WO2009007440A2

WO2009007440A2 - Process for the electrochemical purification of aluminium

Info

Publication number: WO2009007440A2
Application number: PCT/EP2008/059053
Authority: WO
Inventors: Matthias Maase; Guenther Huber; Ingo Richter; Itamar Malkowsky; Andreas Fischer
Original assignee: Basf Se
Priority date: 2007-07-12
Filing date: 2008-07-11
Publication date: 2009-01-15
Also published as: WO2009007440A3

Abstract

The present invention relates to a process for the electrochemical purification of aluminium, which comprises the steps (a) provision of an electrolysis apparatus having at least one anode and at least one cathode in an electrolysis space, where the at least one anode and the at least one cathode are connected by an electrolyte and the electrolyte is present in the form of an electrolyte stream; (b) oxidation at the at least one anode which contains aluminium and at least one of the additional metals antimony, lead, iron, bismuth, tin, zinc or copper, where aluminium and the at least one additional metal go at least partly into the electrolyte in the form of their ions; (c) discharge of part of the electrolyte stream from the electrolysis space, where the substream contains at least part of the ions of aluminium and of the at least one additional metal ion; (d) removal of at least part of the at least one additional metal ion from the substream; (e) introduction of the substream which has been depleted in additional metal ions in step (d) into the electrolysis space and (f) deposition of the aluminium from the substream fed in in step (e) on the at least one cathode, where the electric current density at the at least one cathode is at least 50 A/m2.

Description

Process for the electrochemical purification of aluminum

description

The present invention relates to a process for the electrochemical purification of aluminum.

Aluminum is an important material that is used predominantly in the automotive and aircraft industries, as well as in mechanical engineering, construction and as packaging material.

Here, a large-scale purification of aluminum in its extraction and the purification of recycled aluminum (so-called secondary aluminum) is of importance.

Both in the production of aluminum and in its purification, the electrolysis plays a major role.

The conventional method for technical aluminum production is based on the so-called Hall Heroult process.

This alumina is dissolved in the form of Bauxid and cathodically deposited by means of direct current from a melt at temperatures of about 1000 ⁰ C.

US Pat. No. 6,881,321 also describes the electrolytic purification of aluminum.

Despite the methods known in the art, there is a need for alternative methods that can result in cleaner aluminum contents.

An object of the present invention is thus to provide such a method.

The object is achieved by a process for the electrochemical purification of aluminum containing the steps

(a) providing an electrolyzer having at least one anode and at least one cathode in an electrolysis space, wherein the at least one anode and the at least one cathode are connected by an electrolyte and the electrolyte is in the form of an electrolyte flow;

B07 / 0287PC IB / EBÜ / arw (b) oxidation at the at least one anode containing aluminum and at least one of the foreign metals antimony, lead, iron, bismuth, tin, zinc or copper, wherein aluminum and the at least one foreign metal at least partially pass into the electrolyte in the form of their ions;

(c) discharging a portion of the electrolyte flow from the electrolyzer compartment, the partial flow at least partially containing the ions of the aluminum and the at least one extraneous metal ion;

(d) depletion of the at least one foreign metal ion in the partial stream;

(e) supplying the partial stream depleted of foreign metal ion in step (d) to the electrolysis space and

(F) deposition of the aluminum from the supplied in step (e) partial flow at the at least one cathode, wherein at the at least one cathode, an electrical current density of at least 50 A / m ² is applied.

It has been found that in electrically meaningful methods electrical current densities of at least 50 A / m ^{2 are} required, which, however, have the consequence that at the anode in addition to aluminum, other metals in the electrolyte pass as ions and that in addition to these the cathode are deposited, so that the purity of the aluminum obtained is significantly reduced, which leads in extreme cases to the fact that the electrolysis has no cleaning effect.

It should be distinguished here that alloy constituents of the at least one anode as such may not be completely dissolved and removed as so-called "anode sludge". In addition, metals and other elements can first go into solution, but they precipitate for example in the form of chlorides (such as magnesium chloride) and can also be easily removed.

Therefore, the electrolysis room can have one or more identical or different filters. Accordingly, one or more of steps (a) through (f) may be followed by a filtration step.

It has now surprisingly been found that especially the foreign metals antimony, lead, iron, bismuth, tin, zinc or copper are particularly problematic and can reduce the purity of the aluminum by cathodic co-deposition.

B07 / 0287PC US Pat. No. 6,881,321 describes the electrolytic cleaning at such low electrical current densities, short test periods and with uncontaminated electrolyte that this problem does not occur, so that the desired cleaning effect already occurs through the electrolysis alone.

However, this is no longer possible if the electric current density is at least 50 A / m ² at the cathode, on which aluminum is to be deposited.

The electric current density is defined as the quotient of the current intensity and the effective electrode area during the electrolysis.

The electrical current density is preferably at least 100 A / m ² , more preferably at least 400 A / m ² and in particular at least 650 A / m ² .

In step (a) of the inventive method for the electrochemical purification of aluminum, an electrolysis device is provided which has at least one anode and at least one cathode in an electrolysis space, wherein the at least one anode and the at least one cathode are connected by an electrolyte and the electrolyte in Form of an electrolyte flow, or a stream is present.

Here, the at least one anode in addition to aluminum contains at least one of the foreign metals antimony, lead, iron, bismuth, tin, zinc or copper.

An anode can be used or several anodes can be used. These may have the same composition or have different compositions. The same applies to the cathode (s).

Preferably, the anode contains the primary or secondary aluminum to be cleaned in the form of alloys or aluminum scrap, which can be recycled.

These aluminum sources can have a different content of aluminum and foreign metals.

Types of such alloys or scrap are known in the art.

Thus, so-called "aluminum master alloys" are summarized according to the standards DIN EN 575, DIN EN 1780-1 and DIN EN 1780-2. Typical impurities in aluminum smelting are, for example, in Klaus Krone, Vereinigung Deutscher

B07 / 0287PC Schmelzhütten eV, aluminum publishing house marketing and communication GmbH, 2000, pages 237 ff. (ISBN 3-00-003839-6) described. In addition, special aluminum scrap are summarized in parts 2 to 16 of the standard DIN EN 13920. For example, Part 2 of the DIN standard deals with unalloyed aluminum scrap, while Part 3 refers to wire and cable scrap.

The at least one anode preferably has the composition of a scrap according to one of the parts 2 to 16 of the standard DIN EN 13920.

Preferably, the at least one anode contains AI with a weight fraction of at least 50 wt .-%, preferably 75 wt .-%, more preferably at least 90 wt .-% based on the total weight of the at least one anode.

The composition of the cathode can be selected in a known manner. In this case, for example, a pure aluminum cathode can be used. The deposition on graphite felts, metal fabrics, glass fiber fabrics and graphite fabrics is possible, so that directly composites can be obtained. Preferably, a three-dimensional cathode is used. Further examples of cathode materials are stainless steel, nickel-base alloys, graphite, copper and preferably aluminum.

The shape of the anode and the cathode can be chosen freely in principle. Preferably, arrangements known in the art are selected, wherein to achieve a high surface, an anode in porous form or in the form of a shaking electrode is preferably selected. The electrolyte is kept in motion by means known in the art to create an electrolyte flow, allowing the partial flow to drain in step (c). Accordingly, the at least one anode and the at least one cathode can be flowed through or flowed through.

Suitable arrangements are described in Chapter 4 of Keith Scott Electrochemical Process for Clean Technology, The Royal Society of Chemistry 1995 (ISBN 0-85404-506-6). In particular, cells with rotating electrodes (page 83, flow arrangements (page 85) and particulate electrodes (page 88)) are preferred.

In order to effectively prevent one or more of the foreign metals from being deposited on the cathode before they can be depleted in step (d) of the process of the invention, the electrolysis space preferably comprises release means separating the space into an anode and cathode space. In particular, it is preferred

B07 / 0287PC that these release agents prevent the direct transition of the foreign metal ions from anode to cathode or delay such that a depletion of the or the foreign metal ions in the partial flow is possible.

Suitable release agents here are frits, membranes, fabrics, perforated plates and flow webs.

These can be made of different materials. For example, separators in the form of glass frits, Teflon membrane, ceramic membranes, fiberglass fabrics or Teflon fabrics can be used. The flow webs can also ensure that in a corresponding arrangement a desired Beströ- tion or extraction is possible.

The inventive method for the electrochemical purification of aluminum is preferably carried out in such a way that the substream in step (c) is discharged from the anode space of the electrolyte stream and fed to the cathode space in step (e).

The electrolyte is typically a molten salt having a water content of less than 0.1% by weight, based on the total amount of the electrolyte.

Especially preferred are electrolytes containing an ionic liquid. In this case, it is particularly preferred if the anion of the ionic liquid is tetrachloroaluminate.

The cation used is preferably dialkylimidazolium cations in which the two alkyl groups, identical or different, branched or unbranched, may be substituted or unsubstituted by one or more phenyl groups and have 1 to 6 carbon atoms.

Preference is given to benzylmethylimidazolium, hexylmethylimidazolium, butylmethylimidazolium, ethylmethylimidazolium. Most preferably, the ionic liquid has a formula KaCl x AICI ₃ , wherein Ka one of the above-mentioned imidazolium cations and x has a value of 1, 4 to 1, 7, in particular 1, 5 comprises.

However, other ionic liquids can also be used. Such ionic liquids are described, for example, in DE-A 10 2005 017 733.

B07 / 0287PC Generally preferred are ionic liquids which have cations which are selected from the compounds of the formulas (IVa) to (IVw):

(IVd) (IVe) (IVf)

(ivg) (IVg ') (IVh)

(IVi) (ivj) (IVj ')

B07 / 0287PC

(IVm) (IVm ') (IVn)

(IVp) (IVq) (IVq ')

B07 / 0287PC

(IVq ") (IVr) (IVr ')

(IVr ") (IVs) (IVt)

(IVu) (IVv) (IVw)

and oligomers containing these structures.

Further suitable cations are compounds of the general formula (IVx) and (IVy)

R ^z R ^z

3 ^{l +} 1 ^{l +} 1

R-PR SR ¹

I R R

(IVx) (IVy)

and oligomers containing this structure.

In the above formulas (IVa) to (IVy)

B07 / 0287PC • the radical R is hydrogen, a carbon-containing organic, saturated or unsaturated, acyclic or cyclic, aliphatic, aromatic or araliphatic, unsubstituted or interrupted by 1 to 5 heteroatoms or functional groups radical having 1 to 20 carbon atoms; and

• the radicals R ¹ to R ⁹ independently of one another are hydrogen, a sulfo group or a carbon-containing organic, saturated or unsaturated, acyclic or cyclic, aliphatic, aromatic or araliphatic, unsubstituted or interrupted by 1 to 5 heteroatoms or functional groups Radical having 1 to 20 carbon atoms, wherein the radicals R ¹ to R ⁹ , which in the abovementioned formulas (IV) are bonded to a carbon atom (and not to a heteroatom), may additionally also stand for halogen or a functional group; or

two adjacent radicals from the series R ¹ to R ⁹ together also for a divalent, carbon-containing organic, saturated or unsaturated, acycli see or cyclic, aliphatic, aromatic or araliphatic, unsubstituted or interrupted by 1 to 5 heteroatoms or functional groups or substituted radical of 1 to 30 carbon atoms.

Suitable hetero atoms in the definition of the radicals R and R ¹ to R ^{9 are in} principle all heteroatoms in question which are capable of formally a -CH ₂ -, a -CH =, a -C≡ or a = C = group to replace. When the carbon-containing group contains heteroatoms, oxygen, nitrogen, sulfur, phosphorus and silicon are preferable. Particular preferred groups are -O-, -S-, -SO-, -SO ₂ -, -NR'-, -N =, -PR'-, -PR ' ₂ and -SiR' ₂ - called, where the radicals R 'are the remainder of the carbon-containing radical. The radicals R ¹ to R ⁹ are, in the cases in which those in the above formulas (IV) to a carbon atom (and not to a heteroatom) bound also be bound directly via the heteroatom.

Suitable functional groups are in principle all functional groups which may be bonded to a carbon atom or a heteroatom. Suitable examples are -OH (hydroxy), = 0 (especially as carbonyl group), -NH ₂ (amino), = NH (imino), -COOH (carboxy), -CONH ₂ (carboxamide), -SO ₃ H (sulfo ) and -CN (cyano). Fractional groups and heteroatoms can also be directly adjacent

B07 / 0287PC such that also combinations of several adjacent atoms, such as -O- (ether), -S- (thioether), -COO- (ester), -CONH- (secondary amide) or -CONR'- (tertiary amide) , are included, for example, di- (Ci-C ₄ alkyl) amino, dC ₄ - alkyloxycarbonyl or Ci-C ₄ alkyloxy.

Halogens are fluorine, chlorine, bromine and iodine.

The radical R preferably stands for

• unbranched or branched, unsubstituted or one to several times with

Hydroxyl, halogen, phenyl, cyano, C ₁ - to C ₆ -alkoxycarbonyl and / or sulfonic acid-substituted C ₁ - to C ₈ -alkyl having in total 1 to 20 carbon atoms, such as, for example, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl-1-propyl (isobutyl), 2-methyl-2-propyl (tert-butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1 -butyl, 3-methyl-1-butyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 2,2-dimethyl-propyl, 1-hexyl, 2-hexyl, 3-hexyl, 2 Methyl 1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2-methyl 3-pentyl, 3-methyl-3-pentyl, 2,2-dimethyl-1-butyl, 2,3-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl , 2,3-dimethyl-2-butyl, 3,3-dimethyl-2-butyl, 1-heptyl, 1-octyl, 1-nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tetradecyl, 1 -

Hexadecyl, 1-octadecyl, 2-hydroxyethyl, benzyl, 3-phenylpropyl, 2-cyanoethyl, 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- (n-butoxycarbonyl) -ethyl, trifluoromethyl, Difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonafluoroisobutyl, undecylfluoropentyl, undecylfluoroisopentyl, 6-hydroxyhexyl and propylsulfonic acid;

Glycols, butylene glycols and their oligomers having from 1 to 100 units and a hydrogen or a C 1 to C ₈ alkyl as end group, such as, for example, R ^A O- (CHR ^B -CH ₂ -O) _n -CHR ^B -CH ₂ - or R 1 - (CH ₂ CH ₂ CH ₂ CH ₂ O) _n -CH ₂ CH ₂ CH ₂ CH ₂ O- where R ^A and R ^{B are} preferably hydrogen, methyl or ethyl and n is preferably 0 to 3, in particular 3-oxabutyl , 3-oxapentyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl, 3,6,9-trioxadecyl, 3,6,9-trioxa-undecyl, 3,6,9,12-tetraoxatridecyl and 3,6,9 , 12-tetraoxatetradecyl;

• vinyl; and N, N-di-C ₁ to C ₆ -alkyl-amino, such as N, N-dimethylamino and N, N-

Diethylamino.

The radical R particularly preferably represents unbranched and unsubstituted C 1 - to C 18 -alkyl, such as, for example, methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl,

B07 / 0287PC 1-heptyl, 1-octyl, 1-decyl, 1-dodecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, especially for methyl, ethyl, 1-butyl and 1-octyl and for CH ₃ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ - and CH ₃ CH ₂ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ - where n is O to third

The radicals R ¹ to R ⁹ are preferably each independently

• hydrogen;

• halogen;

• a functional group; Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted and / or interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino Ci Ci- ₈ alkyl;

Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted and / or interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino C ₂ -Ci _8- alkenyl;

Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkoxy, halogen, heteroatoms and / or heterocycles substituted C ₆ -C ₂ -aryl;

• optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted _{_C5-Ci2} cycloalkyl;

• optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted _{_C5-Ci2} cycloalkenyl; or

Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy,

Halogen, heteroatoms and / or heterocycles substituted five- to six-membered, oxygen, nitrogen and / or sulfur atoms containing heterocycle means; or

two adjacent radicals together for

• an unsaturated, saturated or aromatic, optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles and optionally substituted by one or more oxygen,

B07 / 0287PC Substance and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups interrupted ring.

Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted d- to C-is-alkyl is preferably methyl, ethyl, 1-propyl, 2-propyl, 1-butyl , 2-butyl, 2-methyl-1-propyl (isobutyl), 2-methyl-2-propyl (tert-butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1 butyl, 3-methyl-1-butyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 2,2-dimethyl-1-propyl, 1-hexyl, 2-hexyl, 3-hexyl, 2- Methyl 1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2-methyl 3-pentyl, 3-methyl-3-pentyl, 2,2-dimethyl-1-butyl, 2,3-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, 2,3-dimethyl-2-butyl, 3,3-dimethyl-2-butyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, 1,1,3,3-tetramethylbutyl, 1- Nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tridecyl, 1-tetradecyl, 1-pentadecyl, 1-hexadecyl, 1-heptadecyl, 1-octadecyl, cyclopentylmethyl, 2-cyclopentylethyl, 3-cyclopentylpropyl, Cyc lohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, benzyl (phenylmethyl), diphenylmethyl (benzhydryl), triphenylmethyl, 1-phenylethyl, 2-phenylethyl, 3-phenylpropyl, a, a-dimethylbenzyl, p-tolylmethyl, 1 (p-butylphenyl) -ethyl, p-chlorobenzyl, 2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl, 2-cyanoethyl, 2-cyanopropyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 2-butoxycarbonylpropyl, 1, 2-di- (methoxycarbonyl) -ethyl, methoxy, ethoxy, formyl, 1,3-dioxolan-2-yl, 1,3-dioxan-2-yl, 2-methyl-1,3-dioxolan-2 yl, 4-methyl-1,3-dioxolan-2-yl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-aminoethyl, 2-aminopropyl, 3-aminopropyl, 4- Aminobutyl, 6-aminohexyl, 2-methylaminoethyl, 2-methylaminopropyl, 3-methylaminopropyl, 4-methylaminobutyl, 6-methylaminohexyl, 2-dimethylaminoethyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 4-dimethylaminobutyl, 6- Dimethylaminohexyl, 2-hydroxy-2,2-dimethylethyl, 2-phenoxyethyl, 2-phenoxypropyl, 3 Phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl, 2-methoxyethyl, 2-methoxypropyl, 3-methoxypropyl, 4-methoxybutyl, 6-methoxyhexyl, 2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxybutyl, 6-ethoxyhexyl , Acetyl, C _n F ₂ ( _n ) + (ib) H 2a + b with n equal to 1 to 30, 0 <a <n and b = 0 or 1 (for example CF ₃ , C ₂ F ₅ , CH ₂ CH ₂ - C _(n - ₂ ) F _{2 (n-2) +1} , C ₆ F ₁₃ , C ₈ F ₁₇ , C ₁₀ F ₂₁ , C ₁₂ F ₂₅ ), chloromethyl, 2-chloroethyl, trichloromethyl, 1, 1-dimethyl 2-chloroethyl, methoxymethyl, 2-butoxyethyl, diethoxymethyl, diethoxyethyl, 2-isopropoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, 2-methoxyisopropyl, 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- ( n-butoxycarbonyl) -ethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl, 5-hydroxy-3-oxa-pentyl, 8-hydroxy-3,6-dioxo-octyl, 1 1-hydroxy-3,6, 9-trioxa undecyl, 7-hydroxy-4-oxa-heptyl, 11-hydroxy-4,8-dioxa-undecyl, 15-hydroxy-4,8,12-trioxa-pentadecyl, 9-hydroxy-5-oxa nonyl, 14-hydroxy-5,10-dioxa-tetradecyl,

5-methoxy-3-oxa-pentyl, 8-methoxy-3,6-dioxo-octyl, 11-methoxy-3,6,9-trioxa-undecyl,

B07 / 0287PC 7-Methoxy-4-oxa-heptyl, 1-methoxy-4,8-dioxa-undecyl, 15-methoxy-4,8,12-trioxapentadecyl, 9-methoxy-5-oxa-nonyl, 14-methoxy 5,10-dioxa-tetradecyl, 5-ethoxy-3-oxa-pentyl, 8-ethoxy-3,6-dioxa-octyl, 1-ethoxy-3,6,9-trioxa-undecyl, 7-ethoxy 4-oxa-heptyl, 1-ethoxy-4,8-dioxa-undecyl, 15-ethoxy-4,8,12-trioxa-pentadecyl, 9-ethoxy-5-oxa-nonyl or 14-ethoxy-5,10 oxa-tetradecyl.

C ₂ optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles and / or interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups - to Ci ₈ alkenyl is preferably vinyl, 2-propenyl, 3-butenyl, cis-2-butenyl, trans-2-butenyl or C _n F ₂ (Na) - (ib) H2a-b with n < 30, 0 <a <n and b = 0 or 1.

In the case of C 1 -C ₁₂ -alkyl which is optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles, it is preferably phenyl, toIyI, xylene, α-naphthyl, β-naphthyl, Diphenylyl, chlorophenyl, dichlorophenyl, trichlorophenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, diethylphenyl, / so-propylphenyl, tert-butylphenyl, dodecylphenyl, methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl, 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-dimethoxyphenyl, 2,6-dichlorophenyl, 4-bromophenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 2, 6-Dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl, methoxyethylphenyl, ethoxymethylphenyl, methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl or C ₆ F _(S-3) H ₃ with 0 <a <5.

When optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles C ₅ - to C ₂ cycloalkyl is preferably cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl , Diethylcyclohexyl, butylcyclohexyl, methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl, C _n F ₂ (n- ₃ ) - (ib) H _{2 3} -b with n <30, 0 <a <n and b = 0 or 1 and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl.

When optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles C ₅ - to C ₂ cycloalkenyl is preferably 3-cyclopentenyl, 2-cyclohexenyl, 3-cyclohexenyl, 2.5 -Cyclohexadienyl or C _n F ₂ ( _n - ₃ ) -3 (ib) H 2 ₃ -3b with n <30, 0 <a <n and b = 0 or 1.

B07 / 0287PC An optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted five- to six-membered, oxygen, nitrogen and / or sulfur atoms containing heterocycle is preferably furyl, thiophenyl, pyrryl, Pyridyl, indolyl, benzoxazolyl, dioxolyl, dioxo, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl, dimethoxypyridyl or difluoropyridyl.

Two adjacent radicals together form an unsaturated, saturated or aromatic, optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles and optionally by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups interrupted ring, it is preferably 1, 3-propylene, 1, 4-butylene, 1, 5-pentylene, 2-oxa-1, 3-propylene, 1-oxa-1, 3-propylene, 2-oxa-1, 3-propylene, 1-oxa-1, 3-propenylene, 3-oxa-1, 5-pentylene, 1-aza-1, 3-propenylene, 1-CrC ₄ -alkyl 1-aza-1, 3-propenylene, 1, 4-buta-1, 3-dienylene, 1-aza-1, 4-buta-1, 3-dienylene or 2-aza-1, 4-buta-1 3-dienylene.

If the abovementioned radicals contain oxygen and / or sulfur atoms and / or substituted or unsubstituted imino groups, the number of oxygen and / or sulfur atoms and / or imino groups is not restricted. As a rule, it is not more than 5 in the radical, preferably not more than 4, and very particularly preferably not more than 3.

If the abovementioned radicals contain heteroatoms, then between two heteroatoms there are generally at least one carbon atom, preferably at least two carbon atoms.

Particularly preferably, the radicals R ¹ to R ⁹ are each independently

• hydrogen;

• straight-chain or branched, unsubstituted or monosubstituted to hydroxyl, halogen, phenyl, cyano, C ₁ to C ₆ alkoxycarbonyl and / or sulfonic acid-substituted C 1 - to C -alkyl having in total 1 to 20 carbon atoms, such as, for example, methyl , Ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl

1-propyl (isobutyl), 2-methyl-2-propyl (tert-butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2 Methyl 2-butyl, 3-methyl-2-butyl, 2,2-dimethyl-1-propyl, 1-hexyl, 2-hexyl, 3-hexyl, 2-methyl-1-pentyl, 3-methyl 1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-

B07 / 0287PC pentyl, 2-methyl-3-pentyl, 3-methyl-3-pentyl, 2,2-dimethyl-i-butyl, 2,3-dimethyl-1-butyl, 3,3-dimethyl-i-butyl, 2- Ethyl 1-butyl, 2,3-dimethyl-2-butyl, 3,3-dimethyl-2-butyl, 1-heptyl, 1-octyl, 1-nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, 2-hydroxyethyl, benzyl, 3-phenylpropyl, 2-cyanoethyl, 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- (n-

Butoxy-carbonyl) -ethyl, trifluoromethyl, difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonafluoroisobutyl, undecylfluoropentyl, undecylfluoroisopentyl, 6-hydroxyhexyl and propylsulfonic acid;

Glycols, butylene glycols and their oligomers having from 1 to 100 units and a hydrogen or a C 1 to C ₈ alkyl as end group, such as, for example, R ^A O- (CHR ^B -CH ₂ -O) _n -CHR ^B -CH ₂ - or R ^A O- (CH ₂ CH ₂ CH ₂ CH ₂ O) _n - CH ₂ CH ₂ CH ₂ CH ₂ O- with R ^A and R ^{B is} preferably hydrogen, methyl or ethyl and n is preferably 0 to 3, in particular 3- Oxabutyl, 3-oxapentyl, 3,6-dioxaheptyl,

3,6-dioxaoctyl, 3,6,9-trioxadecyl, 3,6,9-trioxaundecyl, 3,6,9,12-tetraoxatridecyl and 3,6,9,12-tetraoxatetradecyl;

• vinyl; and

N, N-di-C ₁ to C ₆ -alkyl-amino, such as N, N-dimethylamino and N, N-

Diethylamino.

Most preferably, the radicals R ¹ to R ⁹ independently of one another are hydrogen or C 1 - to C 1 -alkyl, such as, for example, methyl, ethyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl , for phenyl, for 2-hydroxyethyl, for 2-cyanoethyl, for 2- (methoxycarbonyl) ethyl, for 2- (ethoxycarbonyl) ethyl, for 2- (n-butoxycarbonyl) ethyl, for N, N-dimethylamino, for N, N-diethylamino, for chlorine and for CH ₃ O- (CH ₂ CH ₂ O) _n - CH ₂ CH ₂ - and CH ₃ CH ₂ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ - where n is the same 0 to 3.

Very particularly preferred pyridinium ions (IVa) are those in which

• one of the radicals R ¹ to R ^{5 is} methyl, ethyl or chlorine and the remaining radicals R ¹ to R ^{5 are} hydrogen;

• R ^{3 is} dimethylamino and the remaining radicals R ¹ , R ² , R ⁴ and R ^{5 are} hydrogen;

• all radicals R ¹ to R ^{5 are} hydrogen;

B07 / 0287PC • R ^{2 is} carboxy or carboxamide and the remaining radicals R ¹ , R ² , R ⁴ and R ⁵

Are hydrogen; or

• R ¹ and R ² or R ² and R ^{3 are} 1, 4-buta-1, 3-dienylene and the remaining R ¹ , R ² , R ⁴ and R ^{5 are} hydrogen;

and in particular those in which

• R ¹ to R ^{5 are} hydrogen; or

• one of the radicals R ¹ to R ^{5 is} methyl or ethyl and the remaining radicals R ¹ to R ^{5 are} hydrogen.

Very particularly preferred pyridinium ions (IVa) include 1-methylpyridinium, 1-ethylpyridinium, 1- (1-butyl) pyridinium, 1- (1-hexyl) pyridinium, 1- (1-octyl) -pyridinium, 1 (1-hexyl) -pyridinium, 1- (1-octyl) -pyridinium, 1- (1-dodecyl) -pyridinium,

1 - (1-tetradecyl) -pyridinium, 1- (1-hexadecyl) -pyridinium, 1, 2-dimethylpyridinium,

1-ethyl-2-methylpyridinium, 1- (1-butyl) -2-methylpyridinium, 1- (1-hexyl) -2-methylpyridinium, 1- (1-octyl) -2-methylpyridinium, 1- (1 Dodecyl) -2-methylpyridinium, 1- (1-tetradecyl) -2-methylpyridinium, 1- (1-hexadecyl) -2-methylpyridinium, 1-methyl-2-ethylpyridinium, 1, 2-diethylpyridinium, 1- (1-butyl) -2-ethylpyridinium, 1- (1-hexyl) -2-ethylpyridinium, 1- (1-octyl) -2-ethylpyridinium, 1- (1-dodecyl) -2-ethylpyridinium, 1 - (1 -trade ecy I) -

2-ethylpyridinium, 1- (1-hexadecyl) -2-ethylpyridinium, 1, 2-dimethyl-5-ethylpyridinium,

1, 5-diethyl-2-methyl-pyridinium, 1- (1-butyl) -2-methyl-3-ethyl-pyridinium, 1- (1-hexyl) -2-methyl-3-ethyl-pyridinium and 1 (1-Octyl) -2-methyl-3-ethylpyridinium, 1- (1-dodecyl) -2-methyl-3-ethylpyridinium, 1- (1-tetradecyl) -2-methyl-3-ethyl- pyridinium and 1- (1

Hexadecyl) -2-methyl-3-ethyl-pyridinium.

Very particularly preferred pyridazinium ions (IVb) are those in which

• R ¹ to R ^{4 are} hydrogen; or

• one of the radicals R ¹ to R ^{4 is} methyl or ethyl and the remaining radicals R ¹ to R ^{4 are} hydrogen.

Very particularly preferred pyrimidinium ions (IVc) are those in which

B07 / 0287PC • R ^{1 is} hydrogen, methyl or ethyl and R ² to R ^{4 are} independently hydrogen or methyl; or

• R ^{1 is} hydrogen, methyl or ethyl, R ² and R ^{4 are} methyl and R ^{3 is} hydrogen.

Very particularly preferred pyrazinium ions (IVd) are those in which

• R ^{1 is} hydrogen, methyl or ethyl and R ² to R ^{4 are} independently hydrogen or methyl; • R ^{1 is} hydrogen, methyl or ethyl, R ² and R ^{4 are} methyl and R ^{3 is} hydrogen;

• R ¹ to R ^{4 are} methyl; or

• R ¹ to R ^{4 are} methyl hydrogen.

Very particular preference is given to using as imidazolium ions (IVe) those in which

R ^{1 is} hydrogen, methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl, 1-octyl, 22 -H-hydroxydoxy-oxy-ethylthiophenyl, 22-CCyyaannooeeththyl and R ² to R ⁴ are each independently

Are hydrogen, methyl or ethyl.

Very particularly preferred imidazolium ions (IVe) which may be mentioned are 1-methylimidazolium, 1-ethylimidazolium, 1- (1-butyl) -imidazolium, 1- (1-octyl) -imidazolium, 1- (1-dodecyl) -imidazolium, 1- (1-Tetradecyl) -imidazolium, 1- (1-hexadecyl) -imidazolium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1- (1-butyl) -3-methylimidazolium, 1- (1 Butyl) -3-ethylimidazolium, 1- (1-hexyl) -3-methylimidazolium, 1- (1-hexyl) -3-ethylimidazolium, 1- (1-hexyl) -3-butylimidazolium, 1- (1-octyl) -3-methylimidazolium, 1- (1-octyl) -3-ethylimidazolium, 1- (1-octyl) -3-butylimidazolium, 1- (1-dodecyl) -3-methylimidazolium, 1- (1-dodecyl) -3-ethylimidazolium, 1- (1-dodecyl) -3-butylimidazolium, 1- (1-dodecyl) -3-octylimidazolium, 1- (1-tetradecyl) -3-methylimidazolium, 1 - (1-tetrad ecy I) -3-ethylimidazolium, 1- (1-tetradecyl) -3-butylimidazolium, 1- (1-tetradecyl) -3-octylimidazolium, 1- (1-hexadecyl) -3-methylimidazolium, 1- (1-hexadecyl) -3-ethylimidazolium, 1- (1-hexadecyl) -3-butylimidazolium, 1- (1-hexad ecyl) -3-octylimidazolium, 1, 2-dimethylimidazolium, 1, 2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1- (1-butyl) -2,3-dimethylimidazolium, 1 - ( 1-hexyl) -2,3-dimethylimidazolium, 1- (1-octyl) -2,3-dimethylimidazolium, 1,4-dimethylimidazolium, 1,3,4-trimethylimidazolium, 1,4-dimethyl 3-ethylimidazolium, 3-butylimidazolium, 1, 4-dimethyl-3-octylimidazolium, 1, 4,5-trimethylimidazolium, 1, 3,4,5-tetramethylimidazolium, 1, 4,5-trimethyl-3-ethylimidazolium , 1, 4,5-trimethyl-3-butylimidazolium and 1, 4,5-trimethyl-3-octylimidazolium.

B07 / 0287PC Very particular preference is given as Pyrazoliumionen (IVf), (IVg) or (IVg ') such, in which

• R ^{1 is} hydrogen, methyl or ethyl and R ² to R ^{4 are} independent of one another

Are hydrogen or methyl.

Very particularly preferred pyrazolium ions (IVh) are those in which

• R ¹ to R ^{4 are} independently hydrogen or methyl.

Very particular preference is given as 1-pyrazolinium (IVi) such as those in which

• independently of one another R ¹ to R ^{6 are} hydrogen or methyl.

Very particular preference is given to using 2-pyrazolinium ions (IVj) or (IVj ') as those in which

• R ^{1 is} hydrogen, methyl, ethyl or phenyl and R ² to R ^{6 are} independently hydrogen or methyl.

Very particular preference is given to using as 3-pyrazolinium (IVk) or (IVk ') such, in which

• R ¹ and R ^{2 are} independently hydrogen, methyl, ethyl or phenyl and R ³ to R ^{6 are} independently hydrogen or methyl.

Very particularly preferred imidazolinium ions (IVI) are those in which

• R ¹ and R ^{2 are} independently hydrogen, methyl, ethyl, 1-butyl or phenyl, R ³ and R ^{4 are} independently hydrogen, methyl or ethyl, and R ⁵ and R ^{6 are} independently hydrogen or methyl.

Very particular preference is given to imidazolinium ions (IVm) or (IVm ') those in which

B07 / 0287PC • R ¹ and R ^{2 are} independently hydrogen, methyl or ethyl and R ³ to R ^{6 are} independently hydrogen or methyl.

Very particular preference is given to using as imidazolinium ions (IVn) or (IVn ') those in which

• R ¹ to R ^{3 are} independently hydrogen, methyl or ethyl and R ⁴ to R ^{6 are} independently hydrogen or methyl.

Very particular preference is given to using thiazolium ions (IVo) or (I-Vo ') and oxazolium ions (IVp) as those in which

• R ^{1 is} hydrogen, methyl, ethyl or phenyl and R ² and R ^{3 are} independently hydrogen or methyl.

Very particular preference is given to using 1, 2,4-triazolium ions (IVq), (IVq ') or (IVq ") those in which

• R ¹ and R ^{2 are} independently hydrogen, methyl, ethyl or phenyl and R ^{3 is} hydrogen, methyl or phenyl.

Very particular preference is given to using as 1,3,3-triazolium ions (IVr), (IVr ') or (IVr ") those in which

• R ^{1 is} hydrogen, methyl or ethyl and R ² and R ^{3 are} independent of each other

W is hydrogen or methyl, or R ² and R ³ together are 1,4-buta-1,3-dienylene.

Very particularly preferred pyrrolidinium ions (IVs) are those in which

• R ^{1 is} hydrogen, methyl, ethyl or phenyl and R ² to R ^{9 are} independently hydrogen or methyl.

Very particular preference is given to using as imidazolidinium ions (IVt) those in which

B07 / 0287PC • R ¹ and R ^{4 are} independently hydrogen, methyl, ethyl or phenyl and R ² and R ³ and R ⁵ to R ^{8 are} independently hydrogen or methyl.

Very particular preference is given to using as ammonium ions (IVu) those in which

• R ¹ to R ^{3 are} independently C ¹ to C ¹ alkyl; or

• R ¹ and R ² together are 1, 5-pentylene or 3-oxa-1, 5-pentylene and R ^{3 is} d-C 18 alkyl, 2-hydroxyethyl or 2-cyanoethyl.

As very particularly preferred ammonium ions (IVu) may be mentioned methyl tri (1-butyl) -ammonium, N, N-dimethylpiperidinium and N, N-dimethylmorpholinium.

Examples of the tertiary amines from which the quaternary ammonium ions of the general formula (IVu) are derived by quaternization with the abovementioned radicals R are diethyl-n-butylamine, diethyl-tert-butylamine, diethyl-n-pentylamine, diethylhexylamine, Diethyloctylamine, diethyl (2-ethylhexyl) amine, di-n-propylbutylamine, di-n-propyl-n-pentylamine, di-n-propylhexylamine, di-n-propyloctylamine, di-n-propyl (2-ethyl - hexyl) amine, di-isopropylethylamine, di-iso-propyl-n-propylamine, di-isopropyl-butylamine, di-isopropylpentylamine, di-iso-propylhexylamine, di-isopropyloctylamine, di-iso-propyl (2-ethylhexyl ) -amine, di-n-butylethylamine, di-n-butyl-n-propylamine, di-n-butyl-n-pentylamine, di-n-butylhexylamine, di-n-butyloctylamine, di-n-butyl (2 ethylhexyl) amine, Nn-butylpyrrolidine, N-sec-butylpyrrodidine, N-tert-butylpyrrolidine, Nn-pentylpyrrolidine, N, N-dimethylcyclohexylamine, N, N-diethylcyclohexylamine, N, N-di-n-butylcyclohexylamine, N-n-propylpiperidine, N-isopropylpiperidine, Nn-butyl-pipe N-sec-butylpiperidine, N-tert-butylpiperidine, Nn-pentylpiperidine, Nn-butylmorpholine, N-sec-butylmorpholine, N-tert-butylmorpholine, Nn-pentylmorpholine, N-benzyl-N-ethylaniline, N-benzyl- Nn-propylaniline, N-benzyl-N-isopropylaniline, N-benzyl-Nn-butylaniline, N, N-dimethyl-p-toluidine, N, N-diethyl-p-toluidine, N, N-di- n-butyl-p-toluidine, diethylbenzylamine, di-n-propylbenzylamine, di-n-butylbenzylamine, diethylphenylamine, di-n-propylphenylamine and di-n-butylphenylamine.

Preferred tertiary amines (IVu) are di-iso-propylethylamine, diethyl-tert-butylamine, diisopropyl-propylamine, di-n-butyl-n-pentylamine, N, N-di-n-butylcyclohexylamine and tertiary amines pentyl isomers.

Particularly preferred tertiary amines are di-n-butyl-n-pentylamine and tertiary amines of pentyl isomers. Another preferred tertiary amine having three identical residues is triallylamine.

B07 / 0287PC Very particular preference is given to using as guanidinium ions (IVv) those in which

• R ¹ to R ^{5 are} methyl.

As a very particularly preferred guanidinium ion (IVv) may be mentioned N, N, N ', N', N ", N" - hexamethylguanidinium.

Very particular preference is given to using as cholinium ions (IVw) those in which

• R ¹ and R ^{2 are} independently methyl, ethyl, 1-butyl or 1-octyl and R ^{3 is} hydrogen, methyl, ethyl, acetyl, -SO ₂ OH or -PO (OH) ₂ ;

R ^{1 is} methyl, ethyl, 1-butyl or 1-octyl, R ^{2 is} a -CH ₂ -CH ₂ -OR ⁴ group and R ³ and R ⁴ independently of one another are hydrogen, methyl, ethyl, acetyl,

-SO ₂ OH or -PO (OH) ₂ ; or

• R ^{1 is} a -CH ₂ -CH ₂ -OR ⁴ group, R ^{2 is} a -CH ₂ -CH ₂ -OR ⁵ group and R ³ to R ^{5 are} independently hydrogen, methyl, ethyl, acetyl, -SO ₂ OH or -PO (OH) ₂ are.

Particularly preferred cholinium ions (IVw) are those in which R ^{3 is} selected from hydrogen, methyl, ethyl, acetyl, 5-methoxy-3-oxa-pentyl, 8-methoxy-3,6-dioxo-octyl, 1 1-methoxy 3,6,9-trioxa undecyl, 7-methoxy-4-oxa-heptyl, 11-methoxy-4,8-dioxa undecyl, 15-methoxy-4,8,12-trioxa-pentadecyl, 9-methoxy 5-oxa-nonyl, 14-methoxy-5,10-oxa-tetradecyl, 5-ethoxy-3-oxa-pentyl, 8-ethoxy-3,6-dioxa-octyl, 11-ethoxy-3,6,9 trioxa undecyl, 7-ethoxy-4-oxa-heptyl, 1-ethoxy-4,8-dioxa-undecyl, 15-ethoxy-4,8,12-trioxa-pentadecyl, 9-ethoxy-5-oxa nonyl or 14-ethoxy-5,10-oxa-tetradecyl.

Very particularly preferred as phosphonium ions (IVx) are those in which

R ¹ to R ^{3 are,} independently of one another, C 1 -C ₈ -alkyl, in particular butyl, isobutyl, 1-hexyl or 1-octyl.

Among the above-mentioned heterocyclic cations, the pyridinium ions, pyrazolinium, pyrazolium ions and imidazolinium and imidazolium ions are preferable. Furthermore, ammonium ions are preferred.

B07 / 0287PC Particular preference is given to 1-methylpyridinium, 1-ethylpyridinium, 1- (1-butyl) pyridinium, 1- (1-hexyl) pyridinium, 1- (1-octyl) pyridinium, 1- (1-hexyl) -pyridinium, 1- (1-Octyl) -pyridinium, 1- (1-dodecyl) -pyridinium, 1- (1-tetradecyl) -pyridinium, 1- (1-hexadecyl) -pyridinium, 1, 2-dimethylpyridinium, 1- Ethyl 2-methylpyridinium, 1- (1-butyl) -2-methylpyridinium, 1- (1-hexyl) -2-methylpyridinium, 1- (1-octyl) -2-methylpyridinium, 1- (1-dodecyl) - 2-methylpyridinium, 1- (1-tetradecyl) -2-methylpyridinium, 1- (1-hexadecyl) -2-methylpyridinium, 1-methyl-2-ethylpyridinium, 1, 2-diethylpyridinium, 1- (1-butyl) - 2-ethylpyridinium, 1- (1-hexyl) -2-ethylpyridinium, 1- (1-octyl) -2-ethylpyridinium, 1- (1-Dodecyl) -2-ethylpyridinium, 1- (1-tetradecyl) - 2-ethylpyridinium, 1- (1-hexadecyl) -2-ethyl-pyridinium, 1, 2-dimethyl-5-ethylpyridinium, 1, 5-diethyl-2-methylpyridinium, 1- (1-butyl) - 2-methyl-3-ethylpyridinium, 1- (1-hexyl) -2-methyl-3-ethylpyridinium, 1- (1-octyl) -2-methyl-3-ethyl-pyridinium, 1- (1 -Dod ecyl) -2-methyl-3-ethylpyridinium, 1- (1-tetra-decyl) -2-methyl-3-ethylpyridinium, 1- (1-hexadecyl) -2-methyl-3-ethylpyridinium .

1-methylimidazolium, 1-ethylimidazolium, 1- (1-butyl) -imidazolium, 1- (1-octyl) -imidazolium, 1- (1-dodecyl) -imidazolium, 1- (1-tetradecyl) -imidazolium, 1- (1-hexadecyl) imidazolium, 1, 3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1- (1-butyl) -3-methylimidazolium, 1- (1-hexyl) -3-methylimidazolium, 1 - (1-octyl) -3-methylimidazolium, 1- (1-dodecyl) -3-methylimidazolium, 1- (1-tetradecyl) -3-methylimidazolium, 1- (1-hexadecyl) -3-methylimidazolium, 1, 2-dimethylimidazolium, 1, 2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1- (1-butyl) -2,3-dimethylimidazolium, 1- (1-hexyl) -2, 3-dimethylimidazolium and 1- (1-octyl) -2,3-dimethylimidazolium, 1, 4-dimethylimidazolium, 1, 3,4-trimethylimidazolium, 1, 4-dimethyl-3-ethylimidazolium, 3-butyl tylimidazolium, 1, 4-dimethyl-3-octylimidazolium, 1, 4,5-trimethylimidazolium, 1, 3,4,5-tetramethylimidazolium, 1, 4,5-trimethyl-3-ethylimidazolium, 1, 4,5-trimethyl- 3-butylimidazolium and 1, 4,5-trimethyl-3-octylimidazolium.

The metal cations [M ¹ ] ⁺ , [M ² ] ⁺ , [M ³ ] ⁺ , [M ⁴ ] ²⁺ and [M ⁵ J ³⁺ mentioned in formulas (IIIa) to (NIj) are generally to metal cations of the 1st, 2nd, 6th, 7th, 8th, 9th, 10th, 1 1st, 12th and 13th group of the periodic table. Suitable metal cations are, for example, Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Cr ³⁺ , Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Ni ²⁺ , Cu ^{2 +} , Ag ⁺ , Zn ²⁺ and Al ³⁺ .

As anions, in principle, all anions can be used, provided that AICI ₄ ^" and / or Al ₂ Cl ₇ ^" are predominantly present.

The anion [Y] "^'of the ionic liquid is for example selected from

The group of halides and halogen-containing compounds of the formula:

B07 / 0287PC F, Cr, Br ^" , BF ₄ ^" , PF ₆ ^" , Al ₃ Cl ₁₀ ^" , AIBr ₄ ^" , FeCl ₄ ^" , BCI ₄ ^" , SbF ₆ ^" , AsF ₆ , -ZnCl ₃ ^" , SnCl ₃ ^" , CuCl ₂ ^" , CF ₃ SO ₃ ^" , (CF ₃ SOs) ₂ N-, CF ₃ CO ₂ ^" , CCI ₃ CO ₂ ^" , CN ^" , SCN ^" , OCN ^"

• the group of sulfates, sulfites and sulfonates of the general formula: SO ₄ ^{2 "} , HSO ₄ ^" , SO ₃ ^{2 "} , HSO ₃ ^" , ROSO ₃ ^" , R ³ SO ₃ ^" • the group of phosphates of the general formula PO ₄ ^{3 "} , HPO ₄ ^2" , H ₂ PO ₄ ^" , R ³ PO ₄ ^2" , HR ³ PO ₄ ^" , R ³ R ^b P0 ₄ ^"

The group of phosphonates and phosphinates of the general formula: R ³ H PO ₃ ^" , R ³ R ^b PO ₂ ^" , R ³ R ^b PO ₃ ^"

The group of phosphites of the general formula: PO ₃ ^{3 "} , HPO ₃ ^2" , H ₂ PO ₃ ^" , R ³ PO ₃ ^2" , R ³ HPO ₃ ^" , R ³ R ^b PO ₃ ^"

The group of phosphonites and phosphinites of the general formula: R ³ R ^b PO ₂ ^" , R ³ HPO ₂ ^" , R ³ R ^b P 0 ^" , R ³ HPO ^"

• the group of carboxylic acids of the general formula: R ³ COO ^" • the group of borates of the general formula:

BO ₃ ^{3 "} , HBO ₃ ^2" , H ₂ BO ₃ ^" , R ³ R ^b BO ₃ ^" , R ³ HBO ₃ ^" , R ³ BO ₃ ^2" , B (0R ³ ) (0R ^b ) (0R ^c ) (0R ^d ) ^" , B (HSO ₄ ) ^" , B (R ³ SO ₄ ) -

• the group of boronates of the general formula: R ³ BO ₂ ^{2 "} , R ³ R ^b B0 ^" • the group of carbonates and carbonic esters of the general formula: HCO ₃ ^" , CO ₃ ^2" , R ³ CO ₃ ^"

The group of silicates and silicic acid esters of the general formula: SiO ₄ ^{4 "} , HSiO ₄ ^3" , H ₂ SiO ₄ ^{2 "} , H ₃ SiO ₄ ^" , R ³ SiO ₄ ^{3 "} , R ³ R ^b Si0 ₄ ^2" , R ³ R ^b R ^c Si0 ₄ ^" , HR ³ SiO ₄ ^2" , H ₂ R ³ SiO ₄ ^" , HR ³ R ^b Si0 ₄ ^" • the group of alkyl or aryl silane salts of the general formula: R ³ SiO ₃ ^{3 "} , R ³ R ^b Si0 ₂ ^2" , R ³ R ^b R ^c Si0 ^" , R ³ R ^b R ^c Si0 ₃ ^" , R ³ R ^b R ^c Si0 ₂ ^" , R ³ R ^b Si0 ₃ ^2"

The group of the carboxylic imides, bis (sulfonyl) imides and sulfonyl imides of the general formula:

the group of methides of the general formula:

B07 / 0287PC SO ₂ -R ³

R ^b -O ₉ S ^' SO, -R ^C

• the group of alkoxides and aryloxides of the general formulas: RO ^" ; the group of the halometalates of the general formula [M _q Hal _r ] ^s" , where M is a metal and Hal is fluorine, chlorine, bromine or iodine, q and r are all positive numbers and indicate the stoichiometry of the complex and s is an integer positive number indicating the charge of the complex; • the group of sulfides, hydrogen sulfides, polysulfides, hydrogen polysulfides and thiolates of the general formulas: S ² -, HS ^" , [Sv] ² -, [HSv] -, [R ³ S] -, where v is a whole positive number of 2 is up to 10;

• the group of complex metal ions such as Fe (CN) ₆ ^{3 "} , Fe (CN) ₆ ^4" , MnO ₄ ^" , Fe (CO) ₄ ^" .

In this R ^a , R ^b , R ^c and R ^d are each independently hydrogen, C 1 -C ₃₀ -alkyl, optionally interrupted by one or more non-adjacent oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups C ₂ -C ₈ alkyl, C ₆ -C ₄ aryl, C ₅ -C ₂ cycloalkyl or a five- to six-membered, oxygen-, nitrogen- and / or sulfur-comprising heterocycle, where two of them together form an unsaturated, saturated or aromatic ring optionally interrupted by one or more oxygen and / or sulfur atoms and / or one or more unsubstituted or substituted imino groups, where the radicals mentioned are each additionally denoted by functional groups, aryl, alkyl, aryloxy, alkyloxy, Halogen, heteroatoms and / or heterocycles may be substituted.

Therein, optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles Ci-Ci ₈ alkyl, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl , Pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, 1, 1-dimethylpropyl, 1, 1-dimethylbutyl, 1, 1, 3 , 3-tetramethylbutyl, benzyl, 1-phenylethyl, α, α-dimethylbenzyl, benzhydryl, p-tolylmethyl, 1- (p-butylphenyl) -ethyl, p-chlorobenzyl, 2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl , 2-cyanoethyl, 2

B07 / 0287PC Cyanopropyl, 2-methoxycarbonethyl, 2-ethoxycarbonylethyl, 2-butoxycarbonylpropyl, 1, 2-di- (methoxycarbonyl) -ethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, diethoxymethyl, diethoxyethyl, 1, 3-dioxolane 2-yl, 1, 3-dioxan-2-yl, 2-methyl-1,3-dioxolan-2-yl, 4-methyl-1,3-dioxolan-2-yl, 2-isopropoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, chloromethyl, trichloromethyl, trifluoromethyl, 1,1-dimethyl-2-chloroethyl, 2-methoxyisopropyl, 2-ethoxyethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl, 2,2,2-trifluoroethyl, 2- Hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-aminoethyl, 2-aminopropyl, 4-aminobutyl, 6-aminohexyl, 2-methylaminoethyl, 2-methylaminopropyl, 3-methylaminopropyl, 4- Methylaminobutyl, 6-methylaminohexyl, 2-dimethylaminoethyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 4-dimethylaminobutyl, 6-dimethylaminohexyl, 2-hydroxy-2,2-dimethylethyl, 2-phenoxyethyl, 2-phenoxypropyl, 3 Phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl , 2-Methoxyethyl, 2-methoxypropyl, 3-methoxypropyl, 4-methoxybutyl, 6-methoxyhexyl, 2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxybutyl or 6-ethoxyhexyl.

Optionally C ₂ -C ₈ -alkyl which is interrupted by one or more non-adjacent oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups are, for example, 5-hydroxy-3-oxapentyl, 8-hydroxy-3, 6-dioxaoctyl, 1 1-hydroxy-3,6,9-trioxaundecyl, 7-hydroxy-4-oxaheptyl, 1-hydroxy-4,8-dioxaundecyl, 15-hydroxy-4,8,12-trioxapentadecyl, 9- Hydroxy-5-oxa-nonyl, 14-hydroxy-5,10-oxatetradecyl, 5-methoxy-3-oxapentyl, 8-methoxy-3,6-dioxo-octyl, 11-methoxy-3,6,9-trioxaundecyl, 7-Methoxy-4-oxaheptyl, 1-methoxy-4,8-dioxa- undecyl, 15-methoxy-4,8,12-trioxapentadecyl, 9-methoxy-5-oxanonyl, 14-methoxy-5,10-oxatetradecyl , 5-ethoxy-3-oxapentyl, 8-ethoxy-3,6-dioxaoctyl, 1-ethoxy-3,6,9-trioxaundecyl, 7-ethoxy-4-oxaheptyl, 1-ethoxy-4,8-dioxaundecyl , 15-ethoxy-4,8,12-trioxapentadecyl, 9-ethoxy-5-oxanonyl or 14-ethoxy-5,10-oxatetradecyl.

If two radicals form a ring, these radicals can be taken together, for example, as fused building block 1, 3-propylene, 1,4-butylene, 2-oxa-1,3-propylene, 1-oxa-1,3-propylene, 2-oxa 1, 3-propenylene, 1-aza-1, 3-propenylene, 1-C 1 -C ₄ -alkyl-1-aza-1, 3-propenylene, 1, 4-buta-1, 3-dienylene, 1 Aza-1, 4-buta-1, 3-dienylene or 2-aza-1, 4-buta-1, 3-dienylene mean.

The number of non-adjacent oxygen and / or sulfur atoms and / or imino groups is basically not limited, or is automatically limited by the size of the remainder or the ring building block. As a rule, it is not more than 5 in the respective radical, preferably not more than 4 or very particularly preferably not more than 3. Furthermore, at least one, preferably at least two, carbon atoms (e) are generally present between two heteroatoms.

B07 / 0287PC Substituted and unsubstituted imino groups may be, for example, imino, methylimino, iso-propylimino, n-butylimino or tert-butylimino.

The term "functional groups" are, for example, to the following: carboxy, carboxamide, hydroxy, di (Ci-C ₄ alkyl) amino, -C ₄ alkyloxycarbonyl, cyano or C ₄ alkoxy Here, Ci to C. _4- alkyl methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl or partially .Butyl.

Optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles C6-C ₄ aryl are for example phenyl, tolyl, xylyl, α-naphthyl, ß-naphthyl, 4-diphenylyl, chlorophenyl, dichlorophenyl , Trichlorophenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, diethylphenyl, isopropylphenyl, tert-butylphenyl, dodecylphenyl, methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl, 2, 6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-dimethoxyphenyl, 2,6-dichlorophenyl, 4-bromophenyl, 2- or 4-nitrophenyl, 2,4- or 2,6-dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl, methoxyethylphenyl or ethoxymethylphenyl.

Optionally substituted by functional groups, aryl, alkyl, aryloxy, halogen, heteroatoms and / or heterocycles substituted _{_C5-Ci2} cycloalkyl, for example cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl, Methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl.

A five- to six-membered, oxygen, nitrogen and / or sulfur-containing heterocycle is, for example, furyl, thiophenyl, pyryl, pyridyl, indolyl, benzoxazolyl, dioxolyl, dioxyl, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl, dimethylpyryl , Methoxifuryl, dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl.

Preferred anions are selected from the group of halides and halogen-containing compounds, the group of carboxylic acids, the group of sulfates, sulfites and sulfonates and the group of phosphates.

B07 / 0287PC Preferred anions are chloride, bromide, iodide, SCN ^", ^OCN", CN ^", acetate, Ci-C sulfate ₄ alkyl, R ^a ^-COO", R ³ SO ₃ ^", R ^a R ^b PO _^4", methanesulfonate, Tosylate, Ci-C ₄ Dialkylphospha- te, hydrogen sulfate or tetrachloroaluminate.

In step (b) of the process according to the invention for the electrochemical purification of aluminum, the anodization takes place on at least one anode containing aluminum and at least one of the foreign metals antimony, lead, iron, bismuth, tin, zinc or copper, wherein aluminum and the at least one Foreign metal at least partially pass into the electrolyte in the form of their ions.

In order to achieve a depletion of the foreign metal ions, a part of the electrolyte flow must be discharged from the electrolysis chamber. This is done in step (c), wherein the substream at least partially contains the ions of the aluminum and the at least one foreign metal ion. This can be ensured, in particular, by arranging the separating means described above in such a way that an anode and cathode space is created. In this case, the term anode space is understood to mean the space of the electrolysis space which is delimited by the anode and the separating means. Accordingly, the cathode space is the part of the electrolysis space which is delimited by the separating means and the at least one cathode. The release agent thus serve to avoid the direct transfer of the electrolyte from the anode compartment to the cathode compartment.

Outside of the electrolysis space then takes place in step (d) of the inventive method for the electrochemical purification of aluminum, the depletion of the foreign metal ions in the partial flow instead. In this case, the depletion takes place in step (d), more preferably by at least one of the following steps:

(d1) precipitation of the at least one foreign metal ion;

(d2) complexing of the at least one foreign metal ion; (d3) cementation of the at least one foreign metal ion;

(d4) Electrolytic deposition of the at least one foreign metal ion on a cathode, which is part of another electrolysis space, which is operated potentiostatically.

In step (d1), the at least one foreign metal ion is precipitated. In this case, one or more foreign metal ions can be precipitated. Preferably, the precipitation takes place in the form of a sulfide precipitation. In this case, aluminum can be kept in solution, so that then a cathodic deposition of the aluminum from the electrolyte to a purer aluminum cathode is possible.

B07 / 0287PC In step (d2), a complexing of the at least one foreign metal ion can take place. This has the consequence that either the complex can be removed more easily from the electrolyte, for example by precipitation, or that the complexation prevents deposition at the cathode in that the metal ion has a different potential as a result of the complex formation.

Suitable complexing agents are those containing nitrile groups or nitrogen-containing non-protic heterocycles such as pyridine, imidazole, methylimidazole, triazole.

In step (d3), cementation of the at least one foreign metal ion may be performed. The term cementation is understood to mean the deposition of the foreign metal ion on aluminum in the form of a local element. This can be made possible by adding aluminum particles to the partial stream.

However, other structures such as aluminum electrodes which are de-energized may be used. However, particles are preferred since they have a high surface area. At these particles, the deposition of the foreign metal takes place, at the same time aluminum goes into solution, so that also the deposition of aluminum in higher purity is possible.

The shape of the particles should be chosen so that the highest possible surface area is available. The aluminum particles are preferably flakes, needles, hollow bodies or other shapes. In this case, in particular aluminum chips can be used, which can be incurred, for example, as milling chips or as turning and drilling chips. Such chips are described for example in Krone, Association German smelters e.V., Aluminum-Verlag Marketing and Communication GmbH, pages 72 to 75.

Cementation as such is known and described, for example, in Keith Scott, Elctrochemical Processes for Clean Technology, The Royal Society of Chemistry (1995), Chapter 6.6, pages 164-165.

Both in cementaton and when using Al-containing anode and cathode activation is advantageous to free the AI surface of oxide layers. In principle, such methods are known in the art. This can be done for example by mechanical means as with a ball mill. In addition, a reductive activation can take place, with the aluminum oxide being converted into aluminum. Suitable reducing agents are hydrogen or diisobutylaluminum

B07 / 0287PC hydride (DIBAL). An etching process, for example, with iodine, hydrogen chloride gas, hydrochloric acid solutions, peroxides or Alkalimetallalkylate- or alcoholates is possible.

Particularly preferred in the context of cementation is the activation by etching with dilute aqueous HCl or trimethylsilanyl chloride and subsequent washing with toluene.

Finally, in step (d4), an electrolytic deposition of the at least one foreign metal ion on a cathode, which is part of another electrolysis space, such as a cell, which is operated potentiostatically, can take place.

Here, for example, the partial flow is passed into a further electrolytic cell, but at the cathode of this cell, however, the foreign metal ion, in particular copper, is selectively deposited. This can also be done depletion of Fremdmetalli- ons. The actual cathodic deposition of the aluminum then takes place after supply to the electrolysis room.

For the deposition of several metals or the multiple deposition of individual metals, a so-called voltage cascade can take place at several such cathodes. In this case, the deposition of the foreign metals is made possible by specific application of certain voltages. The selective deposition is described, for example, in Keith Scott, Electrochemical Processes for Clean Technology, The Royal Society of Chemistry 1995, Chapter 6.5.2 (page 147 ff.) And Chapter 6.5.5 (page 157 ff.).

Selective copper deposition is moreover particularly of B.J. Tierney et al., J. Electrochem. Soc, 145 (1998), 3110-3116 and F. Endres et al., Phys. Chem. Chem. Phys. 2000, 5455-5462.

The present invention will be explained in more detail with reference to the following examples.

Examples

Example 1 Al electrolysis at a technically relevant current density (comparative example) A magnetically stirred electrolytic cell rendered inert with dry nitrogen with electrodes arranged plane-parallel and having a size of 2 × 5 cm (10 cm ² ) at a distance of 9 mm at 95 ° C. in 80 ml of an electrolyte consisting of 1 - butyl-3-methyl-imidazolium chloride ^* 1, 5 AICI _{3 applied} a current of 0.6 A for 5 hours (current density 600 A / m ² ). The observed clamp voltage is 2V in the first 45 min and then varies in a range of 1, 2-1, 0V for the remaining 255

B07 / 0287PC minute The anode consists of compressed scrap parts made of aluminum beverage cans and has a composition of (AI 97.05%, Cu 0.18%, Fe 0.46%, Mg 1, 23%, Mn 0.87%, Si 0) in the elemental analysis , 17%, Ti 0.02%, Zn 0.02%). The cathode used is primary aluminum with an Al content of 99.9%. The electrodes are rinsed with acetone before use and dried. A targeted removal of the oxide layer is not performed. In the course of the experiment cathodic dendritic aluminum grows. This is mechanically separated from the cathode after the end of the electrolysis and washed with acetonitrile to remove adhering electrolyte. The elemental analysis shows a content of dendrites to Al 98.35%; Cu 0.16%; Fe 0.36%; Mg 0.30%; Mn 0.65%; Si 0.09%; Ti 0.02%; Zn 0.02%.

The very low cleaning effect makes it clear that at technically relevant current densities sufficient cleaning by exclusive electrolysis is not possible.

EXAMPLE 2 Multiple Use of the Electrolyte (Comparative Example) 385 g of an electrolyte consisting of 385 g of an electrolyte consisting of two 10 × 10 cm (100 cm ² ) electrodes 10 × 10 cm (100 cm ² ) arranged in a plane-parallel arrangement with dry nitrogen 1-ethyl-3-methyl-imidazolium chloride ^* 1, 5AICl3 at 95 ° C circulated by a pump. The anode consists of the alloy AIZnMgCuI, 5 (AW-7075, 3.4365, composition see below) and the cathode consists of 99.9% AI. At a current of 6 A and a voltage of 2.0-1.0 V, aluminum is anodically dissolved and cathodically deposited over a period of 10 hours. After the end of the electrolysis, the cathode is removed from the electrolyte and the dendritic coating mechanically removed, collected, washed with acetonitrile and its composition examined by elemental analysis.

The dry cathode is reused and, with continued use of the electrolyte, two more electrolysis runs are carried out. The voltage curve in the later electrolysis runs shows a much faster drop to values around 1, 0 V, which can be attributed to the after the first Elektrolyselauf oxide layer-free anode.

The elemental analysis yields the following contents:

Anode (AIZnMgCuI, 5): 90.00% AI; 0.7% Cu; 2.5% Mg; 6.5% Zn; 0.2% Fe

Cathode deposition first run: 98.87% AI; 0.07% Cu; 0.02% Mg; 0.72% Zn; 0.02%

Fe

Cathode deposition second run: 95.92% AI; 0.12% Cu; 0.06% Mg; 1, 02% Zn; 0.06% Fe

B07 / 0287PC Cathode deposition third run: 91, 59% AI; 0.44% Cu; 0.02% Mg; 2.21% Zn; 0.05% Fe

With increasing maturity, the foreign metal content increases significantly and the purity of the aluminum significantly. A refining is not feasible without additional cleaning procedures.

Example 3 Cementation

In a stirred, dry-nitrogen jacketed glass jacketed vessel, three independent electrolysis cells are individually connected to independent rectifiers. The individual electrolysis cells are constructed from two electrodes arranged in parallel with a size of 2 × 5 cm (10 cm ² ) at a distance of 9 mm. The 950 ml of an electrolyte consisting of 1-ethyl-3-methylimidazolium chloride ^* 1, 5AICI ₃ are kept at 95 ° C. during the electrolysis. In the first phase of the experiment, the first of the three cells (anode and cathode composed of 99.9% Al) at an electric current of 0.6 A and a voltage of 2.0-0.7 V anodically dissolves aluminum and cathodic deposited. In the second phase of the experiment, the first cell is disconnected from the rectifier but left in the electrolyte and cells two and three are operated (anode: AICuPbMg, AW-2030, 3.1645, cathode: 99.9% AI). In this case, a current of 0.6 A is applied to cell two and a current of 0.3 A at cell three. The voltage is at cell two at 2.0-0.8 V and at cell three at 1.5. 0.8 V. During the second phase of the experiment, an occupancy of the electroless cathode and anode of the first electrolysis cell with a black flaky layer is observed. After the experiment, the three pairs of electrodes are removed from the assembly, the dendritic cathode coating is mechanically removed with acetonitrile and both the composition of the dendritic cathode coating and the washing solution are investigated after distilling off the solvent.

The elementary analyzes yield the following contents:

Composition of the anodes used by cells two and three: Al 94%, Cu 3.7%, Mg 0.9%, Pb 0.8%, Fe 0.6%.

Solid content of the washing solution of the cathode of the first cell: Al 98.06%; Cu 0.90%; Pb 0.60%; Fe 0.37%.

Composition of the deposition on the cathode of cell two: AI 98.73%; Cu 0.85%; Pb 0.32%; Fe 0.11%.

B07 / 0287PC Composition of the deposition on the cathode of cell three: Al 99.07%; Cu 0.63%; Pb 0.21%; Fe 0.09%.

Significant proportions of the alloying metals of the anodes of spatially separated cells two and three are found in the wash solution of the first cell. Thus, the cementation of the alloying metals is observed in this system and can be used as a purification method of the electrolyte of dissolved portions of the alloying metals. Especially clear is the cleaning effect for lead.

Example 4 Potentiostatic Cu Deposition from the Contaminated Electrolyte Parallel to Al Refinig

In a stirred, dry-nitrogen jacketed glass jacketed vessel, three independent electrolysis cells are individually connected to independent rectifiers. The individual electrolysis cells are constructed from two electrodes arranged in parallel with a size of 2 × 5 cm (10 cm ² ) at a distance of 9 mm. The 950 ml of an electrolyte consisting of 1-ethyl-3-methyl-imidazolium chloride ^* 1, 5AICI ₃ are heated to 95 ° C before starting electrolysis. At the first of the three cells (anode of 99.9% Al, cathode of 99.9% Cu, reference electrode: 99.9% Cu) a potential of -0.4 V (vs. Cu) is applied for 10 hours. A current of 3.0 mA rising to 7.2 mA is observed at which the deposition of copper is realized. On cells two and three with alloy anodes (AICuPbMg, AW-2030, 3.1645) and cathodes of 99.9% AI, a current of 0.6 A is applied for 10 hours and a terminal voltage of 2.0-0.8V observed.

After the experiment, the three electrode pairs are removed from the structure, the cathode covering is mechanically removed with acetonitrile and the composition of the cathode coating is examined.

The elemental analysis gave the following contents:

Cathode Covering Cell 1: Al 33.29%, Cu 49.51%, Pb 12.85%, Fe 4.35%. Cathode coating cell 2: AI 98.41%; Cu 0.52%; Pb 0.55%; Fe 0.12%. Cathode Covering Cell 3: AI 98.63%; Cu 0.51%; Pb 0.47%; Fe 0.09%.

Thus, in this setup, the targeted and voltage controlled deposition of unwanted alloy metals of the anodes of cells two and three is shown at the cathode of cell one. If a used electrolyte in which alloying metals have been dissolved, eg Cu ⁽¹⁾ Cl, Pb ⁰⁰ Cl ₂ etc., is introduced into an electrolysis cell which has and becomes a reference electrode in the vicinity of the cathode

B07 / 0287PC When a suitable cell voltage of 0.4 V is applied to a copper reference electrode, alloy metals can be deposited on the cathode from the electrolyte. This can be done in terms of the foreign metal pure form but in deviations from the ideal value as an alloy.

EXAMPLE 5 Cementation-assisted Refining in a Flow Cell In an electrolytic cell inertized with dry nitrogen, composed of two 10 × 10 cm (100 cm ² ) electrodes 10 × 10 cm (10 cm) apart at a distance of 10 mm, 1013 g of an electrolyte consisting of 1 Ethyl 3-methyl-imidazolium chloride ^* 1, 5AICI ₃ at 95 ° C circulated by a pump. The electrolyte circuit runs through a heat exchanger from the pump, a glass tube filled with aluminum granules (5-12 mm, 78 mL) as cementation reactor, a glass frit and the electrolysis cell. The anode consists of the alloy AICuMgPb (AW-2030, 3.1645, composition see below) and the cathode consists of 99.9% Al. At a current of 6 A and a voltage of 2.0-1.0 V, aluminum is anodically dissolved and cathodically deposited over a period of 5.5 hours. After the end of the electrolysis, the cathode is removed from the electrolyte and the dendritic coating is mechanically removed, collected, washed with acetonitrile and water, and its composition is examined by elemental analysis. The black, loosely adhering coating on the aluminum granules in the cementation reactor is also mechanically removed, washed with acetonitrile and analyzed by elemental analysis.

The dry cathode is reused and, with further use of the electrolyte, 15 more electrolysis runs are carried out for between 5 and 10 hours, with losses of electrolyte by isolating the electrolysis product by adding fresh 1-ethyl-3-methyl-imidazolium chloride ^* 1, 5AICl3 be compensated. The voltage curve in the subsequent electrolysis runs shows a much faster drop to values around 1, 0 V.

The elemental analysis yields the following contents:

Composition of the anode used:

Al 94%, Cu 3.7%, Mg 0.9%, Pb 0.8%, Fe 0.6%.

Cathodic deposition after 15.5 h:

AI 98%, Cu 0.25%, C 0.1%, Cl 0.09%, Mg <0.01%. *

Cathodic deposition after 23 h:

Al 98%, Cu 0.18%, C 0.13%, Cl 0.18%, Pb 0.06%, Mg <0.01%. ^# Cathodic deposition after 32.5 h:

B07 / 0287PC Al 91%, Cu 0.16%, C <0.5%, Cl 1, 0%, Pb 0.06%, Mg <0.01%. ^# Cathodic deposition after 44.5 h:

Al 93%, Cu 0.04%, C 0.5%, Cl 0.02%, Pb <0.03%, Mg <0.01%. * Cathodic deposition after 49.5 h: Al 93%, Cu 0 , 03%, C <0.5% C, Cl 0.09%, Pb 0.01%, Mg <0.01%. * Cathode deposition after 55.5 h:

Al 96%, Cu 0.06%, C <0.5%, Cl 0.18%, Pb 0.02%, Mg <0.01%. * Cathode deposition after 60.5 h:

Al 95%, Cu 0.08%, C <0.5%, Cl 0.7%, Pb 0.03%, Mg <0.01%. * Cathode deposition after 70 h:

Al 95%, Cu 0.08%, C 0.5%, Cl 0.5%, Pb 0.03%, Mg <0.01%. *

Cathodic deposition after 76 h:

Al 97%, Cu 0.02%, C 0.7%, Cl 0.6%, Pb <0.01%, Mg <0.01%. *

*: the 100% missing part is oxygen, which is due to the formation of alumina by the aqueous workup of the cathode coating. The correct determination of oxygen in addition to aluminum is not possible due to the oxophilia of aluminum. For comparison, the composition of the cathode deposition is given after 44.5 h with water-free workup: cathode deposition after 44.5 h (with completely water-free work-up): Al 100%, Cu 0.03%, C <0.5% , Cl 0.14%, Pb 0.01%, Mg <0.01%.

Cementation product after 15.5 h: Cu 4.0%, Pb 1.7%.

The foreign metal content in the cathodically deposited aluminum can be significantly reduced by using the cementation reactor in the electrolyte circuit. The removal of the alloying metals in the cementation reactor leads to a refining of the aluminum used.

B07 / 0287PC

Claims

claims

1. A method for the electrochemical purification of aluminum comprising the steps

(b) oxidation at the at least one anode containing aluminum and at least one of the foreign metals antimony, lead, iron, bismuth, tin, zinc or copper, wherein aluminum and the at least one foreign metal at least partially pass into the electrolyte in the form of their ions;

(d) depletion of the at least one foreign metal ion in the partial stream;

2. The method according to claim 1, characterized in that the depletion in step (d) is carried out by at least one of the following steps:

(d1) precipitation of the at least one foreign metal ion; (d2) complexing of the at least one foreign metal ion; (d3) cementation of the at least one foreign metal ion; (d4) Electrolytic deposition of the at least one foreign metal ion on a cathode which is part of a further electrolysis space which is operated potentiostatically.

3. The method according to claim 2, characterized in that the precipitation takes place in step (d1) in the form of a sulfide precipitation.

B07 / 0287PC

4. The method according to claim 2, characterized in that the complexing in step (d2) by a nitrile groups or nitrogen-containing non-protic heterocycles containing complexing agents takes place.

5. The method according to claim 2, characterized in that the cementation in step (d3) takes place by adding aluminum particles to the partial flow.

6. The method according to claim 2, characterized in that the deposition in step (d4) takes place in a voltage cascade at a plurality of cathodes.

7. The method according to any one of claims 1 to 6, characterized in that the at least one anode has the composition of a scrap according to one of the parts 2 to 16 of the standard DIN EN 13920.

8. The method according to any one of claims 1 to 7, characterized in that the at least one anode is in the form of a shaking electrode.

9. The method according to any one of claims 1 to 8, characterized in that the electrolysis space has separating means which separates the space into an anode and cathode space.

10. The method according to claim 9, characterized in that the release agents are selected from the group consisting of frits, membranes, fabric, perforated plates and flow webs.

1 1. The method of claim 9 or 10, characterized in that the partial stream in step (c) discharged from the anode compartment of the electrolyte flow and in step (e) is fed to the cathode compartment.

12. The method according to any one of claims 1 to 1 1, characterized in that the electrolyte contains an ionic liquid.

13. The method according to claim 12, characterized in that the ionic liquid contains as the anion tetrachloroaluminate and / or heptachlorodialuminate.

B07 / 0287PC