CA2149857A1 - Process for the preparation of metal hydroxide - Google Patents
Process for the preparation of metal hydroxideInfo
- Publication number
- CA2149857A1 CA2149857A1 CA002149857A CA2149857A CA2149857A1 CA 2149857 A1 CA2149857 A1 CA 2149857A1 CA 002149857 A CA002149857 A CA 002149857A CA 2149857 A CA2149857 A CA 2149857A CA 2149857 A1 CA2149857 A1 CA 2149857A1
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- metal
- process according
- hydroxide
- ions
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- 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
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- 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
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- 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
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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)
Abstract
Process for the preparation of metal hydroxides and/or metal oxides/hydroxides from corresponding metal ions and hydroxide ions, whereby the metal ions are formed in an electrochemical membrane process in which the metal ions are formed by anodic dissolution of corresponding metals in the anode compartment and the hydroxide ions by cathodic reduction of water in the cathode compartmentseparated by an anion-exchange membrane, and the hydroxide ions are transferred through the anion-exchange membrane into the anode compartment under the driving force of an electric field.
Description
- 21~9857 St-klu-63 8-PE
A process for the preparation of metal hydroxide BACKGROUND OF THE INVENTION
The present invention relates to a process for the preparation of metal hydroxides 5 and/or metal oxidesthydroxides from co~ pollding metal ions and hydroxide ions, in which the metal ions are formed in an electrochemical membrane process by anodic dissolution of corresponding metals in the anode col,lp~llnent and the hydroxide ions by cathodic reduction of water in the cathode compartment bounded by an anion-exchange membrane, and the hydroxide ions are transferred 10 through the anion-exchange membrane into the anode compartment under the driving force of an electric field.
Metal hydroxides and metal oxides/hydroxides are valuable intermediates for the plepal~lion of inorganic or organic salts of said metals, for the corresponding oxides, or the pure metals themselves. For example, a cobalt oxide of defined 15 composition e.g. for use in electronics for the production of varistors or inbatteries, may be plepaled from cobalt hydroxide by calcining or, by reduction, a cobalt metal powder of defined particle size distribution. Nickel hydroxides areused as pigments or are used with various dopants and particle structures for use in batteries. Zinc hydroxides may be used as starting materials for pigments and20 the copper compounds can be converted into catalytically active m~t~ri~l.c.
During the prepdl~ion of hydroxides for various applications, the primary aim isto prepare, if possible, compact and free-flowing m~t~ri~l for further processing Cobalt metal powder, prepared from cobalt hydroxide or cobalt oxide/hydroxide, yields a particle size distribution and particle structure such that it can be sintered 25 together with t~lng~ten carbide to produce products such as, e.g. special carbide-tipped structures.
STA 91-Forei~n Countries - 1 -2149 8ra7 For the newly developed foam anodes which are used particularly in nickel hydride storage cells, a nickel hydroxide is required the physical properties ofwhich are optimized both in terms of the application and the processing technique used. Use in high-performance batteries with nickel foam electrodes (based on 5 paste technology) requires a m~t~ri~l with good flow properties, a compact particle form, narrow particle size distribution and consistent quality. Moreover, the product should have the ability to mix readily with the conventionally used additives such as, e.g., cobalt metal powder and cobalt oxide.
A corresponding m~t~riAI and main features of the production process are described in Japanese patent Hei 4-80513. Nickel hydroxide particles with a diameter between 1 and 100 ~lm are cryst~lli7ed through a nickel salt solution and an alkali hydroxide, in solid or liquid form, being introduced contin--ously into a reaction vessel at a constant pH and a constant temperature. A pH of 11 and a temperature of 48 C are given as favorable test conditions.
15 It is also known that the pr~p~Lion of a sufficiently compact nickel hydroxide may be carried out by precipitation in the presence of ammonia or an ammonium salt. According to Trans. Faraday Soc. 51 (1955) 961, a nickel amine complex solution is plepared from nickel nitrate and aqueous ammonia solution, from which a nickel hydroxide is obtained by boiling at cllstom~ry or reduced pressure 20 or by treatment with steam. Such a hydroxide has a much lower specific surface area (13 to 20 m2/g) compared with the nickel hydroxides that are precipitated in the absence of ammonia. The prepa~Lion of compact nickel hydroxides in the presence of ammonia or an ammonium salt is also disclosed by the Japanese patent applications A 53 6119 and A 61-18107. In the first patent application 25 mentioned, the precipitation of nickel hydroxide by the addition of an alkaline solution to a corresponding solution with a pH of at least 3.0 is described.
Electrochemical tests on the material prepared in this way revealed particularlyhigh specific charge capacities compared with commercial nickel hydroxides.
STA 91-Forei~n Countries - 2 -Such products do not yet, however, fulfill the above-mentioned requirements in terms of particle form, particle size distribution and flow properties.
Important features of the process for the prepalalion of a compact nickel hydroxide and the use thereof in alkaline batteries are described in European patent application A 353 837. A nickel (II)-tetrammine salt solution is preparedby dissolution of nickel nitrate or nickel sulfate in dilute ammonia solution and decomposed by controlled addition of sodium hydroxide solution in accordance with the following reaction:
(1) Ni(NH3)4SO4 + 2 NaOH --> Ni(OH)2 + Na2SO4 + 4 NH3 The reaction takes place at tempel~ures between 40 and 50 C and in the pH
range between 11 and 13. The pore volume falls as the pH falls. It has been ascertained that a pore-free product may be cryst~lli7ed only at sufficiently low rates of reaction. Moreover, the nickel hydroxide prepared according to said process has a high cr,vstallinity, a low specific surface area, a low pore volume and therefore a high physical density. The disadvantages of said product, which are attributable to the high density, are also described. The low specific surface area results in a lower proton conductivity and in a higher current density which promotes the production of ullwanled ~-NiOOH, which leads to swelling of the electrode. Although the nickel hydroxide crystallised at low pH values has a high densit,v, it has a greater tendency to form ~-NiOOH. Due to the choice of a meanpH, a compromise may be found between the required high density and the porosity required to a certain extent. According to said process, a nickel hydroxide is prepared which contains 3 to 10% of zinc and 1 to 3% of magnesium in solid solution. Said dopants counteract the production of ~-NiOOH.
A continuous process for the cryst~lli7~tion of a nickel hydroxide with spherical particle form is implied from the patent JP Hei 4-68249. In said process, a nickel salt solution (0.5 to 3.5 mole/l), dilute alkaline solution (1.25 to 10 mole/l) and an ammonia and/or ammonium salt solution are pumped continuously by means of STA 91-Forei~n Countries - 3 -- 2149~S7 metering pumps, with intensive stirring, into a heated cylindrical container provided with an overflow pipe, it also being possible for the ammonia to be introduced in gaseous form. The ammonia concentration is given as 10 to 28% by wt. and the ammonium salt concentration as 3 to 7.5 mole/l. In order to complex the nickel, between 0.1 and 1.5 mole of ammonia per mole of nickel salt solutionare introduced. After about 10 to 30 hours, the system reaches a stationary state, after which a product with consistent quality may be removed contimlol~ly. The residence time in the container is between 0.5 and 5 hours.
An important feature of said process is the fact that the reaction is carried out at a defined pH which is kept constant to + 0.1 pH levels in the region between 9 and12 by the pH-controlled introduction of alkaline solution, and at a constant temperature in the region between 20 and 80 C, whereby the temperature deviations should not be more than + 2 K. Under these conditions, the compact spherical particles are obtained with a particle size of between 2 and 50 ~lm. The particle size can be adjusted in particular by varying the NH3 inflow, the residence time and the stirring speed. As the stirring speed decreases and the NH3 inflow increases, the particle size increases. As the residence time in the container increases, the product becomes coarser, the particle size distribution nallower.The crystalline product is then filtered, washed with water and dried. The product prepared according to said process has the properties mentioned at the beginningand does not need to be ground.
A process for the preparation of nickel hydroxide is disclosed in European patent application A 462 889. The temperature range of cryst~ tion is above 80 C.
Nitrate or sulphate solutions doped with cobalt, cadmium and/or zinc are used.
The cobalt content is between 1 and 8% by wt., and the contents of cadmium and/or zinc are between 3 and 10% by wt. Complexing takes place with the aid of an ammonium salt, the molar ratio of NH3/Ni being between 0.3 and 0.6. In said process, a pH of 9.2 + 0.1 is maintained. Moreover, a three-blade stirrer, the diameter of which is half as great as the diameter of the container and the rate of rotation of which is between 300 and 1000 min~l is used.
STA 91-Forei~n Countries - 4 -214~8~7 As in the processes already described, the product is filtered, washed and dried.
The disadvantages of said processes are, on the one hand, the large quantities of neutral salts inevitably produced, which are at least twice the stoichiometric quantity of nickel hydroxide and are released into the effluent. On the other hand, 5 the effluents of these processes contain, in addition to small quantities of nickel dissolved in the form of complexes, large quantities of ammonia which must be disposed of.
In the chemical process of precipitation cryst~lli7~tion for the plep~lion of spherical nickel hydroxide, 2 mole of sodium chloride per mole of nickel 10 hydroxide are inevitably produced. In view of more stringent environmental guidelines and limits for effluent, on the one hand, and economic considerationsdue to the high consumption of liquor and resulting landfill costs for the salt produced, on the other hand, closed production circuits must be developed.
In such a process, nickel, for example, is dissolved anodically in a metal salt 15 solution by electrolysis, and precipitated as nickel hydroxide by the cathodically formed hydroxide ions. After sedimentation and various sl1cces.~ive washing stages to purify the precipitated product of any salts still present or entrapped during precipitation, the pure product is obtained.
Processes for the preparation of metal hydroxides are already described in the 20 following patents.
In Japanese patent application A 63/247 385, the electrolytic prep~lion of metalhydroxides is carried out using a perfluorinated anion-exchange membrane of Toyo Soda and the use of inert electrodes. The metal salt of the metal hydroxideto be prepared is used as the electrolyte on the anode side. In the cathode circuit, 25 an alkaline solution is used.
STA 91-Forei~n Countries - 5 -~ 2149857 In European patent application A 0 559 590, in a comparable arrangement, the metal salt is added continuously by anodic dissolution of the electrode. The requirements regarding the process, particularly the membranes to be used, the electrolyte solutions and the test conditions are specified only insufficiently.
5 The object of this invention is to provide a process for the prepal~ion of metal hydroxides and/or metal oxides/hydroxides which does not have the disadvantages of the prior art described.
SIJMMARY OF THE rNVENTION
This object is achieved by a process for the plep~lion of metal hydroxides and/or 10 metal oxides/hydroxides from corresponding metal ions and hydroxide ions, whereby the metal ions are formed in an electrochemical membrane process by anodic dissolution of corresponding metals in the anode compartment and the hydroxide ions by cathodic reduction of water in the cathode compartment bounded by an anion-exchange membrane, and the hydroxide ions are transferred 15 through the anion-exchange membrane into the anode compartment by the drivingforce of an electric field, whereby the dissolution of the metals is carried out in the presence of complexing agent at a pH of >7.
Preferably ammonia and/or organic mono- and/or diamines with a chain length of 1 to 6 C atoms are used as complexing agents within the meaning of this 20 invention. Metals are, in particular, one or more from the group Co, Ni, Cu, Fe, In, Mn, Sn, Zn, Zr, Ti, Al, Cd and Ni. Co and/or Ni are particularly preferred.
The process according to the invention will be described hereinafter for the case of the preparation of nickel hydroxide without thereby restricting the invention.
The configuration arising in principle for a membrane electrolytic cell which is25 suitable for carrying out the process according to the invention is presented below.
The cathode compartment and anode compartment of the electrolytic cell are separated by an anion-exchange membrane such that two separate circuits are STA 91-Forei~n Countries - 6 -~ ~498~7 produced. The circuit on the side of the cathode is called the catholyte and that on the anode side the anolyte. Alkaline solutions such as preferably sodium hydroxide solution or potassium hydroxide solution are used as catholyte. It is advantageous for the efficiency of the process if the solution itself has a high5 conductivity and the cation of the alkaline solution used is also used on the anode side. The cathode itself may be composed of quenched and tempered steel, pl?~tini7ed titanium, nickel, or a nickel alloy.
The composition of the anolyte is obtained from the starting products for the prepal~lion of nickel hydroxide, i.e. ammonia, sodium chloride and small 10 quantities of nickel sulfate. The sodium chloride is used primarily to increase the conductivity of the solution, and the anodic dissolution of the nickel electrode is improved by the small addition of sulphate. Particularly good results are obtained when chloride and/or sulfate ions are present in the anolyte. The anode itself is composed of pure nickel, preferably an electrochemically produced anode.
15 In the preparation of other metal hydroxides and/or metal oxide/hydroxides, the anode is composed of the corresponding metals. In principle, therefore, a sacrificial anode is used.
Under active transport conditions in view of the extf~rn~l potential applied, nickel dissolves as Ni2+ ion, releasing electrons. The presence of ammonia pr~venls the20 spontaneous precipitation of Ni(OH)2 under alkaline conditions and leads via various intermediate stages to a divalent nickel-amine complex.
Anode: (2) Ni + nNH3 + 2 Cl- ~ Ni (NH3)nC12 + 2e~
(3) Ni(NH3)nCl2 + 20H- ~ Ni(OH)2~l n NH3 1` + 2 Cl-Cathode: (4) 2 H20 + 2 e~ ~ H2 1` + 2 OH-(5) Ni + 2H20 ~ H2 1` + NI (OH) STA 91-Foreign Countries - 7 -21498~7 The reaction at the cathode yields hydrogen, with electron uptake, which escapesin gaseous form, and hydroxide ions which are transported in accordance with their charge via the anion-exchange membrane into the anode circuit. The formation and precipitation of the nickel hydroxide then takes place in the anolyte 5 when the solubility limit is exceeded. Precipitation follows a dynamic equilibrium, ligand exchange (ammonia for hydroxide) taking place.
The formation of the spherical product is detennined essentially by the cryst~ tion conditions, i.e. the concentration of the individual components and the temperature control in the anode circuit. The precipitated product is then 10 separated continuously from the anolyte circuit. Separation may be carried out in a sedimentation tank that is simple to design from a process technology angle inview of the great difference in density between the product formed and the solvent. Separation takes place via a filkation stage (microfiltration) in order to sep6l~le a product of uniform particle size. The essential advantage of said 15 process variant is that additional individual process stages for rec~ ve,ing the various starting products are not required since they are kept in the anolyte circuit.
In order to put into practice the electrochemical membrane process described, it is necessary to ensure that the anion-exchange membrane to be used fulfils the following requirements:
20 It must be resistant to alkalis, in particular, chemically stable in the adjacent solutions (to NH3 Up to the saturation concentration), resistant to oxidation (Ni2+/Ni3+; Cl-, Cl03-), temperature-resistant up to 80 C, it must have a high permselectivity, a low membrane resistance, high mechanical strength and dimensional stability and sufficient long-term stability.
25 Industrially relevant ion exchange membranes usually have a microheterogeneous and/or interpolymer morphology. The aim to be achieved thereby is that the mechanical and electrochemical properties may be membranes adjusted in isolation. Accordingly, a membrane is constructed from a matrix polymer, a STA 91-Forei~n Countries - 8 -fabric or a binder, and from a polyelectrolyte or an ionomer. A distinction is made among homogeneous membranes, interpolymer membranes, microhetero-geneous graft or block copolymer membranes and heterogeneous membranes according to the degree of heterogeneity of the ion exchange membrane.
5 The polymer network may have a different structure in order to exhlbit sufficiently good electrical and mechanical properties for most applications. Polyvinyl chloride and polyacrylate is normally used as the electrically neutral matrix polymer. Polyethylene, polyl.ropylene or polysulphone may be used as other matrix polymers, only these having long-term chemical stability under alkaline 10 conditions.
In the process according to the invention, therefore, an anion-exchange membraneis preferably based on polyethylene, poly~lopylene, polyether ketone, poly-sulphone, polyphenyloxide and/or sulfide.
The ion-conducting polyelectrolytes of an anion-exchange membrane are 15 composed of a network with a positive excess charge and mobile, nega~vely charged counterions. The fixed ion structure may be built up by weakly basic amino and imino groups, and from strongly basic ammonium and qu~t~ ry ammon1um groups:
-NH3+ -RNH2 -R3N+ =R2N
20 It is particularly preferred that the anion-exchange membrane used in the process of the invention have exchange groups of alkylated polyvinyl imidazole, polyvinyl pryidine and/or alkylated 1,4-diazabicyclo[2.2.2]octane.
Particularly suitable membranes are described in German patent application A 42 1 1 266.
STA 91-Forei~n Countries - 9 -21~98~7 The type and concentration of fixed ions determines mainly the permselectivity and the electrical resistance of the membrane, but it may also influence the mechanical properties, particularly the swelling of the membrane in view of the concentration of fixed ions. The strongly basic q~1~t~rn~ry ammonium group is 5 dissociated at all pH values, while the primary ammonium group is dissociated only with difficulty. For this reason, mostly q l~tern~ry ammonium groups are incorporated in commercial anion-exchange membranes except if a membrane with particular properties is to be produced.
Systems based on chloromethylated poly~lylene, styrene/divinylbenzene 10 copolymers and styrene/butadiene copolymers with subsequent qu~tern~ tion with trimethylamine are used most frequently.
The long-term chemical stability of the anion-exchange membranes may be influenced only by the following factors:
- destruction of the polymer matrix (inadequate stability of the matrix polymer or interpolymer in alkaline solution) - morphological change of the fixed ion structure/polymer matrix system - chemical degradation of the fixed ion under alkaline or oxidative conditions.
The electrochemical, mechanical and chemical properties must be optimized in the20 same way for the selection of an anion-exchange membrane for use in the preparation of spherical nickel hydroxide by membrane electrolysis from ammoniacal solution. This means that requirements in terms of membrane and material selection and the physico-chemical properties produced by the manufacturer must be drawn up and evaluated. Said requirements may be 25 summarized as follows for the membranes used according to the invention:
ST~ 91-Forei~n Countries - 10 -21498~7 -As regards the electrochemical properties, the electrical resistance should be <10 Q. cm2 the perrnselectivity >92%
the swelling <25%, and S the ion exchange capacity >1.2 mmole.g-l.
As regards the mechanical properties, the fabric should be composed of temperature-, alkali- and oxidation-resistant polymers (polyplu~ylene, polyethylene, polyether ketone) and have, as a fixed loading chemically stable ql1~tprn~ry ammonium salt (vinyl imidazole, 4.4'-diazabicyclo[2.2.2]octane).
Suitable membranes are described in German patent application 44 21 1266. It is particularly preferred that the process according to the invention be carried out continuously, the metal hydroxide and/or metal oxide/hydroxide formed being 15 separated from the anolyte and the complexing agent being returned to the anode compartment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The invention is explained by way of example below, without any restriction being implied therein.
STA 91-Foreign Countries - 11 -21~9857 Example 1 Preparation of cobalt hydroxides Structure of the electrolytic cell in principle The electrolytic cell is shown in attached Fig. 1. It is composed of two nickel cathodes, two polyethylene spacers, two membranes and the cobalt sacrificial anode and four compartments of varying thickness. The cell is constructed in such a way that the nickel cathodes represent the outer sides of the cell with asurface area of 120 x 200 mm2 of effective electrode surface. The electrical contacting takes place on superimposed electrode surfaces. On the cathode lies apolyethylene frame 5 mm thick on which in turn the membrane lies. The gap between the membrane and the cobalt anode is m~int~ined by a further frame 10 mm thick, which anode lies above the frame and is provided with the electrical leads. The cobalt anode is composed of pure cobalt with a thickness of 20 mm.
The entire structure is pressed together in a liquid-tight manner by means of a support. A polyethylene lattice core mesh is inserted between the cathode and the membrane, which lattice prevents contact between cathode and membrane. The frames that separate anode and membrane are provided with holes through which the anolyte enters and leaves. The cathodes are similarly provided with inlets at the cathode-membrane separating frames such that a uniform flow with the catholyte is guaranteed in the entire cathode compartment.
The catholyte and anolyte each contain 100 g/l of NaCl. The catholyte also contains 40 g/l NaOH.
The catholyte is pumped round (recirculated) at a speed of 100 l/h, which corresponds to a residence time of the electrolyte of 9 seconds in the cathode compartment. The anolyte is pumped in a recirculating circuit during electrolysis - 25 at a rate of 650 l/h 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 mole/l and losses by evaporation are offset by the addition of ammonia to the anolyte circuit.
STA 91-Forei~n Countries - 12 -21198~7 -The stationary solids concentration of cobalt hydroxides formed is 80 g/l with an average residence time of 4 h.
The electrolysis conditions are chosen such that a current of 12 A correspondingto 500 A/m2 flows, whereby 21 g of cobalt hydroxide in the form of Co(OH)2 are 5 formed each hour, which are expelled from the circuit in a 0.261 suspension and separated by filtration. After washing with water, a clean cobalt hydroxide is obtained. The hydrogen formed is expelled from the catholyte storage container.
pH anolyte: 10.5-11.5 Membrane: Neosepta~ AMH, m~mlf~c~lred by Tokuyama Soda 10 Composition of the end product:
Cobalt hydroxide, mixture of Co(OH)2 with CoOOH in a ratio of 80/20 according to analysis.
Bulk density: 1.6 g/cm3 Cobalt content: 63.5%
15 Color: Dark brown.
Example 2 Plepal~ion of nickel hydroxide In an electrolytic cell which is constructed in a comparable way (as in Example 1) as a stack of electrodes and membranes with the electrode compartments in between, nickel is dissolved electrochemically in the presence of ammonia, and 20 the amine complex formed decomposes to nickel hydroxide.
Electrolyte composition:
Anolyte: 16.5 mole/l NiSO4 220 ml NH3 (25%)/1 STA 91-Forei~n Countries - 13 -21498~7 2 mole/l NaCl Catholyte: 1 mole/l NaOH
Anode: Ultra-pure nickel Cathode: Pl~tini7ed titanium Temperature: Electrolysis 40 C
Decomposition of the complex 70 C
Current density: 1000 A/m2 Gap between electrode/membrane: 2 mm Overflow speed: >10 cm/s pH anolyte: 10.5-11.5 Membrane: Neosepta~) AMH manufactured by Tokuyama Soda The decomposition of the amine complex formed in electrolysis to nickel hydroxide is carried out by raising the telllpel~lult; of the electrolyte in a reactor.
a) Preparation of a compact, spherical nickel hydroxide The amine complex is decomposed in a stirred reactor whereby the decomposition product agglomerates to compact, spherical particles. The agglomerated m~tP.ri~l is sepal~ted continuously as a suspension from the circuit of the anolyte via an overflow.
Nickel hydroxide from the overflow:
Bulk density: 1.35 g/cm3 Mean particle size: 10 ~lm b) In the presence of substrates such as fibers of nickel or a spherical ion exchange resin with the mean particle size of 200 ,um, a uniform layer of nickel hydroxide is deposited on the substrate in the decomposition reactor.
STA 91-Foreign Countries - 14 -
A process for the preparation of metal hydroxide BACKGROUND OF THE INVENTION
The present invention relates to a process for the preparation of metal hydroxides 5 and/or metal oxidesthydroxides from co~ pollding metal ions and hydroxide ions, in which the metal ions are formed in an electrochemical membrane process by anodic dissolution of corresponding metals in the anode col,lp~llnent and the hydroxide ions by cathodic reduction of water in the cathode compartment bounded by an anion-exchange membrane, and the hydroxide ions are transferred 10 through the anion-exchange membrane into the anode compartment under the driving force of an electric field.
Metal hydroxides and metal oxides/hydroxides are valuable intermediates for the plepal~lion of inorganic or organic salts of said metals, for the corresponding oxides, or the pure metals themselves. For example, a cobalt oxide of defined 15 composition e.g. for use in electronics for the production of varistors or inbatteries, may be plepaled from cobalt hydroxide by calcining or, by reduction, a cobalt metal powder of defined particle size distribution. Nickel hydroxides areused as pigments or are used with various dopants and particle structures for use in batteries. Zinc hydroxides may be used as starting materials for pigments and20 the copper compounds can be converted into catalytically active m~t~ri~l.c.
During the prepdl~ion of hydroxides for various applications, the primary aim isto prepare, if possible, compact and free-flowing m~t~ri~l for further processing Cobalt metal powder, prepared from cobalt hydroxide or cobalt oxide/hydroxide, yields a particle size distribution and particle structure such that it can be sintered 25 together with t~lng~ten carbide to produce products such as, e.g. special carbide-tipped structures.
STA 91-Forei~n Countries - 1 -2149 8ra7 For the newly developed foam anodes which are used particularly in nickel hydride storage cells, a nickel hydroxide is required the physical properties ofwhich are optimized both in terms of the application and the processing technique used. Use in high-performance batteries with nickel foam electrodes (based on 5 paste technology) requires a m~t~ri~l with good flow properties, a compact particle form, narrow particle size distribution and consistent quality. Moreover, the product should have the ability to mix readily with the conventionally used additives such as, e.g., cobalt metal powder and cobalt oxide.
A corresponding m~t~riAI and main features of the production process are described in Japanese patent Hei 4-80513. Nickel hydroxide particles with a diameter between 1 and 100 ~lm are cryst~lli7ed through a nickel salt solution and an alkali hydroxide, in solid or liquid form, being introduced contin--ously into a reaction vessel at a constant pH and a constant temperature. A pH of 11 and a temperature of 48 C are given as favorable test conditions.
15 It is also known that the pr~p~Lion of a sufficiently compact nickel hydroxide may be carried out by precipitation in the presence of ammonia or an ammonium salt. According to Trans. Faraday Soc. 51 (1955) 961, a nickel amine complex solution is plepared from nickel nitrate and aqueous ammonia solution, from which a nickel hydroxide is obtained by boiling at cllstom~ry or reduced pressure 20 or by treatment with steam. Such a hydroxide has a much lower specific surface area (13 to 20 m2/g) compared with the nickel hydroxides that are precipitated in the absence of ammonia. The prepa~Lion of compact nickel hydroxides in the presence of ammonia or an ammonium salt is also disclosed by the Japanese patent applications A 53 6119 and A 61-18107. In the first patent application 25 mentioned, the precipitation of nickel hydroxide by the addition of an alkaline solution to a corresponding solution with a pH of at least 3.0 is described.
Electrochemical tests on the material prepared in this way revealed particularlyhigh specific charge capacities compared with commercial nickel hydroxides.
STA 91-Forei~n Countries - 2 -Such products do not yet, however, fulfill the above-mentioned requirements in terms of particle form, particle size distribution and flow properties.
Important features of the process for the prepalalion of a compact nickel hydroxide and the use thereof in alkaline batteries are described in European patent application A 353 837. A nickel (II)-tetrammine salt solution is preparedby dissolution of nickel nitrate or nickel sulfate in dilute ammonia solution and decomposed by controlled addition of sodium hydroxide solution in accordance with the following reaction:
(1) Ni(NH3)4SO4 + 2 NaOH --> Ni(OH)2 + Na2SO4 + 4 NH3 The reaction takes place at tempel~ures between 40 and 50 C and in the pH
range between 11 and 13. The pore volume falls as the pH falls. It has been ascertained that a pore-free product may be cryst~lli7ed only at sufficiently low rates of reaction. Moreover, the nickel hydroxide prepared according to said process has a high cr,vstallinity, a low specific surface area, a low pore volume and therefore a high physical density. The disadvantages of said product, which are attributable to the high density, are also described. The low specific surface area results in a lower proton conductivity and in a higher current density which promotes the production of ullwanled ~-NiOOH, which leads to swelling of the electrode. Although the nickel hydroxide crystallised at low pH values has a high densit,v, it has a greater tendency to form ~-NiOOH. Due to the choice of a meanpH, a compromise may be found between the required high density and the porosity required to a certain extent. According to said process, a nickel hydroxide is prepared which contains 3 to 10% of zinc and 1 to 3% of magnesium in solid solution. Said dopants counteract the production of ~-NiOOH.
A continuous process for the cryst~lli7~tion of a nickel hydroxide with spherical particle form is implied from the patent JP Hei 4-68249. In said process, a nickel salt solution (0.5 to 3.5 mole/l), dilute alkaline solution (1.25 to 10 mole/l) and an ammonia and/or ammonium salt solution are pumped continuously by means of STA 91-Forei~n Countries - 3 -- 2149~S7 metering pumps, with intensive stirring, into a heated cylindrical container provided with an overflow pipe, it also being possible for the ammonia to be introduced in gaseous form. The ammonia concentration is given as 10 to 28% by wt. and the ammonium salt concentration as 3 to 7.5 mole/l. In order to complex the nickel, between 0.1 and 1.5 mole of ammonia per mole of nickel salt solutionare introduced. After about 10 to 30 hours, the system reaches a stationary state, after which a product with consistent quality may be removed contimlol~ly. The residence time in the container is between 0.5 and 5 hours.
An important feature of said process is the fact that the reaction is carried out at a defined pH which is kept constant to + 0.1 pH levels in the region between 9 and12 by the pH-controlled introduction of alkaline solution, and at a constant temperature in the region between 20 and 80 C, whereby the temperature deviations should not be more than + 2 K. Under these conditions, the compact spherical particles are obtained with a particle size of between 2 and 50 ~lm. The particle size can be adjusted in particular by varying the NH3 inflow, the residence time and the stirring speed. As the stirring speed decreases and the NH3 inflow increases, the particle size increases. As the residence time in the container increases, the product becomes coarser, the particle size distribution nallower.The crystalline product is then filtered, washed with water and dried. The product prepared according to said process has the properties mentioned at the beginningand does not need to be ground.
A process for the preparation of nickel hydroxide is disclosed in European patent application A 462 889. The temperature range of cryst~ tion is above 80 C.
Nitrate or sulphate solutions doped with cobalt, cadmium and/or zinc are used.
The cobalt content is between 1 and 8% by wt., and the contents of cadmium and/or zinc are between 3 and 10% by wt. Complexing takes place with the aid of an ammonium salt, the molar ratio of NH3/Ni being between 0.3 and 0.6. In said process, a pH of 9.2 + 0.1 is maintained. Moreover, a three-blade stirrer, the diameter of which is half as great as the diameter of the container and the rate of rotation of which is between 300 and 1000 min~l is used.
STA 91-Forei~n Countries - 4 -214~8~7 As in the processes already described, the product is filtered, washed and dried.
The disadvantages of said processes are, on the one hand, the large quantities of neutral salts inevitably produced, which are at least twice the stoichiometric quantity of nickel hydroxide and are released into the effluent. On the other hand, 5 the effluents of these processes contain, in addition to small quantities of nickel dissolved in the form of complexes, large quantities of ammonia which must be disposed of.
In the chemical process of precipitation cryst~lli7~tion for the plep~lion of spherical nickel hydroxide, 2 mole of sodium chloride per mole of nickel 10 hydroxide are inevitably produced. In view of more stringent environmental guidelines and limits for effluent, on the one hand, and economic considerationsdue to the high consumption of liquor and resulting landfill costs for the salt produced, on the other hand, closed production circuits must be developed.
In such a process, nickel, for example, is dissolved anodically in a metal salt 15 solution by electrolysis, and precipitated as nickel hydroxide by the cathodically formed hydroxide ions. After sedimentation and various sl1cces.~ive washing stages to purify the precipitated product of any salts still present or entrapped during precipitation, the pure product is obtained.
Processes for the preparation of metal hydroxides are already described in the 20 following patents.
In Japanese patent application A 63/247 385, the electrolytic prep~lion of metalhydroxides is carried out using a perfluorinated anion-exchange membrane of Toyo Soda and the use of inert electrodes. The metal salt of the metal hydroxideto be prepared is used as the electrolyte on the anode side. In the cathode circuit, 25 an alkaline solution is used.
STA 91-Forei~n Countries - 5 -~ 2149857 In European patent application A 0 559 590, in a comparable arrangement, the metal salt is added continuously by anodic dissolution of the electrode. The requirements regarding the process, particularly the membranes to be used, the electrolyte solutions and the test conditions are specified only insufficiently.
5 The object of this invention is to provide a process for the prepal~ion of metal hydroxides and/or metal oxides/hydroxides which does not have the disadvantages of the prior art described.
SIJMMARY OF THE rNVENTION
This object is achieved by a process for the plep~lion of metal hydroxides and/or 10 metal oxides/hydroxides from corresponding metal ions and hydroxide ions, whereby the metal ions are formed in an electrochemical membrane process by anodic dissolution of corresponding metals in the anode compartment and the hydroxide ions by cathodic reduction of water in the cathode compartment bounded by an anion-exchange membrane, and the hydroxide ions are transferred 15 through the anion-exchange membrane into the anode compartment by the drivingforce of an electric field, whereby the dissolution of the metals is carried out in the presence of complexing agent at a pH of >7.
Preferably ammonia and/or organic mono- and/or diamines with a chain length of 1 to 6 C atoms are used as complexing agents within the meaning of this 20 invention. Metals are, in particular, one or more from the group Co, Ni, Cu, Fe, In, Mn, Sn, Zn, Zr, Ti, Al, Cd and Ni. Co and/or Ni are particularly preferred.
The process according to the invention will be described hereinafter for the case of the preparation of nickel hydroxide without thereby restricting the invention.
The configuration arising in principle for a membrane electrolytic cell which is25 suitable for carrying out the process according to the invention is presented below.
The cathode compartment and anode compartment of the electrolytic cell are separated by an anion-exchange membrane such that two separate circuits are STA 91-Forei~n Countries - 6 -~ ~498~7 produced. The circuit on the side of the cathode is called the catholyte and that on the anode side the anolyte. Alkaline solutions such as preferably sodium hydroxide solution or potassium hydroxide solution are used as catholyte. It is advantageous for the efficiency of the process if the solution itself has a high5 conductivity and the cation of the alkaline solution used is also used on the anode side. The cathode itself may be composed of quenched and tempered steel, pl?~tini7ed titanium, nickel, or a nickel alloy.
The composition of the anolyte is obtained from the starting products for the prepal~lion of nickel hydroxide, i.e. ammonia, sodium chloride and small 10 quantities of nickel sulfate. The sodium chloride is used primarily to increase the conductivity of the solution, and the anodic dissolution of the nickel electrode is improved by the small addition of sulphate. Particularly good results are obtained when chloride and/or sulfate ions are present in the anolyte. The anode itself is composed of pure nickel, preferably an electrochemically produced anode.
15 In the preparation of other metal hydroxides and/or metal oxide/hydroxides, the anode is composed of the corresponding metals. In principle, therefore, a sacrificial anode is used.
Under active transport conditions in view of the extf~rn~l potential applied, nickel dissolves as Ni2+ ion, releasing electrons. The presence of ammonia pr~venls the20 spontaneous precipitation of Ni(OH)2 under alkaline conditions and leads via various intermediate stages to a divalent nickel-amine complex.
Anode: (2) Ni + nNH3 + 2 Cl- ~ Ni (NH3)nC12 + 2e~
(3) Ni(NH3)nCl2 + 20H- ~ Ni(OH)2~l n NH3 1` + 2 Cl-Cathode: (4) 2 H20 + 2 e~ ~ H2 1` + 2 OH-(5) Ni + 2H20 ~ H2 1` + NI (OH) STA 91-Foreign Countries - 7 -21498~7 The reaction at the cathode yields hydrogen, with electron uptake, which escapesin gaseous form, and hydroxide ions which are transported in accordance with their charge via the anion-exchange membrane into the anode circuit. The formation and precipitation of the nickel hydroxide then takes place in the anolyte 5 when the solubility limit is exceeded. Precipitation follows a dynamic equilibrium, ligand exchange (ammonia for hydroxide) taking place.
The formation of the spherical product is detennined essentially by the cryst~ tion conditions, i.e. the concentration of the individual components and the temperature control in the anode circuit. The precipitated product is then 10 separated continuously from the anolyte circuit. Separation may be carried out in a sedimentation tank that is simple to design from a process technology angle inview of the great difference in density between the product formed and the solvent. Separation takes place via a filkation stage (microfiltration) in order to sep6l~le a product of uniform particle size. The essential advantage of said 15 process variant is that additional individual process stages for rec~ ve,ing the various starting products are not required since they are kept in the anolyte circuit.
In order to put into practice the electrochemical membrane process described, it is necessary to ensure that the anion-exchange membrane to be used fulfils the following requirements:
20 It must be resistant to alkalis, in particular, chemically stable in the adjacent solutions (to NH3 Up to the saturation concentration), resistant to oxidation (Ni2+/Ni3+; Cl-, Cl03-), temperature-resistant up to 80 C, it must have a high permselectivity, a low membrane resistance, high mechanical strength and dimensional stability and sufficient long-term stability.
25 Industrially relevant ion exchange membranes usually have a microheterogeneous and/or interpolymer morphology. The aim to be achieved thereby is that the mechanical and electrochemical properties may be membranes adjusted in isolation. Accordingly, a membrane is constructed from a matrix polymer, a STA 91-Forei~n Countries - 8 -fabric or a binder, and from a polyelectrolyte or an ionomer. A distinction is made among homogeneous membranes, interpolymer membranes, microhetero-geneous graft or block copolymer membranes and heterogeneous membranes according to the degree of heterogeneity of the ion exchange membrane.
5 The polymer network may have a different structure in order to exhlbit sufficiently good electrical and mechanical properties for most applications. Polyvinyl chloride and polyacrylate is normally used as the electrically neutral matrix polymer. Polyethylene, polyl.ropylene or polysulphone may be used as other matrix polymers, only these having long-term chemical stability under alkaline 10 conditions.
In the process according to the invention, therefore, an anion-exchange membraneis preferably based on polyethylene, poly~lopylene, polyether ketone, poly-sulphone, polyphenyloxide and/or sulfide.
The ion-conducting polyelectrolytes of an anion-exchange membrane are 15 composed of a network with a positive excess charge and mobile, nega~vely charged counterions. The fixed ion structure may be built up by weakly basic amino and imino groups, and from strongly basic ammonium and qu~t~ ry ammon1um groups:
-NH3+ -RNH2 -R3N+ =R2N
20 It is particularly preferred that the anion-exchange membrane used in the process of the invention have exchange groups of alkylated polyvinyl imidazole, polyvinyl pryidine and/or alkylated 1,4-diazabicyclo[2.2.2]octane.
Particularly suitable membranes are described in German patent application A 42 1 1 266.
STA 91-Forei~n Countries - 9 -21~98~7 The type and concentration of fixed ions determines mainly the permselectivity and the electrical resistance of the membrane, but it may also influence the mechanical properties, particularly the swelling of the membrane in view of the concentration of fixed ions. The strongly basic q~1~t~rn~ry ammonium group is 5 dissociated at all pH values, while the primary ammonium group is dissociated only with difficulty. For this reason, mostly q l~tern~ry ammonium groups are incorporated in commercial anion-exchange membranes except if a membrane with particular properties is to be produced.
Systems based on chloromethylated poly~lylene, styrene/divinylbenzene 10 copolymers and styrene/butadiene copolymers with subsequent qu~tern~ tion with trimethylamine are used most frequently.
The long-term chemical stability of the anion-exchange membranes may be influenced only by the following factors:
- destruction of the polymer matrix (inadequate stability of the matrix polymer or interpolymer in alkaline solution) - morphological change of the fixed ion structure/polymer matrix system - chemical degradation of the fixed ion under alkaline or oxidative conditions.
The electrochemical, mechanical and chemical properties must be optimized in the20 same way for the selection of an anion-exchange membrane for use in the preparation of spherical nickel hydroxide by membrane electrolysis from ammoniacal solution. This means that requirements in terms of membrane and material selection and the physico-chemical properties produced by the manufacturer must be drawn up and evaluated. Said requirements may be 25 summarized as follows for the membranes used according to the invention:
ST~ 91-Forei~n Countries - 10 -21498~7 -As regards the electrochemical properties, the electrical resistance should be <10 Q. cm2 the perrnselectivity >92%
the swelling <25%, and S the ion exchange capacity >1.2 mmole.g-l.
As regards the mechanical properties, the fabric should be composed of temperature-, alkali- and oxidation-resistant polymers (polyplu~ylene, polyethylene, polyether ketone) and have, as a fixed loading chemically stable ql1~tprn~ry ammonium salt (vinyl imidazole, 4.4'-diazabicyclo[2.2.2]octane).
Suitable membranes are described in German patent application 44 21 1266. It is particularly preferred that the process according to the invention be carried out continuously, the metal hydroxide and/or metal oxide/hydroxide formed being 15 separated from the anolyte and the complexing agent being returned to the anode compartment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The invention is explained by way of example below, without any restriction being implied therein.
STA 91-Foreign Countries - 11 -21~9857 Example 1 Preparation of cobalt hydroxides Structure of the electrolytic cell in principle The electrolytic cell is shown in attached Fig. 1. It is composed of two nickel cathodes, two polyethylene spacers, two membranes and the cobalt sacrificial anode and four compartments of varying thickness. The cell is constructed in such a way that the nickel cathodes represent the outer sides of the cell with asurface area of 120 x 200 mm2 of effective electrode surface. The electrical contacting takes place on superimposed electrode surfaces. On the cathode lies apolyethylene frame 5 mm thick on which in turn the membrane lies. The gap between the membrane and the cobalt anode is m~int~ined by a further frame 10 mm thick, which anode lies above the frame and is provided with the electrical leads. The cobalt anode is composed of pure cobalt with a thickness of 20 mm.
The entire structure is pressed together in a liquid-tight manner by means of a support. A polyethylene lattice core mesh is inserted between the cathode and the membrane, which lattice prevents contact between cathode and membrane. The frames that separate anode and membrane are provided with holes through which the anolyte enters and leaves. The cathodes are similarly provided with inlets at the cathode-membrane separating frames such that a uniform flow with the catholyte is guaranteed in the entire cathode compartment.
The catholyte and anolyte each contain 100 g/l of NaCl. The catholyte also contains 40 g/l NaOH.
The catholyte is pumped round (recirculated) at a speed of 100 l/h, which corresponds to a residence time of the electrolyte of 9 seconds in the cathode compartment. The anolyte is pumped in a recirculating circuit during electrolysis - 25 at a rate of 650 l/h 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 mole/l and losses by evaporation are offset by the addition of ammonia to the anolyte circuit.
STA 91-Forei~n Countries - 12 -21198~7 -The stationary solids concentration of cobalt hydroxides formed is 80 g/l with an average residence time of 4 h.
The electrolysis conditions are chosen such that a current of 12 A correspondingto 500 A/m2 flows, whereby 21 g of cobalt hydroxide in the form of Co(OH)2 are 5 formed each hour, which are expelled from the circuit in a 0.261 suspension and separated by filtration. After washing with water, a clean cobalt hydroxide is obtained. The hydrogen formed is expelled from the catholyte storage container.
pH anolyte: 10.5-11.5 Membrane: Neosepta~ AMH, m~mlf~c~lred by Tokuyama Soda 10 Composition of the end product:
Cobalt hydroxide, mixture of Co(OH)2 with CoOOH in a ratio of 80/20 according to analysis.
Bulk density: 1.6 g/cm3 Cobalt content: 63.5%
15 Color: Dark brown.
Example 2 Plepal~ion of nickel hydroxide In an electrolytic cell which is constructed in a comparable way (as in Example 1) as a stack of electrodes and membranes with the electrode compartments in between, nickel is dissolved electrochemically in the presence of ammonia, and 20 the amine complex formed decomposes to nickel hydroxide.
Electrolyte composition:
Anolyte: 16.5 mole/l NiSO4 220 ml NH3 (25%)/1 STA 91-Forei~n Countries - 13 -21498~7 2 mole/l NaCl Catholyte: 1 mole/l NaOH
Anode: Ultra-pure nickel Cathode: Pl~tini7ed titanium Temperature: Electrolysis 40 C
Decomposition of the complex 70 C
Current density: 1000 A/m2 Gap between electrode/membrane: 2 mm Overflow speed: >10 cm/s pH anolyte: 10.5-11.5 Membrane: Neosepta~) AMH manufactured by Tokuyama Soda The decomposition of the amine complex formed in electrolysis to nickel hydroxide is carried out by raising the telllpel~lult; of the electrolyte in a reactor.
a) Preparation of a compact, spherical nickel hydroxide The amine complex is decomposed in a stirred reactor whereby the decomposition product agglomerates to compact, spherical particles. The agglomerated m~tP.ri~l is sepal~ted continuously as a suspension from the circuit of the anolyte via an overflow.
Nickel hydroxide from the overflow:
Bulk density: 1.35 g/cm3 Mean particle size: 10 ~lm b) In the presence of substrates such as fibers of nickel or a spherical ion exchange resin with the mean particle size of 200 ,um, a uniform layer of nickel hydroxide is deposited on the substrate in the decomposition reactor.
STA 91-Foreign Countries - 14 -
Claims (11)
1. A process for the preparation of metal hydroxides and/or metal oxides/hydroxides from corresponding metal ions and hydroxide ions, wherein the metal ions are formed in an electrochemical membrane process by anodic dissolution of corresponding metals in the anode compartment and the hydroxide ions by cathodic reduction of water in the cathode compartment bounded by an ion-exchange membrane, and the hydroxide ions are transferred through the ion-exchange membrane into the anode compartment under the driving force of an electric field, characterized in that the dissolution of the metals is carried out in the presence of a complexing agent at a pH greater than 7.
2. Process according to claim 1, wherein the complexing agent is selected from the group consisting of ammonia C1-6- organic monoamines and C1-6- organic diamines.
3. Process according to claim 1, wherein the metal is selected from the group consisting of Co, Ni, Cu, Fe, In, Mn, Sn, Zn, Zr, Ti, Al, Cd and U.
4. Process according to claim 1, wherein the metal is selected from the group consisting of Co and Ni.
5. Process according to claim 1, wherein the catholyte is an aqueous alkaline solution.
6. Process according to claim 1, wherein the anolyte includes chloride or sulphate ions.
7. Process according to claim 4, wherein the anolyte includes chloride sulphate ions.
8. A process according to any one of claims 4, 5 or 6 wherein the complexing agent is selected from the group consisting of ammonia, C1-6- organic monoamines and C1-6-organic diamines, the metal is selected from the group consisting of Co, Ni, Cu, Fe, In, Mn, Sn, Zn, Zr, Ti, Al, Cd and U.
9. A process according to any one of claims 4, 5 or 6 wherein the ion-exchange membrane is a membrane based on a compound selected from the group consisting of polyethylene, polypropylene, polyether ketone, polysulphone, polyphenyloxide and sulphide.
10. A process according to claim 9, wherein the ion-exchange membrane has exchange groups selected from the group consisting of alkylated polyvinyl imidazole, polyvinyl, pyridine and alkylated 1,4-diazabicyclo [2.2.2]octane.
11. A process according to any one of claims 4, 5, or 6 wherein the metal hydroxide and/or metal oxide/hydroxide formed is separated from the anolyte and the complexing agent is returned to the anode compartment.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4418067A DE4418067C1 (en) | 1994-05-24 | 1994-05-24 | Process for the preparation of metal hydroxides and / or metal oxide hydroxides |
| DEP4418067.5 | 1994-05-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2149857A1 true CA2149857A1 (en) | 1995-11-25 |
Family
ID=6518828
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002149857A Abandoned CA2149857A1 (en) | 1994-05-24 | 1995-05-19 | Process for the preparation of metal hydroxide |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0684324B1 (en) |
| JP (1) | JPH0841668A (en) |
| KR (1) | KR950032715A (en) |
| CN (1) | CN1060823C (en) |
| AT (1) | ATE170936T1 (en) |
| CA (1) | CA2149857A1 (en) |
| DE (2) | DE4418067C1 (en) |
| ES (1) | ES2120106T3 (en) |
| FI (1) | FI952484A (en) |
| NO (1) | NO309332B1 (en) |
| RU (1) | RU2153538C2 (en) |
| TW (1) | TW396212B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6752918B1 (en) | 1999-05-07 | 2004-06-22 | H. C. Starck Gmbh | Method for producing nickel hydroxides |
| US7048843B2 (en) | 2000-06-19 | 2006-05-23 | H.C. Starck Gmbh | Method for producing metal hydroxides or alkaline metal carbonates |
| DE102020109690A1 (en) | 2020-04-07 | 2021-10-07 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Selective modification of ion exchange membranes with iridium oxide by pH-controlled precipitation of IrOx species at the phase boundary |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5984982A (en) * | 1997-09-05 | 1999-11-16 | Duracell Inc. | Electrochemical synthesis of cobalt oxyhydroxide |
| JP4593038B2 (en) * | 2001-09-21 | 2010-12-08 | 古河機械金属株式会社 | Method for producing cobalt sulfate solution |
| US8822030B2 (en) | 2006-08-11 | 2014-09-02 | Aqua Resources Corporation | Nanoplatelet metal hydroxides and methods of preparing same |
| US7736485B2 (en) | 2006-08-11 | 2010-06-15 | Aqua Resources Corporation | Nanoplatelet magnesium hydroxides and methods of preparing same |
| CN103184466B (en) * | 2013-01-10 | 2015-06-17 | 昆明贵千新型材料技术研究有限公司 | Novel process for preparing high purity metal oxide |
| CN107190274A (en) * | 2017-05-10 | 2017-09-22 | 东北大学 | A kind of method that nickel chloride electricity conversion directly prepares nickel hydroxide |
| JP7259389B2 (en) * | 2018-05-16 | 2023-04-18 | 住友金属鉱山株式会社 | Method for producing sulfuric acid solution |
| CN110983399A (en) * | 2019-11-29 | 2020-04-10 | 深圳市裕展精密科技有限公司 | Metal product and method for producing metal product |
| CN112877746A (en) * | 2021-01-12 | 2021-06-01 | 北京科技大学 | Method for preparing high-purity lutetium aluminum garnet precursor |
| CN114016048B (en) * | 2021-12-16 | 2023-08-01 | 西北师范大学 | Micro-nano structure Zn (OH) 2 And ZnO controllable preparation method |
| WO2023137553A1 (en) * | 2022-01-20 | 2023-07-27 | The University Of British Columbia | Methods and apparatus for converting metal carbonate salts to metal hydroxides |
| CN115821284A (en) * | 2022-09-29 | 2023-03-21 | 西南医科大学 | Composite catalytic electrode material for promoting hydrogen production by alkaline electrolysis of water by enhancing water dissociation |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS536119B2 (en) * | 1975-01-28 | 1978-03-04 | ||
| GB1600750A (en) * | 1978-05-24 | 1981-10-21 | Assoun C D | Process and apparatus for the production of hydroxides of metallic or semi-conductor elements |
| US4597957A (en) * | 1984-03-06 | 1986-07-01 | Japan Metals And Chemicals Co., Ltd. | Process for electrolytically producing metallic oxide for ferrite |
| JPS63206487A (en) * | 1987-02-23 | 1988-08-25 | Tosoh Corp | Production of metallic hydroxide by electrolysis |
| JPS63247385A (en) * | 1987-04-03 | 1988-10-14 | Tosoh Corp | Production of metallic hydroxide |
| DE68917045T2 (en) * | 1988-07-19 | 1995-03-16 | Yuasa Battery Co Ltd | Nickel electrode for an alkaline battery. |
| ES2066385T3 (en) * | 1990-06-18 | 1995-03-01 | Accumulateurs Fixes | PREPARATION PROCEDURE FOR A METALLIC HYDROXIDE POWDER AND POWDER OBTAINED BY THIS PROCEDURE. |
| US5135622A (en) * | 1991-12-02 | 1992-08-04 | At&T Bell Laboratories | Electrochemical synthesis of palladium hydroxide compounds |
| FR2688235B1 (en) * | 1992-03-05 | 1995-06-23 | Sorapec | PROCESS FOR OBTAINING METAL HYDROXIDES. |
| DE4211266C2 (en) * | 1992-04-03 | 1996-12-19 | Fraunhofer Ges Forschung | Non-porous, flat or fibrous polymer structures with a hydrophilic surface and their use as membranes for dialysis or electrodialysis |
| JP2819488B2 (en) * | 1992-10-06 | 1998-10-30 | 日本電信電話株式会社 | Method for manufacturing electric field sensor |
-
1994
- 1994-05-24 DE DE4418067A patent/DE4418067C1/en not_active Expired - Fee Related
-
1995
- 1995-05-11 EP EP95107172A patent/EP0684324B1/en not_active Expired - Lifetime
- 1995-05-11 AT AT95107172T patent/ATE170936T1/en not_active IP Right Cessation
- 1995-05-11 ES ES95107172T patent/ES2120106T3/en not_active Expired - Lifetime
- 1995-05-11 DE DE59503494T patent/DE59503494D1/en not_active Expired - Fee Related
- 1995-05-18 JP JP7142381A patent/JPH0841668A/en active Pending
- 1995-05-19 CA CA002149857A patent/CA2149857A1/en not_active Abandoned
- 1995-05-22 FI FI952484A patent/FI952484A/en unknown
- 1995-05-23 TW TW084105118A patent/TW396212B/en not_active IP Right Cessation
- 1995-05-23 NO NO952035A patent/NO309332B1/en not_active IP Right Cessation
- 1995-05-23 RU RU95108225/28A patent/RU2153538C2/en active
- 1995-05-23 KR KR1019950012834A patent/KR950032715A/en not_active Application Discontinuation
- 1995-05-23 CN CN95106681A patent/CN1060823C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6752918B1 (en) | 1999-05-07 | 2004-06-22 | H. C. Starck Gmbh | Method for producing nickel hydroxides |
| US7048843B2 (en) | 2000-06-19 | 2006-05-23 | H.C. Starck Gmbh | Method for producing metal hydroxides or alkaline metal carbonates |
| DE102020109690A1 (en) | 2020-04-07 | 2021-10-07 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Selective modification of ion exchange membranes with iridium oxide by pH-controlled precipitation of IrOx species at the phase boundary |
Also Published As
| Publication number | Publication date |
|---|---|
| KR950032715A (en) | 1995-12-22 |
| CN1121964A (en) | 1996-05-08 |
| DE4418067C1 (en) | 1996-01-25 |
| CN1060823C (en) | 2001-01-17 |
| ES2120106T3 (en) | 1998-10-16 |
| RU2153538C2 (en) | 2000-07-27 |
| FI952484A (en) | 1995-11-25 |
| FI952484A0 (en) | 1995-05-22 |
| NO952035L (en) | 1995-11-27 |
| NO952035D0 (en) | 1995-05-23 |
| JPH0841668A (en) | 1996-02-13 |
| ATE170936T1 (en) | 1998-09-15 |
| DE59503494D1 (en) | 1998-10-15 |
| RU95108225A (en) | 1997-05-10 |
| EP0684324A1 (en) | 1995-11-29 |
| TW396212B (en) | 2000-07-01 |
| EP0684324B1 (en) | 1998-09-09 |
| NO309332B1 (en) | 2001-01-15 |
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