 and 80 ° C, the temperature deviations should not be more than ⁇ 2 K.
• the compact spherical particles with a particle size between 2 and 50 ⁇ m are obtained.
• the particle size can be adjusted in particular by varying the NH 3 inflow, the residence time and the stirring speed. The particle size increases with decreasing backspeed or increasing NH 3 inflow. As the dwell time in the container increases, the product becomes coarser and the particle size distribution narrows. The crystals are then filtered, washed with water and dried.
• the product produced by this process has the properties mentioned at the outset and does not need to be ground.
• EP A 462 889 discloses a process for the production of nickel hydroxide.
• the temperature range of the crystallization is above 80 ° C.
• Nitrate or sulfate solutions doped with cobalt, cadmium and / or zinc are used.
• the cobalt content is between 1 and 8% by weight and the cadmium and / or zinc contents are between 3 and 10% by weight.
• Complexation takes place with the aid of an ammonium salt, the NH 3 / Ni molar ratio being between 0.3 and 0.6. This method maintains a pH of 9.2 ⁇ 0.1.
• a three-bladed stirrer is used, the diameter of which is half the size of the container diameter and the speed of rotation is between 300 and 1000 min -1 .
• the product is filtered, washed and dried.
• nickel is used, for example Electrolysis dissolved anodically in a metal salt solution and by cathodically hydroxide ions formed precipitated as nickel hydroxide. After sedimentation and various subsequent washing stages for cleaning the precipitated product of salts which are still present or are included in the precipitation are obtained the pure product.
• JP-A 63/247 385 describes the electrolytic production of metal hydroxides using a perfluorinated anion exchange membrane the Toyo Soda and the use of inert electrodes.
• Electrolyte is the metal salt of the one to be produced on the anode side Related metal hydroxides. There is an alkaline solution in the cathode circuit used. In EP-A 0 559 590 this is described in a comparable arrangement Metal salt continuously added by anodic dissolution of the electrode. The Requirements for the process, especially the membranes to be used, the Electrolyte solutions and the test conditions are insufficiently specified.
• JP-A-63 206 487 describes a process for the production of high-purity Metal hydroxides, with an anode made of the desired metal, for example Indium, dissolved in an electrolyte containing tetramethylammonium hydroxide becomes.
• the cathode is made of platinum and the cell is through an anion exchange membrane divided. Even after electrolysis has ended, there is still one in the anolyte Metal salt solution before, after separation from the anode chamber by heating hydrated to the metal hydroxide.
• DE-A-3 508 360 describes the anodic dissolution of metal mixtures in an ammonium chloride-containing electrolyte using an anion exchange membrane, wherein the metal ions formed on the anode with the im Electrolytes present halogen ions with the formation of halogen complex ions react.
• a metal salt solution in the anolyte there is a metal salt solution in the anolyte.
• the object of this invention is to provide a method for the production of metal hydroxides and / or metal oxide hydroxides, which has the disadvantages of described prior art does not have.
• This object is achieved by a process for the production of metal hydroxides and / or metal oxide hydroxides from corresponding metal ions and Hydroxide ions, the metal ions in a membrane electrochemical process by anodic dissolution of corresponding metals in the anode compartment and the Hydroxide ions by cathodic reduction of water in an anion exchange membrane limited cathode space are formed and the Hydroxide ions under the driving force of an electric field through the Anion exchange membrane can be transferred to the anode compartment characterized in that the dissolution of the metals in the presence of a complexing agent is carried out at a pH> 7 and the formation and precipitation of Metal hydroxide takes place when the solubility limit in the anolyte is exceeded, and the process is carried out continuously, the metal hydroxide formed from Anolyte is separated and the complexing agent is returned to the anode compartment.
• Ammonia is preferred as complexing agent in the sense of this invention and / or organic mono- and / or diamines with a chain length of 1 to 6 carbon atoms used.
• Metals are in particular one or more of the Group Co, Ni, Cu, Fe In, Mn, Sn, Zn, Zr, Ti, Al, Cd and Ni. Especially Co and / or Ni are preferred. The following is the inventive Process further described for the case of the production of nickel hydroxide without thereby restricting the invention.
• the basic configuration for a membrane electrolysis cell the suitable for carrying out the method according to the invention is described below shown.
• the cathode and anode space of the electrolytic cell separated by an anion exchange membrane so that two separate ones Result in cycles.
• the circuit on the side of the cathode is filled with catholyte labeled with anolyte on the anode side.
• the catholyte can be preferred alkaline solutions such as Sodium hydroxide solution or potassium hydroxide solution can be used.
• the solution itself has a high conductivity and the cation of the alkali used is also used on the anode side.
• the cathode itself can be made tempered steel, platinum-plated titanium, nickel or a nickel alloy.
• the composition of the anolyte results from the starting materials for the production of nickel hydroxide, i.e. Ammonia, sodium chloride and small amounts of Nickel sulfate.
• the sodium chloride primarily serves to increase the conductivity the solution and by the slight addition of sulfate the anodic Resolution of the nickel electrode improved. Particularly good results will be achieved when chloride and / or sulfate ions are present in the anolyte.
• the anode itself consists of pure nickel, preferably an electrochemically produced one Anode.
• Ni (OH) 2 Under active transport conditions due to the applied external potential, nickel as Ni 2+ ion dissolves with the release of electrons. The presence of ammonia prevents spontaneous precipitation of Ni (OH) 2 under alkaline conditions and leads to a divalent nickel-amine complex via various intermediates.
• the reaction at the cathode produces hydrogen, the electron uptake gaseous escapes and hydroxide ions, which according to their charge over the Anion exchange membrane are transported into the anode circuit. in the Anolyte then helps to form and precipitate the nickel hydroxide The solubility limit is exceeded. The precipitation follows one dynamic equilibrium, with a ligand exchange (ammonia for Hydroxide) takes place.
• the formation of the spherical product is essentially determined by the crystallization conditions, i.e. the concentration of the individual components and the temperature control determined in the anode circuit.
• the precipitated product will then continuously separated from the anolyte cycle.
• the separation can be done in one procedurally easy to carry out sedimentation tank due to the large difference in density of the product formed and the solvent be performed.
• For separating a product of uniform grain size separation takes place via a filtration stage (microfiltration).
• microfiltration stage microfiltration
• ion exchange membranes usually have one micro-heterogeneous and / or an interpolymer morphology. This is supposed to be achieved that the mechanical and electrochemical properties are decoupled can be adjusted.
• a membrane is constructed accordingly from a matrix polymer, a fabric or a binder, and from one Polyelectrolytes or an ionomer. According to the degree of Heterogeneity of the ion exchange membrane between homogeneous membranes, Interpolymer membranes, micro-heterogeneous graft or block copolymer membranes and heterogeneous membranes.
• the polymer network can be constructed differently in order for the Sufficiently good electrical and mechanical properties in most applications to show.
• a charge neutral matrix polymer is usually Polyvinyl chloride and polyacrylate are used.
• Can be used as further matrix polymers still polyethylene, polypropylene or polysulfone can be used, whereby only these have long-term chemical stability under alkaline conditions.
• an anion exchange membrane one based on polyethylene, polypropylene, polyether ketone, Polysulfone, polyphenyl oxide and / or sulfide used.
• the ion-conducting polyelectrolytes of an anion exchange membrane consist of a network with a positive excess charge and mobile, negatively charged counterions.
• the anion exchange membrane used in the process according to the invention particularly preferably has exchange groups composed of alkylated polyvinylimidazole, polyvinylpyridine and / or alkylated 1,4-diazabicyclo [2.2.2] octane.
• the type and concentration of partitions mainly determines that Permselectivity and the electrical resistance of the membrane, however, can also on the mechanical properties, especially on the swelling of the Impact membrane due to the concentration of fixations.
• the strongly basic quaternary ammonium group is dissociated at all pH values, while the primary ammonium group is only black dissociated. For this reason mostly quaternary ammonium groups in commercial anion exchange membranes built in, except that a membrane with certain properties to be manufactured.
• the fabric should be made of temperature, alkali and oxidation stable polymers (Polypropylene, polyethylene, polyether ketone) exist and as a fixed charge chemically stable quaternary ammonium salt (Vinylimidazole, 4,4'-diaza-bicyclo [2.2.2] octane).
• Suitable membranes are described in DE-A 44 21 126.
• the electrolytic cell is composed of two nickel cathodes, two spacers made of polyethylene, two membranes and the cobalt sacrificial anode and four frames of different thicknesses.
• the cell is constructed in such a way that the nickel cathodes represent the outer sides of the cell with an area of 120 x 200 mm 2 effective electrode area.
• the electrical contact is made on protruding electrode surfaces.
• the cobalt anode consists of pure cobalt with a thickness of 20 mm.
• the entire structure is pressed together in a liquid-tight manner using a holder.
• a PE grid is inserted between the cathodes and the membrane, which prevents contact between the cathode and the membrane.
• the frames that separate the anode and membrane are provided with holes through which the anolyte is fed in and out.
• the cathodes are also provided with feed lines so that a uniform flow of the catholyte is ensured in the entire cathode space.
• the catholyte and anolyte each contain 100 g / l NaCl, the catholyte also 40 g / l NaOH.
• the catholyte is repumped at a rate of 100 l / h, which is one Residence time of the electrolyte in the cathode compartment corresponds to 9 seconds.
• the anolyte is circulated during electrolysis at a speed of 650 l / h pumped, which corresponds to an average residence time of 2.7 seconds in the anode compartment.
• the temperature of the anolyte is 50 ° C.
• the ammonia concentration in the Anolyte is adjusted to 2 mol / l and losses due to evaporation Addition of ammonia in the anolyte circuit balanced.
• the stationary solid concentration of cobalt hydroxides formed is 80 g / l with an average residence time of 4 h.
• the electrolysis conditions are selected so that a current of 12 A corresponding to 500 A / m 2 flows, 21 g of cobalt hydroxide of the form Co (OH) 2 being formed every hour, which are discharged from the circuit in 0.26 l suspension and through Filtration can be separated. After washing with water, a clean cobalt hydroxide is obtained.
• Cobalt hydroxide mixture of Co (OH) 2 with CoOOH in the ratio 80/20 after analysis
• Bulk density 1.6 g / cm 3
• Cobalt content 63.5% colour Dark brown
• an electrolytic cell which is comparable to a stack of electrodes and membranes with the electrode spaces in between is nickel dissolved electrochemically in the presence of ammonia and the formed Ammine complex decomposed to nickel hydroxide.
• Electrolyte composition Anolyte 16.5 mmol / l NiSO 4 220 ml NH 3 (25%) / l 2 mol / l NaCl Catholyte 1 mol / l NaOH anode Pure nickel cathode platinum-plated titanium temperature Electrolysis 40 ° C Decomposition of the complex 70 ° C Current density 1000 A / m 2 Distance electrodes / membrane 2 mm Overflow speed > 10 cm / s pH anolyte 10.5 - 11.5 membrane Neosepta® AMH, manufacturer Tokuyama Soda

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Oxygen, Ozone, And Oxides In General (AREA)

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• 1994
  • 1994-05-24 DE DE4418067A patent/DE4418067C1/de not_active Expired - Fee Related
• 1995
  • 1995-05-11 ES ES95107172T patent/ES2120106T3/es not_active Expired - Lifetime
  • 1995-05-11 EP EP95107172A patent/EP0684324B1/de not_active Expired - Lifetime
  • 1995-05-11 AT AT95107172T patent/ATE170936T1/de not_active IP Right Cessation
  • 1995-05-11 DE DE59503494T patent/DE59503494D1/de not_active Expired - Fee Related
  • 1995-05-18 JP JP7142381A patent/JPH0841668A/ja active Pending
  • 1995-05-19 CA CA002149857A patent/CA2149857A1/en not_active Abandoned
  • 1995-05-22 FI FI952484A patent/FI952484A/fi unknown
  • 1995-05-23 KR KR1019950012834A patent/KR950032715A/ko not_active Application Discontinuation
  • 1995-05-23 NO NO952035A patent/NO309332B1/no not_active IP Right Cessation
  • 1995-05-23 RU RU95108225/28A patent/RU2153538C2/ru active
  • 1995-05-23 TW TW084105118A patent/TW396212B/zh not_active IP Right Cessation
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