Method and dissolving station for dissolving metallic nickel in electrolytes
Patent Information
- Application Number
- PCT/EP2026/053510
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-24
- Filing Date
- 2026-02-10
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026053510_27082026_PF_FP_ABST
Abstract
Description
[0001] METHOD AND SOLUTION STATION FOR SOLIDING METALLIC NICKEL IN ELECTROLYTES
[0002] The subject matter of this invention is a method for dissolving metallic nickel, in particular metallic nickel pellets or nickel granules, in electrolytes used for the electrolytic coating of metal substrates, for example steels or metal strips, with nickel in a coating system. The subject matter of the invention also includes an apparatus for carrying out the method.
[0003] In a continuous electrolytic coating line for nickel-coated steels, such as those intended for the production of battery casings, nickel must be continuously replenished in the electrolyte. This ensures a constant nickel concentration in the electrolyte. One known method is the re-dissolution of nickel carbonate (NiCOa). This approach has been used in the past in ZnNi Gravitel systems from ANDRITZ. There are also fully developed concepts available for the fully automated re-dosing of nickel carbonate.
[0004] To prevent any potentially released toxic NiCOa dust from escaping into the hall, the dissolution station must be quite complex and operated under negative pressure. Furthermore, NiCOa is only available on the market at relatively high prices, and there are also shortages of NiCOa, especially in the Chinese market. The novel approach of this invention is based on the re-dissolution of metallic nickel / nickel pellets in a nickel dissolution station. In this station, the electrolyte, which becomes depleted of nickel during deposition, is continuously re-enriched with nickel. The concept is similar to electrolytic zinc plating lines; however, nickel does not dissolve as readily in the electrolyte as zinc. Therefore, the process must be modified to increase the solubility of nickel.
[0005] The object of the invention is to develop a dissolution station for nickel which has the highest possible dissolution rate for metallic nickel, for example in the form of granules or pellets.
[0006] The inventor recognized that the solubility of nickel in the electrolyte increases in the presence of an oxidizing agent, especially in the presence of air or oxygen.
[0007] According to the invention, an oxidizing agent is added to the electrolyte, so that the metallic nickel dissolves better in the electrolyte.
[0008] According to the invention, it is also conceivable that the oxidizing agent is formed directly in the electrolyte, thereby increasing the solubility rate of nickel in the electrolyte.
[0009] According to the inventive method of claim 1, the electrolyte is supplied to a container containing metallic nickel, for example in the form of nickel pellets or nickel granules. An oxidizing agent, for example oxygen or air, is supplied to this electrolyte, or the oxidizing agent can also be formed in the electrolyte by an electrochemical reaction instead of or in addition to the addition. The presence of the oxidizing agent in the electrolyte increases the solubility of nickel in the electrolyte.
[0010] For nickel plating, nickel sulfamate and sulfonic acid, and optionally boric acid, can be used as the electrolyte. Sulfamic acid is preferably added to the nickel sulfamate electrolyte before the nickel is dissolved. It is advantageous if the pH of the electrolyte is adjusted to 1.6 to 2.2, preferably to 1.8 to 2, ideally to 1.9, by adding the sulfonic acid.
[0011] Nickel methanesulfonate and methanesulfonic acid (MSA), and optionally boric acid, can also be used as electrolytes for nickel plating. Similarly, nickel sulfate, sulfuric acid, and optionally boric acid could be used.
[0012] It is advantageous if the electrolyte is supplied to the container with the metallic nickel at a temperature of 40°C to 70°C, preferably at a temperature of 50°C to 60°C.
[0013] Oxygen or air can be injected into the electrolytes in the form of small bubbles.
[0014] It is also conceivable that the oxygen, preferably nascent oxygen, is formed directly in the electrolyte by electrolysis. For example, the oxygen can be formed in an electrolysis cell comprising an anode and a cathode. The electrolyte is supplied to the electrolysis cell as anolyte on the anode side, with oxygen being formed at the anode. The anode and cathode of the electrolysis cell are preferably separated from each other by a membrane, for example, a polymer electrolyte membrane. The electrolyte removed from the electrolysis cell, along with the oxygen formed within it, is then fed to the container with the metallic nickel.
[0015] It is also conceivable that the oxygen in the electrolyte is formed by the electrochemical reaction in the coating system and that the electrolyte, with the oxygen formed in it, is then supplied to the container with the metallic nickel.
[0016] In a preferred embodiment, the container for the metallic nickel is formed by a plastic basket, preferably a polypropylene basket. The basket could also be made of polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF). The basket could also be a metal basket coated with plastic.
[0017] This basket is surrounded by a larger container, the basket and the larger container being separated by a membrane (e.g., a polymer electrolyte membrane). An electrical potential is applied to the metallic nickel in the basket and to the larger container, so that the metallic nickel forms the anode and the larger container the cathode. This allows the metallic nickel to dissolve particularly well due to the oxygen present in the electrolyte and the applied potential. The invention also relates to a device for dissolving metallic nickel in an electrolyte. The device according to the invention has a container for the metallic nickel, wherein an electrolyte and an oxidizing agent in the form of oxygen or air can be supplied to the container.
[0018] Preferably, the device includes a basket, for example a plastic basket, for the metallic nickel. An electrical potential is applied to the nickel contained within, so that it forms the anode. For this purpose, the nickel in the basket is contacted via a conductor. If the basket is electrically conductive, the electrical potential can also be applied via the basket. The basket is surrounded by a cathode, with a membrane (e.g., a polymer electrolyte membrane) arranged between the basket and the cathode. The electrolyte is supplied to the electrolytic cell on the anode side. The electrical potential applied to the anode and cathode increases the solubility of the nickel in the basket.
[0019] The invention is described below with reference to drawings.
[0020] Fig. 1 shows an embodiment of a dissolving station for metallic nickel;
[0021] Fig. 2 shows an electrolysis cell for the formation of the oxidizing agent in the electrolyte; Fig. 3 shows a further embodiment of a dissolving station for metallic nickel;
[0022] Figure 1 shows an embodiment of a dissolving station for metallic nickel 1. The electrolyte 2 is fed from a circulation tank 23 of a coating system (nickel plating system) to the container 3, which contains the metallic nickel 1 in the form of nickel pellets, via a pump 11. A perforated plate 22 is arranged in the lower part of the container 3 to ensure the uniform distribution of the electrolyte 2.
[0023] In the present example, the electrolyte 2 consists of nickel sulfamate and sulfonic acid. The pH value of the electrolyte 2, which is supplied to the circulation tank 23, is measured by a pH meter 14. The pH meter is connected to the pump 12 via a measuring line 15. Amidosulfonic acid 16 is added to the electrolyte 2 from a container 13 by means of a corresponding control system using the pump 12, thus adjusting the pH value. It is advantageous if the pH value is between 1.6 and 2.2, preferably between 1.8 and 2, and ideally at 1.9.
[0024] An oxidizing agent 4 is added to the electrolyte 2 upstream of the container 3. In this case, the oxidizing agent 4 is oxygen or air. This oxygen addition increases the solubility of the nickel 1 in the electrolyte 2. Thus, the dissolution of the nickel 1 in the container 3 is intensified by the introduction of oxygen or air (if sufficiently reactive). Preferably, the oxygen or air is added to the electrolyte 2 in the form of small bubbles; the formation of a fluidized bed is also advantageous. The dissolution of nickel 1 proceeds according to the following reaction equation:
[0025] Ni + 2R-SO3H + ü O2Ni (R-SO3)2+ H2O
[0026] In the specific example using nickel sulfamate and sulfonic acid, the reaction equation is then:
[0027] Ni + 2H2NSO3H + ü O2Ni (SO3NH2)2+ H2O
[0028] The nickel-enriched electrolyte 2 leaves container 3 via an overflow 21 and is then returned to the circulation tank 23. From the circulation tank 23, the nickel-enriched electrolyte 2 is then fed to the coating system via line 24, and the nickel-depleted electrolyte 2 is returned to the circulation tank 23 via line 25. Nickel pellets can be added to container 3 via the downpipe 17.
[0029] Nickel methanesulfonate and methanesulfonic acid (MSA), or nickel sulfate and sulfuric acid, can also be used as electrolytes for nickel plating.
[0030] Boric acid can also be added to electrolyte 2, which serves as a pH buffer substance in nickel deposition.
[0031] The oxidizing agent 4 can either be added to the electrolyte 2 or it can be formed within the electrolyte 2. This is shown schematically in Figure 2.
[0032] The oxidizing agent 4 (oxygen) is generated in an electrolysis cell 5. The electrolysis cell 5 has an anode 6 and a cathode 7, with the electrolyte 2 being supplied as the anolyte on the anode side, so that oxygen (nascent oxygen) is generated at the anode 6. The anode 6 is made of titanium, for example. It is advantageous if the anode 6 is an MMO electrode. Mixed-metal oxide (MMO) electrodes, also called dimensionally stable anodes (DSA), are electrodes with high conductivity and corrosion resistance that are used as anodes in electrolysis. They are produced by coating a substrate, such as a pure titanium plate or an expanded titanium mesh, with a metal oxide. Suitable metal oxides include RuO₂, IrO₂, or PtO₂; these metal oxides possess good conductivity and catalyze the desired reaction.
[0033] The anode 6 and the cathode 7 are separated from each other by a polymer electrolyte membrane 8, for example by a Naf ion membrane, thereby inhibiting nickel transfer to the cathode 7.
[0034] On the cathode side, a catholyte 18, preferably the acid of electrolyte 2 (e.g., sulfamic acid, methanesulfonic acid, or sulfuric acid), is circulated. The oxygen-enriched electrolyte 2 can then be supplied to the container 3 containing the metallic nickel 1.
[0035] Figure 3 shows another possible embodiment of the invention. Here, the container 3 for the metallic nickel 1 is designed as a basket 9, preferably a plastic basket. The metallic nickel 1, for example in the form of nickel pellets, forms the anode 6 of an electrolysis cell 5. A larger container 10 surrounds the basket 9 and forms the cathode 7. A polymer electrolyte membrane 8 is arranged between the cathode 7 and the anode 6.
[0036] The electrolyte 2 is fed into the interior of the basket 9 on the anode side and dissolves the nickel pellets there. The electrical potential applied to the nickel pellets promotes the solubility of the nickel 1 in the electrolyte 2.
[0037] On the cathode side, a catholyte 18, for example the acid of electrolyte 2, is circulated. The basket 9, surrounded by the polymer electrolyte membrane 8, is taller than the larger container 10 and separated from it by a horizontal partition 19. This prevents the overflow 20 of the catholyte 18 from mixing with the overflow 21 of the nickel-enriched electrolyte 2 (anolyte). The nickel-enriched electrolyte 2 is returned to the circulation tank 23.
[0038] In another embodiment, it is also possible that the oxidizing agent 4 (e.g. oxygen) is formed directly in the deposition cells of the nickel plating system.
[0039] Reference sign
[0040] 1 Metallic nickel (nickel pellets, nickel granules) 2 Electrolyte
[0041] 3 containers
[0042] 4 Oxidizing agents
[0043] 5 Electrolysis cell
[0044] 6 Anode
[0045] 7 Cathode
[0046] 8 membrane (e.g. polymer electrolyte membrane)
[0047] 9 basket
[0048] 10 larger containers
[0049] 11 Pump for the electrolyte pump
[0050] Container for amidosulfonic acid
[0051] pH meter
[0052] Measuring lead
[0053] Sulfamic acid
[0054] Addition line for the metallic nickel (downpipe) catholyte
[0055] Horizontal partition
[0056] Overflow Catholyte 18
[0057] Electrolyte overflow 2
[0058] sieve sheet
[0059] Circulation tank
[0060] Line to the coating plant
[0061] Line from the coating plant
Claims
Patent claims 1. A method for dissolving metallic nickel (1), in particular metallic nickel pellets or nickel granules (1), in electrolytes (2) used for the electrolytic coating of metal substrates with nickel in a coating plant, characterized in that the electrolyte (2) is supplied to a container (3) in which metallic nickel (1) is located and wherein an oxidizing agent (4) is supplied to the electrolyte (2) and / or wherein an oxidizing agent (4) is formed in the electrolyte (2) by an electrochemical reaction, thereby increasing the solubility of nickel (1) in the electrolyte (2).
2. Method according to claim 1, characterized in that oxygen is used as the oxidizing agent (4).
3. Method according to claim 1 or 2, characterized in that nickel sulfamate and amidosulfonic acid and optionally boric acid are used as the electrolyte (2 ) for nickel plating.
4. Method according to claim 3, characterized in that amidosulfonic acid is added to the electrolyte (2 ) before dissolving nickel.
5. The method of claim 4, characterized in that the pH value in the electrolyte (2) is adjusted to 1.6 to 2.2, preferably to 1.8 to 2, ideally to 1.9, by adding the amidosulfonic acid.
6. The method of claim 1 or 2, characterized in that nickel methanesulfonate and methanesulfonic acid (MSA) and optionally boric acid are used as the electrolyte (2) for nickel plating.
7. Method according to claim 1 or 2, characterized in that nickel sulfate and sulfuric acid and optionally boric acid are used as the electrolyte (2 ) for nickel plating.
8. Method according to one of claims 1 or 7, characterized in that the electrolyte (2 ) is supplied to the container (3) at a temperature of 40°C to 70°C, preferably at a temperature of 50°C to 60°C .
9. Method according to one of claims 2 to 8, characterized in that the oxygen is injected into the electrolyte (2) in the form of small bubbles.
10. Method according to any one of claims 2 to 8, characterized in that the oxygen, preferably nascent oxygen, is formed by electrolysis in the electrolyte (2 ).
11. Method according to claim 10, characterized in that the oxygen is formed in an electrolysis cell (5) which has an anode (6) and a cathode (7), wherein the electrolyte (2) is supplied as anolyte on the anode side and oxygen is formed at the anode (6) and wherein the anode (6) and the cathode (7) are separated from each other by a membrane (8), in particular a polymer electrolyte membrane, and wherein the electrolyte (2) with the oxygen formed therein is supplied to the container (3) with the metallic nickel (1).
12. Method according to claim 10, characterized in that the oxygen in the electrolyte ( 2 ) is formed by the electrochemical reaction in the coating system and that the electrolyte ( 2 ) with the oxygen formed therein is supplied to the container ( 3 ) with the metallic nickel ( 1 ).
13. Method according to any one of claims 1 to 12, characterized in that the container (3) is formed by a basket (9), preferably a plastic basket, in which the metallic nickel (1) is located, wherein the basket (9) is surrounded by a larger container (10) and the basket (9) and the larger container (10) are separated from each other by a membrane (8), in particular a polymer electrolyte membrane, and wherein an electrical potential is applied to the metallic nickel (1) and to the larger container (10), such that the metallic nickel (1) forms the anode (6) and the larger container (10) forms the cathode (7), so that the metallic nickel (1) dissolves more easily due to the applied potential.
14. Device for dissolving metallic nickel (1) in an electrolyte (2), characterized in that the device has a container (3) for the metallic nickel (1), wherein an electrolyte (2) and an oxidizing agent (4) in the form of oxygen or air can be supplied to the container (3). 15.Device for dissolving metallic nickel (1) in an electrolyte (2), characterized in that the device has a basket (9), preferably a plastic basket, for the metallic nickel (1), wherein the metallic nickel (1) located in the basket (9) forms an anode (6) which is surrounded by a cathode (7) and wherein a membrane (8), in particular a polymer electrolyte membrane, is arranged between the basket (9) and the cathode (7), wherein an electrical potential is applied to the anode (6) and the cathode (7) and an electrolyte (2) with oxygen dissolved therein can be supplied to the basket (9) on the anode side.