DE102006016688B3 - Electrical deionization method for processing of rinsing waters from chemical and/or electro-chemical surface treatment of metals, comprises cleaning of metal-containing liquids by ion-exchanger along with recovery of ion-exchange material - Google Patents

Abstract

The electrical deionization method for processing of rinsing waters from chemical and/or electro-chemical surface treatment of metals, comprises cleaning of metal-containing liquids by ion-exchanger along with periodic recovery of ion-exchange material by electrodialysis. The processing takes place in a chamber consisting six partial chambers, which are separated by four separators (8) that are built as a diaphragm and/or ion-exchange membrane. The rinsing waters exhibit a portion of heavy metals in anionic and/or cationic form as well as with other components of process baths. The electrical deionization method for processing of rinsing waters from chemical and/or electro-chemical surface treatment of metals, comprises cleaning of metal-containing liquids by ion-exchanger along with periodic recovery of ion-exchange material by electrodialysis. The processing takes place in a chamber consisting six partial chambers, which are separated by four separators (8) that are built as a diaphragm and/or ion-exchange membrane. The rinsing waters exhibit a portion of heavy metals in anionic and/or cationic form as well as with other components of process baths. The partial chambers house an anode (9) or cathode (10) as a differently polarized electrode and one of the partial chambers housing an electrode contains an ion-exchange material that is directly contacted with the electrode. The individual chamber systems are combined into a complex unit for the operation of the method. The partial chambers filled with the ion-exchange material accommodate cationic and/or anionic ion-exchange material. The partial chambers are electrically connected in an electrically parallel or instrumentally sequential manner or by a bipolar electrode and/or a bipolar membrane. A separation device or an electrodialysis mechanism is connected to the electrical deionization module directly to a concentration chamber or to a concentration chamber for simultaneous or periodic metal separations and/or concentrations as well as pH value corrections. Ion-exchange and/or recovery for individual liquid currents, volume flow rate of a liquid current, flow intensity or chamber tension, temperature or unification of partial cycles are changed with respect to time. The electrodes are assigned to two of the partial chambers, which accommodate different ion-exchange material and lie next to each other and are separated by a bipolar membrane or a bipolar electrode. The ion-exchange materials are directly contacted with both the poles of the bipolar membrane or the bipolar electrode. Species of H +>or OH ->ions are electro-chemically produced for recovery of the ion-exchange material. Two partial chambers are present between the ion-exchanger chamber and the electrode chamber and are separated from them by two separators as well as undertake an electrodialytic concentration function and protection function against unwanted electrode reactions. In the current-free loading of the ion-exchange material, a rinsing water liquid current is led parallelly through both the chambers of the ion-exchange material, and simultaneously a recovery is carried out. Two independent liquid currents are led in separate cycles through the ion-exchanger chambers and undertake concentration functions by separators at the partial chambers adjacent to the ion-exchanger chambers. During the recovery of the ion-exchanger two separate liquid currents are flown through and a liquid current is parallelly flown through the anode chamber (1) and the cathode chamber (2).

Description

The The invention relates to an electrodeionization process for processing in the case of chemical and / or electrochemical surface treatment Rinsing waters produced by metals a proportion of heavy metals in anion and / or cation form as well as with other components of process baths, a purification of metal-containing liquids by ion exchange and periodic regeneration of the ion exchange material by electrodialysis with applied voltage or current flow having. Liquid systems enriched with cations or anions of heavy metals, z. B. rinse waters arise in the surface treatment of metals, in particular in electroplating and printed circuit board technology and in ablative processes such as pickling, etching, firing and the like, as well in the processing of metal-containing residues from chemistry, Metallurgy and environmental engineering.

Usually be for the treatment of rinse water rich in heavy metals chemical redox reactions, Precipitation processes, the chemical and electrochemical coagulation or flotation as well conventional ion exchange, electrodialysis and others used electrochemical processes. The procedures have z.T. the disadvantages of the whole Loss of heavy metals and others in the system Components, the use and entry of expensive chemicals Reduction and precipitation as well as flocculation and flotation. Another disadvantage is the formation of large quantities at heavy metal sludges, their storage or re-use partially prohibited, problematic or is expensive. In the case of electrochemical processes sometimes come even higher Energy expenditures. Although it forms during electrodialysis usually no mud, but it is not possible by electrodialysis the heavy metals from the sinks Completely and selectively remove. Electrolysis processes work in the Usually only effective for larger concentrations Comparison with electrodialysis. The conventional ion exchange technology Although allows a selective removal of heavy metals in a concentration range to a few ppm, but has as disadvantages high ion exchange costs, manual expenses as well as the need for subsequent ones chemical treatment and disposal of the eluate.

For some years, a technique has been available for the production of ultrapure water, which works according to the so-called electrodeionization. The spaces between separators of an electrodialysis cell or electrode chambers are filled with ion exchange material which absorbs dissolved components as a result of ion exchange reactions in the water. These are transported in the ion exchange material according to the electrical potential gradients and the properties of the limiting ion exchange membranes in the adjacent chambers. The ion exchange material is continuously regenerated by the electrochemically formed species of H ⁺ and OH ^- ions, respectively.

A successful transmission the principle of continuous deionization from ultrapure water production on the regeneration of surface engineering and metalworking systems is not known.

The Electrodeionization technology for surface engineering and metal industry differs from pure water production in many parameters and needed new approaches and design concepts.

One important difference is the composition of the treated Water and the resulting physical properties. For the production of ultrapure water by electrodeionization (Stendten, D .; Leyer, D .: ultrapure water deionization and ultrapure water systems, Laboratory Technology II (2001), p. 28 ff) You usually get a water that already with the help of a reverse osmosis on a conductivity of about 10-20 μS / cm and a neutral pH was pre-cleaned. Located in rinsing waters In contrast, components of electroplating baths, for example, ions of different Salts and acids, which the conductivity significantly increase the water. In general, the conductivity values of the rinse water much bigger in comparison with the effective conductivity of the ion exchange material, especially in the case of the selective Ion exchangers. This results in a preferred ion migration in electric field is not preferred by the ion exchange material, but through the electrolyte, which is between the ion exchanger particles (Vuorilehto, K., Tamminen, A .: Application of a solid ion-exchange electrolyte in three-dimensional electrodes, Journ. of Applied Electrochemistry 27 (1997), pp. 749-755). This can be the process efficiency reduce to zero. To a transfer of adsorbed ions in the deionized solution Therefore, you should not in appropriate cases a simultaneous, but a consecutive adsorption and electrochemical ion exchanger regeneration at short intervals aspire.

• 1. Der Zellaufbau hat eine extrem ungünstige Anolytführung zur Folge. Dies führt bei einer Regenerierung zu Problemen, weil an den Elektroden gebildete Spezies, H⁺-und OH^--Ionen, nur durch die Separatoren in den Ionenaustauscherraum wandern können. Dies reduziert sehr stark die Effektivität der Regenerierung und führt zu einer ernorm erhöhten Zellspannung und zu sehr langen Regenerierungszeiten.
• 2. Die Katholyt und Anolyt trennende Membranen verursachen zusätzliche Spannungsabfälle.
• 3. Die Anordnung von mehreren Elektrodenkammern zwischen nur zwei Elektroden kann erstens zur schlechten Stromverteilung in der Zelle führen, (Wegfall der Regenerierung in den mittleren Ionenaustauscherkammern) und zweitens zum Mangel an Spezies (H⁺- und OH^--Ionen), die für die Ionenaustauscherregenerierung benötigt werden.
• 4. Ohne eine zusätzliche pH-Wert Korrektur kann der pH-Wert im Katholytwegen einer ungünstigen Elektrolytstromführung schnell steigen und zur Hydroxidbildung führen. Dadurch können sehr große Zellspannungen auftreten; die Zelle kann verstopfen und außer Betrieb gehen.

From the DE 40 16 000 C2 In contrast, it is only an apparatus for the treatment of metal-containing liquids by ion exchange and regeneration of the ion exchange material with the aim of energy saving and metal recovery in solid form with preference the principle of electrodialysis known as effect effect. As already mentioned, simultaneous ion exchanger regeneration is not possible for surface engineering systems. For periodic regeneration of the ion exchanger this device is not usable. The reasons for this are:

• 1. The cell structure results in an extremely unfavorable Anolytführung. This leads to problems in a regeneration because species formed on the electrodes, H ⁺ and OH ^- ions, can only migrate through the separators into the ion exchange space. This greatly reduces the effectiveness of the regeneration and leads to a tremendously increased cell voltage and to very long regeneration times.
• 2. The catholyte and anolyte separating membranes cause additional voltage drops.
• 3. The arrangement of several electrode chambers between only two electrodes can lead firstly to poor current distribution in the cell (elimination of regeneration in the middle ion exchange chambers) and secondly to the lack of species (H ⁺ and OH ^- ions) which are responsible for the Ion exchanger regeneration are needed.
• 4. Without an additional pH correction, the pH in the catholyte may increase rapidly due to unfavorable electrolyte flow and lead to hydroxide formation. As a result, very large cell voltages can occur; The cell can become clogged and out of service.

From the DE 44 18 812 C2 An electrochemical cell for the electrodeionization of aqueous solutions has become known, in which both electrode spaces are filled with the ion exchanger, between which, separated by membrane, there is a concentration space. It is advantageous in this case that the H ⁺ or OH ^- ions necessary for the regeneration of the ion exchange beds are produced directly in the ion exchange bed. However, the cell operates continuously and is unsuitable for the treatment of heavy metal systems from surface treatment due to the transfer of adsorbed ions into the resulting solution and possible deposition and calcination reactions at the cathode, as well as possible chlorine evolution at the anode.

aim The invention is to provide a method which has the disadvantages the known Elektroentionisierungsverfahren for the preparation of in chemical and / or electrochemical surface treatment Rinsing waters produced by metals a proportion of heavy metals in anion and / or cation form avoids and the environmental compatibility the process by reducing the amount of waste solutions, which must be disposed of costly, decisively improved.

The object is a process for the treatment of metal-containing liquids used in the surface treatment of metals, in particular in the electroplating and erosive processes such as pickling, etching, firing, etc., but also in the workup of metal-containing residues from chemistry, metallurgy and Environmental technology arise and accumulate with cations or anions of heavy metals to provide by ion exchange and periodic regeneration of the ion exchange material by electrodialysis in preferably an apparatus unit. According to the invention, the object is achieved by an electrodeionization process for the treatment of rinsing waters produced in the chemical and / or electrochemical surface treatment of metals with a proportion of heavy metals in anion and / or cation form and with other constituents of process baths, the purification of the metal-containing liquids by ion exchangers and periodic regeneration of the ion exchange resin by electrodialysis with applied voltage or by means of current flow, and is characterized in that for a cell of at least two sub-cells is used, which is separated by at least one separator, which is formed as a diaphragm and / or ion exchange membrane , Wherein at least two sub-cells receive a differently polarized electrode (anode or cathode), and at least one of the sub-cells, preferably the cathode space, receives an ion-exchange material, which with the Elek in direct contact that electrochemically species of H ⁺ or OH ^- ions are formed for the regeneration of the ion exchange material and that further in the currentless load case of the ion exchange material, a material flow is realized by the ion exchange material, and temporally consecutive regeneration is carried out in such a way by a stream of material is passed in a separate cycle or continuously through the ion exchange material and a second material or liquid stream flows through the other, an electrode receiving subcell.

• 1. Das behandelte Spülwasser kann wiederverwendet oder leicht entsorgt werden. Es kann eine Senkung der Metallkonzentrationen, z.B. in Spülen bis auf 0,1 mg/l, erreicht werden.
• 2. Diese Technologie kann an Standspülen angeschlossen werden, um dort eine niedrige Konzentration von Schwermetallen und anderen Inhaltsstoffen einzuhalten.
• 3. Während der Regenerierung des Ionenaustauschers entsteht ein Konzentrat von Schwermetallen in Form von Säure-, Hydroxid- und Salzlösungen. Dieses Konzentrat kann man bedeutend leichter im Vergleich mit der verdünnten Lösung weiterverwenden bzw. nützlicherweise für Bäderkorrekturen bezüglich der rückgewonnenen Schwermetalle einsetzen. Eine derartige Vorgehensweise ist besonders interessant für Metallionen mit schwerer elektrochemischer Abscheidbarkeit (Chromsysteme). Üblicherweise aus konventionellen Ionenaustauschern erhaltene Cr(III)-Lösungen sind für Badkorrekturen nicht geeignet.
• 4. Durch die elektrochemische Regenerierung des Ionenaustauschermaterials kann die Abwasserbildung minimiertwerden.
• 5. Das Verfahren ist gleichfalls für eine effektive Reinigung von Fließ- bzw Spritzspülwässern bzw. Systemen mitvergleichsweise geringer Konzentration geeignet.
• 6. Durch die Spezifik des Verfahrens lässt sich im Vergleich zum konventionellen Ionenaustausch die benötigte Ionenaustauschermenge um z.B. eine Größenordnung verringern.

Essentially, the following results should be achieved:

• 1. The treated rinse water can be reused or disposed of easily. It can be a reduction in metal concentrations, for example, in rinses to 0.1 mg / l, can be achieved.
• 2. This technology can be connected to stationary rinses to maintain a low concentration of heavy metals and other ingredients.
• 3. During the regeneration of the ion exchanger, a concentrate of heavy metals in the form of acid, hydroxide and salt solution is formed This concentrate can be used much more easily in comparison with the dilute solution, or it can be usefully used for bath corrections with respect to the recovered heavy metals. Such a procedure is particularly interesting for metal ions with heavy electrochemical precipitability (chromium systems). Commonly obtained from conventional ion exchangers Cr (III) solutions are not suitable for Badkorrekturen.
• 4. The electrochemical regeneration of the ion exchange material can minimize wastewater formation.
• 5. The method is also suitable for effective cleaning of flow or splash rinses or comparatively low concentration systems.
• 6. Due to the special nature of the process, the required amount of ion exchanger can be reduced by, for example, one order of magnitude compared to conventional ion exchange.

Farther can be a direct adaptation of modules and process control to different amounts of solution and concentrations either through the use of multiple unit cells and / or electrical interconnections of corresponding cell units in parallel or in series (e.g., by bipolar electrodes and / or a bipolar membrane) or by an optimized flushing water and electrolyte flow guide both in ion exchange as well as in the ion exchanger regeneration. For simultaneous or periodic metal deposits and / or concentrations as well pH corrections can be made to the electrodeionization module, directly to the concentration chamber or to the concentration tank, one Deposition device or an electrodialysis be switched on. For one optimum concentration of heavy metals or other components of the solution can in each cell unit several instead of one concentration chamber Concentration chambers next to each other as in a stack electrodialysis to be built in. This means, the inventive method let yourself by repeating in variable-size stack designs.

There the proposed electrodeionization process two consecutive Processes - ion exchange and electrochemical ion exchanger regeneration - has, should of course both processes possible precise Timed to each other or individually optimized. For one concrete ion exchange are different ion exchange materials used. Furthermore, a treated water may be the ion exchange chambers flow through parallel and / or consecutively. For effective removal of heavy metal ions from waters with a proportion of other ions, e.g. Calcium, magnesium, Sulfate, phosphate, chloride or other, is a use of selective ion exchangers or a combination of them with e.g. other strongly acidic or strongly basic ion exchangers required. Around To reduce the number of modules, the loading of ion exchangers by an increase the convection as well as an increase the temperature of the treated system are accelerated. equilibria in ion exchange are highly dependent on pH values. That's why it is useful, always special ion exchangers or their combination as well as optimal Material flow guides to consider. In the case of a neutral water, selectively separated from the anions It is an advantage to first use the water to be purified Lowering the pH by a strongly acidic ion exchanger and then by a selective To conduct anion exchanger. Another embodiment describes the increase of Efficiency of ion exchange with simultaneous cationic and anion removal. Here, the water to be treated with a pH in the acidic range, first by an anion exchanger and then passed through a cation exchanger. The reverse applies for waters with basic pH.

The following aspects are interesting for effective electrochemical ion exchanger regeneration. Species formed at the electrodes and responsible for ion exchange regeneration, OH ^- and H ⁺ ions, must react directly with the ion exchanger or be exchanged with charged ions. This can be done on the one hand by a common placement of the ion exchanger and an electrode in the same cell space (eg, cation exchanger in the anode compartment and anion exchanger in the cathode compartment) or on the other hand by a common circuit for the anode chamber and cation exchange chambers and / or cathode chamber and anion exchange chambers during regeneration. In the first case, a simplified cell unit with fewer membranes and cell spaces is available. This results in easier operation as well as lower cell voltages and lower energy costs. In the second case, a better degassing can be realized. As a result, it is possible to work with higher current intensities, which leads to a shortening of the regeneration times. In addition, with regard to the cell structure and the guidance of electrolyte flows through the chambers of the cell, there are, of course, many more possibilities for conducting the method, as can be seen from the embodiments of the method according to the invention described below.

To prevent the development of toxic chlorine gas, an anolyte should be used as an anolyte free from chloride. This can be on an additional The cation exchange membrane in front of the anode can be dispensed with, which, in addition to saving the costs for the membrane, also leads to a simplified construction and lower energy costs. Furthermore, the process solutions can be added to the conductivity-increasing chemicals to reduce the cell voltage or to increase cell current and current efficiency. For this, bases, acids, salts as well as special buffer solutions that prevent the failure of metal hydroxides or metal deposits can be used. To prevent metal deposits or limescale deposits at the cathode, a bipolar membrane or an anion exchange membrane should be located in front of the cathode in the cation chamber.

With The invention became a solution found a quasicontinuous regeneration of process waters of the surface technology and metalworking and processing industry etc. by means of a clocked deionization content. By the method according to the invention can lower the heavy metal concentration in rinsing up 0.1 mg / l can be achieved. The heavy metals and other bath components are concentrated in anionic and / or cationic form and can as Concentrate for a process bath correction can be used. This allows a wastewater and sludge formation are prevented. The energy expenditure is in the Compared to electrodialysis greatly reduced.

The 1 to 8th illustrate preferred embodiments of the method according to the invention.

1 Figure 3 illustrates a clocked electrodeionization process with a dual-compartment cell that serves to separately remove anions or cations that are not electrochemically reactive at the anode and / or cathode.

2 shows an electrodeionization process using a cell consisting of at least three sub-cells 1 . 2 and 7 passing through at least two separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, wherein at least two sub-cells 1 . 2 differently polarized electrodes, anode 9 and cathode 10 , absorb as well as with an ion exchange material 12 filled with the anode 9 and the cathode 10 is in direct contact with electrochemical species of H ⁺ or OH ^- ions for regeneration of the ion exchange material 12 are formed, and further in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through the ion exchange material 12 is realized, in parallel or successively through the cathode chamber 2 and the anode chamber 1 is passed, and temporally consecutive regeneration is carried out such by a liquid flow 15 in a separate circuit or continuously through the anode chamber 1 and a liquid stream 14 through the cathode chamber 2 is passed, and one by two sequential separators 8th resulting subcell 7 an electrodialytic concentration chamber function takes over and prevents unwanted electrode reactions and in the ion exchanger regeneration its own liquid flow 16 has. The liquid streams 13 . 14 . 15 and 16 be by means of pumps 29 . 30 . 31 and 32 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 . 23 and 24 pumped and returned to this. In this embodiment of the method according to the invention, cations and anions are concentrated without separation. This creates a concentrate that contains important constituents of the process bath, ie consists of salts of heavy metals and acids and is usable for a process bath correction. Preferred applications of this embodiment of the invention are the cleaning of rinses from surface technology, for example, from the nickel plating, copper plating, among others

3 Figure 1 illustrates an electrodeionization process in which at least four sub-cells 1 . 2 . 3 and 4 containing cell is used by at least two separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, wherein at least two sub-cells 1 and 2 record differently polarized electrodes, anode 9 and cathode 10 , wherein at least two of the sub-cells 3 and 4 associated with different electrodes, different ion exchange material 12 and lie next to each other and through a bipolar membrane or a bipolar electrode 11 are separated from each other that the ion exchange materials 12 with the two poles of the bipolar membrane or the bipolar electrode 11 are in direct contact with electrochemical species of H ⁺ or OH ^- ions for regeneration of the ion exchange material 12 be formed and continue in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through both ion exchange subcells 3 and 4 is realized in parallel or in succession, and temporally consecutive regeneration is carried out in such a way by two autonomous liquid streams 17 and 18 for regeneration of the ion exchange materials 12 in a separate circuit or continuously through the ion exchange subcells 4 and 3 be routed through separators 8th at the ion exchange subcells 3 and 4 adjacent electrode sub-cells 1 and 2 Concentration functions take over and at the ion exchanger regeneration at least two separate liquid circuit runs 15 and 14 have. The liquid streams 13 . 14 . 15 . 17 and 18 be by means of pumps 29 . 30 . 31 . 34 and 35 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 . 23 . 26 and 27 be pumped and returned to this again. The embodiment of the method is preferably used for the regeneration of rinsing waters, which arise in abrasive metal processes, such as pickling, etching, firing, among others. Here, removed foreign metal ions are separated and concentrated to solutions useful for bath correction. As a typical example may be mentioned the regeneration of aluminum resulting from the chromium plating process waters. By deionization, for example, a sink of aluminum and chromium ions is cleaned, after the regeneration in the anolyte concentrated chromic acid can be reused for a process bath correction, whereas in the catholyte concentrated aluminum ions can be easily disposed of.

4 shows an electrodeionization process in which one at least five sub-cells 1 . 2 . 3 . 4 and 5 containing cell is used by at least three separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, and at least two sub-cells 1 and 2 record differently polarized electrodes, anode 9 and cathode 10 , wherein at least two of the sub-cells 3 and 4 associated with different electrodes, different ion exchange material 12 take up, lie next to each other and through a bipolar membrane or a bipolar electrode 11 are separated from each other that the ion exchange materials 12 with the two poles of the bipolar membrane or the bipolar electrode 11 are in direct contact with electrochemical species of H ⁺ or OH ^- ions for regeneration of the ion exchange material 12 be formed and another subcell 5 between an ion exchange subcell 3 and the anode chamber 1 and from them through two separators 8th is separated and in the regeneration an electrodialytic concentration chamber function or a concentration chamber and protective function against unwanted electrode reactions takes over, further in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through both ion exchange cells 3 and 4 is realized, and temporally consecutive regeneration is carried out by two autonomous liquid streams 17 and 18 in a separate circuit through the ion exchange cells 4 and 3 be routed through separators 8th at the ion exchange cells 3 and 4 adjacent subcells 2 and 5 perform a concentration function and in the ion exchanger regeneration at least two separate liquid streams 14 and 16 own and another fluid stream 15 autonomously the anode chamber 1 flows through. The liquid streams 13 . 14 . 15 . 16 . 17 and 18 be by means of pumps 29 . 30 . 31 . 32 . 34 and 35 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 . 23 . 24 . 26 and 27 be pumped and returned to this again.

The Method is preferred for the regeneration of rinse waters, the in ablative metal processes, such as pickling, etching, firing, etc., or after Metal deposition processes, such as the chromating arise, used. Here, removed foreign metal ions are separated or for a bath correction useful solutions concentrated. additionally allows this embodiment of the method a prevention of unwanted cathode or anode reactions while regeneration, e.g. a metal deposition or chlorine evolution. A typical application is the treatment of after chrome plating of copper alloys resulting rinse waters. By deionization is e.g. a sink purified from copper and chromium ions; after regeneration in anolyte concentrated chromic acid Can be reused for process bath correction and concentrated in concentration chambers Copper and tin ions can recovered become. Another application is the treatment of chloride-containing Rinsing waters, the when metal pickling of titanium or aluminum arise.

5 FIG. 12 illustrates an electrodeionization process in which at least three sub-cells 1 . 2 and 3 containing cell is used by at least two separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, wherein at least two sub-cells differently polarized electrodes, anode 9 or cathode 10 , record, wherein at least one of the sub-cells 3 , which is located between two electrode spaces, with an ion exchange material 12 is filled with one of the other electrode spaces a common fluid circuit 14 has, so that electrochemically formed species of H ⁺ or OH ^- ions in the ion exchange material 12 be transported and continue in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through the ion exchange material 12 is realized, and temporally consecutive regeneration is carried out in such a way by a liquid flow 14 in a separate circuit through the ion exchange chamber 3 and cathode chamber 2 parallel or sequentially, and a second liquid stream 15 through the anode chamber 1 flows. The liquid streams 13 . 14 and 15 be by means of pumps 29 . 30 and 31 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 and 23 be pumped and returned to this again. This Ausgestal tion of the procedure is, as in 1 illustrated embodiment for a separate removal of anions or cations, which do not react electrochemically at the anode and / or cathode determined. However, this variant has better degassing options. It can therefore be worked with a larger cell stream, whereby a faster regeneration is achieved.

6 shows an electrodeionization process in which one at least four sub-cells 1 . 2 . 3 and 7 containing cell is used by at least three separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, wherein at least two sub-cells 1 and 2 record differently polarized electrodes, anode 9 or cathode 10 , wherein at least one of the sub-cells 3 , which is located between two electrode spaces, with an ion exchange material 12 filled with the cathode compartment 2 a common fluid circuit 14 has, so that electrochemically formed species of OH ^- ions in the ion exchange material 12 be transported to its regeneration, and another subcell 7 Concentration functions or a concentration and protective function against unwanted electrode reactions takes over and unwanted desired electrode reactions prevented and in the ion exchange regeneration of a separate liquid stream 16 is flowed through, further in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through the ion exchange material 12 is realized, and temporally consecutive regeneration is carried out such by a liquid flow 14 in a separate circuit through the ion exchange subcell 3 and the cathodic chamber 2 is passed and a second liquid stream 15 the anode chamber 1 flows through. The liquid streams 13 . 14 . 15 and 16 be by means of pumps 29 . 30 . 31 and 32 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 . 23 and 24 be pumped and returned to this again.

These Embodiment of the method according to the invention is a universal variant for the separate removal of anions or cations that are electrochemical at the anode or cathode react, is applicable, as e.g. in the removal of chloride and fluoride ions or heavy metals such as copper, nickel, tin and the like, the case is.

7 shows an electrodeionization process in which one of at least three sub-cells 1 . 2 and 7 existing cell is used by at least two separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, wherein at least two sub-cells 1 and 2 record differently polarized electrodes, anode 9 or cathode 10 , wherein at least one of the sub-cells, preferably the cathode space 2 , with an ion exchange material 12 filled with the cathode 10 is in direct contact with electrochemical species of OH ^- ions for regeneration of the ion exchange material 12 be formed and continue in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through the ion exchange material 12 is realized, and temporally consecutive regeneration is carried out in such a way by a liquid flow 14 in separate circulation through the ion exchange material 12 is passed and a second liquid stream 15 through the anode chamber 1 and at least one, by at least two sequential separators 8th resulting subcell 7 an electrodialytic concentration chamber function or concentration and protective function against unwanted electrode reactions takes over and in the ion exchanger regeneration of a separate liquid stream 16 is flowed through. The liquid streams 13 . 14 . 15 and 16 be by means of pumps 29 . 30 . 31 and 32 powered by the appropriate fluids from the electrolyte reservoirs 21 . 22 . 23 and 24 be pumped and returned to this again.

This embodiment of the invention is analogous to 6 illustrated embodiment used.

8th shows an electrodeionization process in which one of at least six sub-cells 1 . 2 . 3 . 4 . 5 and 6 existing cell is used by at least four separators 8th , which are formed as a diaphragm and / or ion exchange membrane, are separated from each other, and at least two sub-cells 1 and 2 record differently polarized electrodes, anode 9 or cathode 10 , wherein at least two of the sub-cells 3 and 4 associated with different electrodes, with different ion exchange material 12 filled and juxtaposed and by a bipolar membrane or a bipolar electrode 11 are separated from each other and the ion exchange materials 12 with both poles of the bipolar membrane or the bipolar electrode 11 are in direct contact with electrochemical species of H ⁺ or OH ^- ions for regeneration of the ion exchange material 12 be formed and at least two further sub-cells 5 and 6 between an ion exchange chamber 3 . 4 and an electrode chamber 1 . 2 and from them through two separators 8th are separated and take over in the regeneration of an electrolytic concentration function or concentration and protection against unwanted electrode reactions, continue in the currentless load case of the ion exchange material 12 a rinse water liquid stream 13 through both ion exchange subcells 3 and 4 is realized in parallel or in succession, and temporally consecutive regeneration is carried out in such a way by two autonomous liquid streams 17 and 18 in a separate circuit through the Ionenaustauscherteilzellen 3 and 4 be routed through separators 8th to the ion exchange subcells 3 and 4 adjacent subcells 5 and 6 Take over concentration functions and in the ion exchanger regeneration of at least one separate liquid flow 16 . 19 be flowed through and at least one other liquid stream 20 the anode chamber 1 and the cathodic chamber 2 flows through in parallel or in succession. The liquid streams 13 . 16 . 17 . 18 . 19 and 20 be by means of pumps 29 . 32 . 33 . 34 . 35 and 36 powered by the appropriate fluids from the electrolyte reservoirs 21 . 24 . 25 . 26 . 27 and 28 be pumped and returned to this again. This embodiment of the method can preferably be used for the regeneration of rinsing waters, which are formed in ablative metal processes, such as pickling, etching, firing, etc., by removing ions which can react electrochemically at the anode or cathode. Here, removed foreign metal ions are separated or concentrated to solutions useful for bath corrections. An application of the method can be carried out, for example, in the treatment of chloride-containing rinses, which arise after metal pickling of copper and its alloys.

The inventive method as well as its advantageous effects are described below embodiment further explained become.

Here, the treatment of a resulting after chroming rinse water with a content of 60 mg [Cr (VI)] / l, 12 mg [Cl ^- ] / l, 50 mg [SO 2 4 ] / L and a pH of 2.91.

In this electrodeionization process, as in 1 shown an anion exchange material 12 directly into the cathode chamber 2 filled. anode chamber 1 and cathode chamber 2 are separated from each other by a diaphragm 8th separated. The cathode chamber 2 is with a chromium selective ion exchange material 12 filled with the brand name "Lewatit Monoplus MP 64" in the OH ^- form and a mass of about 55 g 10 a titanium plate electrode (18 mm × 140 mm) is used. As an anode 9 serves a platinum-plated titanium electrode (18 mm × 150 mm). When carrying out the process, ion exchange and electrochemical ion exchanger regeneration occur successively. By pump 29 gets out of an electrolyte container 21 with a volume of 16 l a rinse water stream 13 through the cathode space 2 promoted. The throughput is 0.6 l / min over a period of 3 h. This reduces the chromium ion concentration in the 16 l rinse water 60 mg / l to 2 mg / l and a capacity of the ion exchange material 12 of about 16.9 g [Cr (VI)] / kg of ion exchange material 12 reached. The purified rinse water had a pH of 6.1 and has concentrations of 37 mg [SO 2 4 ] / L and 7 mg [Cl ^- ] / l. It can be used again for rinsing purposes.

The ion exchange is followed by an electrochemical ion exchanger regeneration. The electrolytic cell unit is operated with a current of 0.35 A for 4 h. During this time is by means of the pump 31 from the electrolyte container 23 a liquid stream 15 through the Annodenkammer 1 and at the same time by means of the pump 30 from the electrolyte container 22 a liquid stream 14 through the cathode chamber 2 promoted. The flow rates of the liquid streams 14 and 15 each amount to approx. 0.3 l / min. The liquid flow 14 consists of a 0.01 M NaOH and the liquid stream 15 from the rinse water liquid having a Cr (VI) concentration of 60 mg / L and a pH of 2.9. During regeneration, hexavalent chromium migrates into the anode chamber 1 and concentrate there. This results in a concentrate having a Cr (VI) concentration of 1.71 g / l and a pH of 1.5 after regeneration. The ion exchange material 12 is regenerated to 89%. The average current efficiency of the regeneration, based on CrO 2 4 ions , is about 60%.

The "ion exchange - ion exchanger regeneration" cycle is carried out five times without changing the electrolyte liquids, and only electrolysis and aerosol discharge result in reduced electrolyte volumes in the liquid streams 14 and 15 compensated by adding rinse water liquid. For the ion exchange each new 16 l rinse water from a chromating are used. After each ion exchange, the Cr (VI) concentration in the treated rinse water drops from 60 mg / L to 2-3 mg / L. After 5 cycles, a concentrate with a concentration of Cr (VI) ions of 10.2 g / l, on SO 2 4 ions of 1.2 g / l and Cl ^- ions of 0.12 g / l and a pH of 1.12. This concentrate can be reused to correct the chromating bath.

1

subcell (Anode chamber)

2

subcell (Cathode chamber)

3, 4, 5, 6, 7

partial cells

8th

separator

9

anode

10

cathode

11

bipolar Membrane or bipolar electrode

ion exchange

13

Spülwasserflüssigkeitsstrom

14

liquid flow through the cathode chamber

15

liquid flow through the anode chamber

16 19

Liquid flows through the seperator chambers

17 18

Liquid streams for regeneration the ion exchange materials

20

liquid flow through the anode and cathode chamber

21-28

electrolyte container

29-36

pump to promote the liquid streams

Claims (15)

Electrodeionization process for the treatment of rinsing waters produced by both chemical and / or electrochemical surface treatment of metals containing a proportion of heavy metals in anionic and / or cationic form and with other constituents of process baths, comprising purification of the metal-containing liquids by ion exchangers and periodic regeneration of the ion exchange material ( 12 ) by electrodialysis, characterized in that the preparation in one of at least two sub-cells ( 1 and 2 ) existing cell, which is separated by at least one separator ( 8th ), which is formed as a diaphragm and / or ion exchange membrane are separated, wherein at least two sub-cells as differently polarized electrode an anode ( 9 ) or cathode ( 10 ) and at least one of the electrode accommodating partial cells an ion exchange material ( 12 ), which is in direct contact with the electrode, that electrochemically contains species of H ⁺ or OH ^- ions for the regeneration of the ion exchange material ( 12 ) and that in the currentless load case of the ion exchange material ( 12 ) a Spülwasserfütsigkeitsstrom ( 13 ) is realized by the bed, and temporally consecutive regeneration is carried out in such a way by a liquid flow ( 14 ) in separate circulation or continuously through the ion exchange material ( 12 ) and a second liquid stream ( 15 ) flows through the other, an electrode receiving subcell. Method according to claim 1, characterized in that that single cell systems for the process operation combined into a complex unit become. A method according to claim 1, characterized in that with ion exchange material ( 12 ) filled partial cells ( 1 . 2 . 3 . 4 ) Absorb cation and / or anion exchange material. Method according to claim 1, characterized in that that several procedures At least in one of the consecutive stages ion exchange and / or Regeneration at least for individual liquid streams in parallel or run one after the other. Method according to claim 1, characterized in that that the individual consecutively proceeding partial stages exchange ions and regeneration are performed according to a predetermined timing scheme. Method according to claim 1, characterized in that that while consecutive stages of ion exchange and regeneration a parameter of operation, such as throughput rate of a liquid stream, amperage or cell voltage, temperature or subcircuit composition, changed over time becomes. Method according to Claims 1 and 2, characterized that sub-cells electrically parallel or in series apparatus or by a bipolar electrode and / or a bipolar membrane electrically be switched. Method according to claim 1, characterized in that that for simultaneous or periodic metal deposits and / or concentrations as well as pH corrections to the electrodeionization module directly to a concentration chamber or to a concentration tank one Deposition device or an electrodialysis be switched on. Method according to claim 1 to 8, characterized in that the cell consists of at least three sub-cells ( 1 . 2 and 7 ) by at least two separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) differently polarized electrodes, anode ( 9 ) and cathode ( 10 ) and with an ion exchange material ( 12 ) filled with the anode ( 9 ) or cathode ( 10 ) is in direct contact with electrochemical species of H ⁺ or OH ^- ions for regeneration of the ion exchange material ( 12 ) and that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) by the ion exchange material ( 12 ) realized in parallel or successively through the cathode chamber ( 2 ) and the anode compartment ( 1 ), and temporally consecutive regeneration is carried out in such a way by a liquid flow ( 15 ) in a separate circuit or continuously through the anode chamber ( 1 ) and a liquid flow ( 14 ) through the cathode chamber ( 2 ) and at least one by at least two sequential separators ( 8th ) subcell ( 7 ) an electrodialysis cal concentration chamber function and prevents unwanted electrode reactions and in the ion exchanger regeneration its own liquid flow ( 16 ) owns. Method according to claims 1 to 8, characterized in that the cell consists of at least four partial cells ( 1 . 2 . 3 and 4 ) by at least two separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) receive differently polarized electrodes, anode ( 9 ) and cathode ( 10 ), wherein at least two of the sub-cells ( 3 and 4 ) are assigned to different electrodes, different ion exchange material ( 12 ) and lie next to each other and through a bipolar membrane or a bipolar electrode ( 11 ) are separated from each other, that the ion exchange materials ( 12 ) with the two poles of the bipolar membrane or the bipolar electrode ( 11 ) are in direct contact with electrochemical species of N ⁺ or OH ^- ions for regeneration of the ion exchange material ( 12 ) and that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) through both ion exchange subcells ( 3 and 4 ) is realized in parallel or successively, and a consecutive regeneration is carried out such that two autonomous liquid streams ( 18 and 17 ) in a separate circuit through the ion exchange partial cells ( 3 and 4 ) and separated by separators ( 8th ) at the ion exchange subcells ( 3 and 4 ) adjacent electrode subcells ( 1 and 2 ) And at least two separate liquid streams in the ion exchanger regeneration ( 15 and 14 ). Method according to claim 1 to 8, characterized in that the cell consists of at least five sub-cells ( 1 . 2 . 3 . 4 and 5 ) separated by at least three separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) receive differently polarized electrodes, anode ( 9 ) and cathode ( 10 ), wherein at least two of the sub-cells ( 3 and 4 ) are assigned to different electrodes, different ion exchange material ( 12 ), lie next to each other and through a bipolar membrane or a bipolar electrode ( 11 ) are separated from each other, that the ion exchange materials ( 12 ) with the two poles of the bipolar membrane or the bipolar electrode ( 11 ) are in direct contact that electrochemically species of H ⁺ - or OH ^- ions for the regeneration of the ion exchange material ( 12 ), that at least one further subcell ( 5 ) between an ion exchange subcell ( 3 ) and the anode chamber ( 1 ) and separated from them with two separators ( 8th ) is separated and in the regeneration an electrodialytic concentration chamber function or a Konzentrationskammer- and protective function against unwanted electrode reactions takes over that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) through both ion exchange subcells ( 3 and 4 ) is realized in parallel or successively, and a consecutive regeneration is carried out such that two autonomous liquid streams ( 18 and 17 ) in a separate circuit through the ion exchange partial cells ( 3 and 4 ) and separated by separators ( 8th ) at the ion exchange subcells ( 3 and 4 ) adjacent subcells ( 2 and 5 ) And at least two separate liquid streams during ion exchanger regeneration ( 16 and 14 ) and another liquid stream ( 15 ) autonomously through the anode chamber ( 1 ) or two streams of liquid passing through the anode chamber ( 1 ) and the cathode chamber ( 2 ), be reduced to a common liquid flow. Method according to claim 1 to 8, characterized in that the cell consists of at least three sub-cells ( 1 . 2 and 7 ) by at least two separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) receive differently polarized electrodes, anode ( 9 ) or cathode ( 10 ), and at least one of the electrode cells accommodating an electrode ( 1 or 2 ) an ion exchange material ( 12 ), which is in direct contact with the electrode, that electrochemically contains species of H ⁺ or OH ^- ions for regeneration of the ion exchange material ( 12 ) and that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) by the ion exchange material ( 12 ) is realized, and temporally consecutive regeneration is carried out such that a liquid flow ( 14 ) in separate circulation through the Ionenaustauschermateri al ( 12 ) and a second liquid stream ( 15 ) is conveyed through the other, an electrode receiving subcell and at least one by at least two successive separators ( 8th ) subcell ( 7 ) performs an electrodialytic concentration chamber function or concentration and protective function against unwanted electrode reactions and in the ion exchanger regeneration of a separate liquid flow ( 16 ) is flowed through. Method according to claim 1 to 8, characterized in that the cell consists of at least six partial cells ( 1 . 2 . 3 . 4 . 5 and 6 ) separated by at least four separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) receive differently polarized electrodes, anode ( 9 ) or cathode ( 10 ), wherein at least two of the sub-cells ( 3 and 4 ) are assigned to different electrodes, different Io exchange material ( 12 ) and lie next to each other and through a bipolar membrane or a bipolar electrode ( 11 ) are separated from each other, that the ion exchange materials ( 12 ) with the two poles of the bipolar membrane or the bipolar electrode ( 11 ) are in direct contact that electrochemically species of H ⁺ - or OH ^- ions for the regeneration of the ion exchange material ( 12 ), that at least two further sub-cells ( 5 and 6 ) between an ion exchange cell ( 3 or 4 ) and an electrode chamber ( 1 or 2 ) and from them with two separators ( 8th ) are separated and in the regeneration an electrolytic concentration function or concentration and protection function against unwanted electrode reactions take, continue in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) through both ion exchange cells ( 3 and 4 ) is realized in parallel or successively, and a consecutive regeneration is carried out such that two autonomous liquid streams ( 18 and 17 ) in a separate circuit through the ion exchange cells ( 3 and 4 ) and separated by separators ( 8th ) to the ion exchange cells ( 3 and 4 ) adjacent subcells ( 5 and 6 ) And at least two separate liquid streams in the ion exchanger regeneration ( 16 and 19 ) and at least one further liquid stream ( 20 ) the anode chamber ( 1 ) and the cathode chamber ( 2 ) flows through in parallel or in succession. Electrodeionization process for the treatment of rinsing waters in the chemical and / or electrochemical surface treatment of metals containing a proportion of heavy metals in anionic and / or cationic form and with other constituents of process baths, comprising purification of the metal-containing liquids by ion exchangers and periodic regeneration of the ion exchange material ( 12 ) by electrodialysis, characterized in that the cell consists of at least three sub-cells ( 1 . 2 and 3 ) by at least two separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) differently polarized electrodes, anode ( 9 ) or cathode ( 10 ), wherein at least one of the sub-cells ( 3 ) located between two electrode chambers ( 1 and 2 ), an ion exchange material ( 12 ), through which as well as by one of the electrode chambers ( 1 or 2 ) a common liquid stream ( 14 ), the electrochemically formed species of N ⁺ or OH ^- ions in the ion exchange material ( 12 ) and that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) by the ion exchange material ( 12 ) is realized, and temporally consecutive regeneration is carried out such that a liquid flow ( 14 ) in a separate circuit or continuously through the ion exchange chamber ( 3 ) and the cathode chamber ( 2 ) is passed in parallel or in succession, and a second liquid stream ( 15 ) through the anode chamber ( 1 ). Method according to claim 14, characterized in that the cell consists of at least four partial cells ( 1 . 2 . 3 and 7 ) separated by at least three separators ( 8th ) are separated from each other, wherein at least two sub-cells ( 1 and 2 ) receive differently polarized electrodes, anode ( 9 ) or cathode ( 10 ), wherein at least one of the sub-cells ( 3 ) located between two electrode chambers ( 1 and 2 ), an ion exchange material ( 12 ), through which as well as by one of the electrode chambers ( 1 or 2 ) a common liquid stream ( 14 ), the electrochemically formed species of H ⁺ or OH ^- ions in the ion exchange material ( 12 ), and another subcell ( 7 ) Takes over concentration functions or concentration and protective function against unwanted electrode reactions and prevents undesired electrode reactions and in the ion exchanger regeneration its own liquid flow ( 16 ), and that in the currentless load case of the ion exchange material ( 12 ) a rinse water liquid stream ( 13 ) by the ion exchange material ( 12 ) is realized, and temporally consecutive regeneration is carried out such that a liquid flow ( 14 ) in a separate circuit through the ion exchange cell ( 3 ) and the cathode chamber ( 2 ) is passed in parallel or in succession and a second liquid stream ( 15 ) through the anode chamber ( 1 ).