CA1186275A - Process for regeneration of electrolyte containing tin salts by reducing the same - Google Patents
Process for regeneration of electrolyte containing tin salts by reducing the sameInfo
- Publication number
- CA1186275A CA1186275A CA000355062A CA355062A CA1186275A CA 1186275 A CA1186275 A CA 1186275A CA 000355062 A CA000355062 A CA 000355062A CA 355062 A CA355062 A CA 355062A CA 1186275 A CA1186275 A CA 1186275A
- Authority
- CA
- Canada
- Prior art keywords
- electrolyte
- ions
- grams
- liter
- tin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the regeneration of an electrolyte by reducing stannic ions in the electrolyte into stannous ions. This reduction is carried out by adding metallic tin to the electro-lyte containing tin salts and which is controlled so as to be acidic, and heating the resulting electrolyte. This process can be effectively used in regeneration of the electrolyte containing tin salts which is employed in colouring aluminum and electro-plating.
A process for the regeneration of an electrolyte by reducing stannic ions in the electrolyte into stannous ions. This reduction is carried out by adding metallic tin to the electro-lyte containing tin salts and which is controlled so as to be acidic, and heating the resulting electrolyte. This process can be effectively used in regeneration of the electrolyte containing tin salts which is employed in colouring aluminum and electro-plating.
Description
t~
1 This invention reld~es to a yrocess for th~ ~eductiorl re~eneratioll oE an electroplat:incj bath or a colourin~ electrolytc for aluminum and more particularly to a process for the regener-ation of an electrolyte by reducing stannic ions in the electro-lyte into stannous ions through the addi~ion of me-tallic tin to the used or old elec-trolyte.
A tin salt aqueous solution containing stannous ions (Sn2+) is generally used as an electrolyte containing tin ions.
However, an aqueous solution containing stannous ions is generally 1~ very unstable since stannous ions are easily oxidized into stannic ions ~Sn ) by oxygen in the air or oxygen generated during electrolysis. ~s stannic ions form in the electrolyte, the con-centration of stannous ions in the electrolyte decreases and the current efficiency of electrolysis is accordingly reduced.
Furthermore, the stannic ions become insoluble substances such as stannic acid, etc. which are likely to become colloids. ~reat difficulty is encountered in removing these insoluble substances by filteration and these become attached to the surEace of the pro duct and cause pitting. Therefore, in order to obtain good quality products, it is essential to control the concentration of stannic ions in the electrolyte.
In order to prevent the formation of insoluble precip-itates in the electrolyte it is possible to add a chelating agent to the electrolyte. However, under these circumstances, Sn4+ tends to accumulate in the electrolyte there~y leading to an increase in the concentration of Sn4 . As a result, electrolytic colouring or electroplating tend to become difficult. Therefore, a tin salt aqueous solution in which the concentration of stannic ions is increased by oxidation has been a~andoned.
Regeneration of the electrolyte by electrolytic reduc-tion has been described. One such regeneration method is described 1 in Japanese Pa~ellt Pu~Licat:ion No. 19~56~197~ to l'ujisash Industries, Ltd., published June 23, 197~. In accordance ~ith this electrolytic reduction method, the stannous ions are first reduced to metallic tin and thereafter the stannic ions are re-duced into metallic tln. Therefore, although this method is excellent, a relatively long processing ti~e is required, and equipment and operation costs are increased.
Also, a method of reducing stannic ions into stannous ions by adding metals which are more basic than tin has been carried out. According to this method, however, the added metal is present in the elctrolyte as a metal ion and it may have detrimental effects on electrolytic processing. It is, therefore, necessary to remove such metal ions. But the removal operation of the metal ions is very complicated. Thus, this method is neither practical nor economical.
The inventors have developed a method which permits the reduction of stannic ions by a simplified procedure in a short time and results in the formation of a regenerated electrolyte having a stable composition. Accordingly, the invention resides in adding tin meta:L in a form having a lar~e surface area to the electrolyte wh:ich is controlled such that it is acidic and heating the result:ing mixture thus causing the metallic tin and stannic ions to react with each other in an oxidation-reduction reaction to form stannous ions.
This invention provides a process for the regeneration of an electrolyte containing tin salts by reduction thereof.
The process is characterized in that metallic tin is added to the electrolyte while the pH of the electrolyte is controlled such that the electrolyte is acidic. If the pH is acidic, it is maintained at the existing level or it can be adjusted to .
7~
1 and maintained at a more prerera~le ac:idic level. Irhe electrolyte .i ~ thell heated .
In accordance wi-th the process of this invention, the stannic ions in the electrolyte are regenerated to stannous ions. After the reaction is completed, the unreacted metallic tin is taken out of the elec-trolyte and, as necessary, additional processes such as adjustment in the concentrations of other com-ponents in the electrolyte, adjustment in pH, etc. is carried out.
~he regenerated electrolyte can be re~used.
In accordance with this inven-tion, the process can be continuously carried out and the electrolyte can be used repeated-ly by recycling. Thus, the processing time can be greatly short-ened. For example, in the method as described in Japanese Patent Publication No. 19856/1978, the time required for the reduction of the stannic ions is 6 hours or more; whereas, in the process of this inven-tion, the required time is 1 hour or less and usually about 30 minutes is sufficient. Also, equipment and operation costs can be reduced and the quality of the product obtained can be controlled.
The electrolyte for use in this invention is subject t~
no special limitations so long as it contains tin salts. In a fresh electrolyte, almost all of the tin ions are stannous ions and t~ere are almost no stannic ions. As the electrolysis pro-ceeds, the concentration of stannic ions increases whereas the concentration of stannous ions relatively decreases.
The process of this invention is applied to an electro-lyte in which the concentration of stannic ions has increased to a certain extent, for example, where the ratio of Sn4~Sn2+ has reached 1/2 or more. In general, the electrolyte contains a chelating agent in order to keep the stannous and stannic ions in the state where they remain dissolved.
1 The process oE this invention will be explained in greater detall: firstly, the pll of ~he electrolyte is controlled such that the electrolyte is acidic. Control of the pH of the electrol~te is generally carried o~t by usiny acids. Those acids releasing the same anions as those existing in the electrolyte, such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, pyrophosphoric acid or various organic acids can be used singly or in admixtures comprising two or more thereof. Sulfuric acid is most preferred.
The pH of the electrolyte is usually controlled at about 4orlessand preferably in the range of from about 0.5 to about 2. ~here the pH is too low, the reduction rate of stannic ions is somewhat reduced although me-tallic tin is promptly dis~
solved. On the other hand, where the pH exceeds ~, metallic tin is less dissolved and the reduction does not proceed promptly.
When the pH o~ the electrolyte has reached the desired range, metallic tin is added to the electrolyte and the resulting electrolyte is hea-ted. It is preferred to add metallic tin having high activity for reducing s-tannic ions into stannous ions. For example, metallic tin in a form having a large specific surface area such as fine powder, thin foils, spongesl etc. is preferably used.
Metallic tin having such a high specific surface area can be produced as follows: an acidic solution (e.g., an electro-plating solution or a colouring electrolyte for aluminium) con-taining stannous ions and/or stannic ions is used as an electro-lyte and a direct current is passed through the electrolyte with electrically conductive materials such as metal or carbon as anode and cathode whereby tin ions (Sn2+, Sn4+) are deposited as metal-lic tin on the cathode. ~he thus-obtained metallic tin is in a spongy form, has a high specific surface area and can be easily separated ~rom the cathode.
1 There is no special limit to the amounl of metall:ic tln which may be added to the elec~rolyte. A su:itable arnount, however, can be de-termlned depending upon the concentration of stannic ions in the electroly~e, the concentration of stannous ions, etc. In general, it should be about l to lO times the number of moles required to reduce entirely the stannic ions in the elec-trolyte. Even if the metallic tin is added in excess, the unreacted metallic tin precipitates to the bottom of the re-actor and can be easily separated out. Therefore, excess metallic tin has no adverse effect on the electrolyte. The sep~
arated metallic tin can be re-used.
The addition of metallic tin causes the metallic tin and stannic ions to react with each other according to the following oxidation-reduction reaction:
Sn ~ Sn~ - > 2Sn2~
~ ecause the reaction is accelerated by heating, from the standpoint of rate of reaction it is preferred to heat the electro-lyte. However, when the electrolyte is liable to deteriorate in quality at high temperatures, the process should be conducted at lower temperatures. In these circumstances, the heating temper-ature is generally set in the range of from about 8~C to about the boiling temperature of the electrolyte.
With regard to the heating time, the electrolyte need be heated only for as long as is required to c~use the reduction reaction to proceed as far as desired. Because the heating time depends upon the shape and amount of the metallic tin which has been added and other various conditions, it cannot be determined unconditionally. ~owever, a heating time of l hour or less is usually sufficient since the reduction reaction of stannic ions is almost completed within l hour as shown in Examples described hereinafter.
'7~
1 The Eollow:in~ exampl~s ar~ c3iven to illustrate th:is il~vention in greater detail. In these examples, the concentration of stannic sulfate is shown as a concen-tration converted to SnSO~.
EX~MPLE 1 (1) Production of Metallic Tin A direct current was passed through an old or used colouring electrolyte for aluminium consisting of 9.0 grams/liter of stannous sulfate, 11.1 grams/liter of stannic sulfate, 70 grams/liter of citric acid and 20 grams/liter of sulfuric acid and having a pH of 1.5 with tin and stainless steel as anode and - cathode respectively to deposit sponge-like metallic tin on the cathode.
1 This invention reld~es to a yrocess for th~ ~eductiorl re~eneratioll oE an electroplat:incj bath or a colourin~ electrolytc for aluminum and more particularly to a process for the regener-ation of an electrolyte by reducing stannic ions in the electro-lyte into stannous ions through the addi~ion of me-tallic tin to the used or old elec-trolyte.
A tin salt aqueous solution containing stannous ions (Sn2+) is generally used as an electrolyte containing tin ions.
However, an aqueous solution containing stannous ions is generally 1~ very unstable since stannous ions are easily oxidized into stannic ions ~Sn ) by oxygen in the air or oxygen generated during electrolysis. ~s stannic ions form in the electrolyte, the con-centration of stannous ions in the electrolyte decreases and the current efficiency of electrolysis is accordingly reduced.
Furthermore, the stannic ions become insoluble substances such as stannic acid, etc. which are likely to become colloids. ~reat difficulty is encountered in removing these insoluble substances by filteration and these become attached to the surEace of the pro duct and cause pitting. Therefore, in order to obtain good quality products, it is essential to control the concentration of stannic ions in the electrolyte.
In order to prevent the formation of insoluble precip-itates in the electrolyte it is possible to add a chelating agent to the electrolyte. However, under these circumstances, Sn4+ tends to accumulate in the electrolyte there~y leading to an increase in the concentration of Sn4 . As a result, electrolytic colouring or electroplating tend to become difficult. Therefore, a tin salt aqueous solution in which the concentration of stannic ions is increased by oxidation has been a~andoned.
Regeneration of the electrolyte by electrolytic reduc-tion has been described. One such regeneration method is described 1 in Japanese Pa~ellt Pu~Licat:ion No. 19~56~197~ to l'ujisash Industries, Ltd., published June 23, 197~. In accordance ~ith this electrolytic reduction method, the stannous ions are first reduced to metallic tin and thereafter the stannic ions are re-duced into metallic tln. Therefore, although this method is excellent, a relatively long processing ti~e is required, and equipment and operation costs are increased.
Also, a method of reducing stannic ions into stannous ions by adding metals which are more basic than tin has been carried out. According to this method, however, the added metal is present in the elctrolyte as a metal ion and it may have detrimental effects on electrolytic processing. It is, therefore, necessary to remove such metal ions. But the removal operation of the metal ions is very complicated. Thus, this method is neither practical nor economical.
The inventors have developed a method which permits the reduction of stannic ions by a simplified procedure in a short time and results in the formation of a regenerated electrolyte having a stable composition. Accordingly, the invention resides in adding tin meta:L in a form having a lar~e surface area to the electrolyte wh:ich is controlled such that it is acidic and heating the result:ing mixture thus causing the metallic tin and stannic ions to react with each other in an oxidation-reduction reaction to form stannous ions.
This invention provides a process for the regeneration of an electrolyte containing tin salts by reduction thereof.
The process is characterized in that metallic tin is added to the electrolyte while the pH of the electrolyte is controlled such that the electrolyte is acidic. If the pH is acidic, it is maintained at the existing level or it can be adjusted to .
7~
1 and maintained at a more prerera~le ac:idic level. Irhe electrolyte .i ~ thell heated .
In accordance wi-th the process of this invention, the stannic ions in the electrolyte are regenerated to stannous ions. After the reaction is completed, the unreacted metallic tin is taken out of the elec-trolyte and, as necessary, additional processes such as adjustment in the concentrations of other com-ponents in the electrolyte, adjustment in pH, etc. is carried out.
~he regenerated electrolyte can be re~used.
In accordance with this inven-tion, the process can be continuously carried out and the electrolyte can be used repeated-ly by recycling. Thus, the processing time can be greatly short-ened. For example, in the method as described in Japanese Patent Publication No. 19856/1978, the time required for the reduction of the stannic ions is 6 hours or more; whereas, in the process of this inven-tion, the required time is 1 hour or less and usually about 30 minutes is sufficient. Also, equipment and operation costs can be reduced and the quality of the product obtained can be controlled.
The electrolyte for use in this invention is subject t~
no special limitations so long as it contains tin salts. In a fresh electrolyte, almost all of the tin ions are stannous ions and t~ere are almost no stannic ions. As the electrolysis pro-ceeds, the concentration of stannic ions increases whereas the concentration of stannous ions relatively decreases.
The process of this invention is applied to an electro-lyte in which the concentration of stannic ions has increased to a certain extent, for example, where the ratio of Sn4~Sn2+ has reached 1/2 or more. In general, the electrolyte contains a chelating agent in order to keep the stannous and stannic ions in the state where they remain dissolved.
1 The process oE this invention will be explained in greater detall: firstly, the pll of ~he electrolyte is controlled such that the electrolyte is acidic. Control of the pH of the electrol~te is generally carried o~t by usiny acids. Those acids releasing the same anions as those existing in the electrolyte, such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, pyrophosphoric acid or various organic acids can be used singly or in admixtures comprising two or more thereof. Sulfuric acid is most preferred.
The pH of the electrolyte is usually controlled at about 4orlessand preferably in the range of from about 0.5 to about 2. ~here the pH is too low, the reduction rate of stannic ions is somewhat reduced although me-tallic tin is promptly dis~
solved. On the other hand, where the pH exceeds ~, metallic tin is less dissolved and the reduction does not proceed promptly.
When the pH o~ the electrolyte has reached the desired range, metallic tin is added to the electrolyte and the resulting electrolyte is hea-ted. It is preferred to add metallic tin having high activity for reducing s-tannic ions into stannous ions. For example, metallic tin in a form having a large specific surface area such as fine powder, thin foils, spongesl etc. is preferably used.
Metallic tin having such a high specific surface area can be produced as follows: an acidic solution (e.g., an electro-plating solution or a colouring electrolyte for aluminium) con-taining stannous ions and/or stannic ions is used as an electro-lyte and a direct current is passed through the electrolyte with electrically conductive materials such as metal or carbon as anode and cathode whereby tin ions (Sn2+, Sn4+) are deposited as metal-lic tin on the cathode. ~he thus-obtained metallic tin is in a spongy form, has a high specific surface area and can be easily separated ~rom the cathode.
1 There is no special limit to the amounl of metall:ic tln which may be added to the elec~rolyte. A su:itable arnount, however, can be de-termlned depending upon the concentration of stannic ions in the electroly~e, the concentration of stannous ions, etc. In general, it should be about l to lO times the number of moles required to reduce entirely the stannic ions in the elec-trolyte. Even if the metallic tin is added in excess, the unreacted metallic tin precipitates to the bottom of the re-actor and can be easily separated out. Therefore, excess metallic tin has no adverse effect on the electrolyte. The sep~
arated metallic tin can be re-used.
The addition of metallic tin causes the metallic tin and stannic ions to react with each other according to the following oxidation-reduction reaction:
Sn ~ Sn~ - > 2Sn2~
~ ecause the reaction is accelerated by heating, from the standpoint of rate of reaction it is preferred to heat the electro-lyte. However, when the electrolyte is liable to deteriorate in quality at high temperatures, the process should be conducted at lower temperatures. In these circumstances, the heating temper-ature is generally set in the range of from about 8~C to about the boiling temperature of the electrolyte.
With regard to the heating time, the electrolyte need be heated only for as long as is required to c~use the reduction reaction to proceed as far as desired. Because the heating time depends upon the shape and amount of the metallic tin which has been added and other various conditions, it cannot be determined unconditionally. ~owever, a heating time of l hour or less is usually sufficient since the reduction reaction of stannic ions is almost completed within l hour as shown in Examples described hereinafter.
'7~
1 The Eollow:in~ exampl~s ar~ c3iven to illustrate th:is il~vention in greater detail. In these examples, the concentration of stannic sulfate is shown as a concen-tration converted to SnSO~.
EX~MPLE 1 (1) Production of Metallic Tin A direct current was passed through an old or used colouring electrolyte for aluminium consisting of 9.0 grams/liter of stannous sulfate, 11.1 grams/liter of stannic sulfate, 70 grams/liter of citric acid and 20 grams/liter of sulfuric acid and having a pH of 1.5 with tin and stainless steel as anode and - cathode respectively to deposit sponge-like metallic tin on the cathode.
(2) Regeneration by reducing To a used colouring electrolyte for aluminum consisting of 4.0 grams/liter of stannous sulfate, 15.1 grams/
liter of stannic sulfate, 30 grams/liter of tartaric acid, 30 grams/liter of nic:kel sulfate and 20 grams/liter of ammonium sul-fate and having a pH of 7.5 was added 40 grams/liter of sulfuric acid -to adjust the pH to 0.9. Thereafter, 18 grams/liter of the sponge-like metallic tin as obtained in ~1) was added to the above electrolyte and the resulting mixture was heated for 20 minutes at 100C. After heating, the obtained electrolyte contained 21.2 grams/liter of stannous sulfate and 0.7 grams/liter of stannic sulfate.
To a used neutral tin electroplating solution consisting of 41 grams/liter of stannous sulfate, 89 grams/liter of stannic sulfate, lS0 grams/liter of ammonium citrate and 100 grams/liter of ammonium sulfate and having a pH of 6.5 was added
liter of stannic sulfate, 30 grams/liter of tartaric acid, 30 grams/liter of nic:kel sulfate and 20 grams/liter of ammonium sul-fate and having a pH of 7.5 was added 40 grams/liter of sulfuric acid -to adjust the pH to 0.9. Thereafter, 18 grams/liter of the sponge-like metallic tin as obtained in ~1) was added to the above electrolyte and the resulting mixture was heated for 20 minutes at 100C. After heating, the obtained electrolyte contained 21.2 grams/liter of stannous sulfate and 0.7 grams/liter of stannic sulfate.
To a used neutral tin electroplating solution consisting of 41 grams/liter of stannous sulfate, 89 grams/liter of stannic sulfate, lS0 grams/liter of ammonium citrate and 100 grams/liter of ammonium sulfate and having a pH of 6.5 was added
3~ 60 grams/liter of sulfuric acid to adjust the pH to 0.7. There-after, 148 grams/liter of the sponge-like metallic tin as obtained 1 in Exam~)le l was added to the plating solution and the resulting mixture was heated at 96C for 40 minutes. After heating, the obtained plating solution contained 222 grams/li-ter of stannous su]fate and 8 grams/liter of stannic sulfate.
EX~MPLE 3 To a used lustrous-tin-cobalt electroplatiny solution consisting of 10 grams/liter of stannous sulfate, 10 grams/liter of stannic sulfate, 50 grams/liter of cobalt sulfa-te and 200 grams/liter of sodium pyrophosphate was added 60 grams/
lQ liter of sulfuric acid. Thereafter, 10.7 grams/liter of the sponge-like metallic tin as obtained in Example 1 was added to the plating solution and the resultiny mixture was heated at 100C
for 10 minutes. After heating, the obtained plating solution contained 21 grams/liter of stannous sulfate and 4 grams/liter of stannic sulfate.
To a used colouring electrolyte for aluminum consisting of 9.0 grams/liter of stannous sulfate, 11 grams/liter of stannic sulfate/ 70 grams/liter of citric acid and 20 grams/
liter of sulfuric acid and having a pH of 1.5 was added 21.4 grams/
liter of the sponge-like metallic tin as obtained in Example 1.
The resulting mixture was heated at 98C for 10 minutes. A-Eter heating, the obtained electrolyte contained 30 grams~liter of stannous sulfate and 4 grams/liter of stannic sulfate.
The procedure of Example 4 was repeated except that 100 mesh powdery tin reagent was used in place of the sponge-like metaLlic tin. After heating, the obtained electrolyte contained 11.5 grams/liter of stannous sulfate and 9 gramsJliter of stannic sulfate.
EX~MPLE 3 To a used lustrous-tin-cobalt electroplatiny solution consisting of 10 grams/liter of stannous sulfate, 10 grams/liter of stannic sulfate, 50 grams/liter of cobalt sulfa-te and 200 grams/liter of sodium pyrophosphate was added 60 grams/
lQ liter of sulfuric acid. Thereafter, 10.7 grams/liter of the sponge-like metallic tin as obtained in Example 1 was added to the plating solution and the resultiny mixture was heated at 100C
for 10 minutes. After heating, the obtained plating solution contained 21 grams/liter of stannous sulfate and 4 grams/liter of stannic sulfate.
To a used colouring electrolyte for aluminum consisting of 9.0 grams/liter of stannous sulfate, 11 grams/liter of stannic sulfate/ 70 grams/liter of citric acid and 20 grams/
liter of sulfuric acid and having a pH of 1.5 was added 21.4 grams/
liter of the sponge-like metallic tin as obtained in Example 1.
The resulting mixture was heated at 98C for 10 minutes. A-Eter heating, the obtained electrolyte contained 30 grams~liter of stannous sulfate and 4 grams/liter of stannic sulfate.
The procedure of Example 4 was repeated except that 100 mesh powdery tin reagent was used in place of the sponge-like metaLlic tin. After heating, the obtained electrolyte contained 11.5 grams/liter of stannous sulfate and 9 gramsJliter of stannic sulfate.
Claims (3)
1. In a process for regenerating an electrolyte containing tin salts by reducing stannic ions into stannous ions, the im-provement comprising adding metallic tin to the electrolyte which is controlled so as to be acidic and heating the resulting mixture.
2. The process as claimed in claim 1 wherein after adjust-ment of the pH of the electrolyte so as to be acidic, the metal-lic tin is added to the electrolyte.
3. The process as claimed in claim 1 or 2 wherein the metallic tin has a large specific surface area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000355062A CA1186275A (en) | 1980-06-27 | 1980-06-27 | Process for regeneration of electrolyte containing tin salts by reducing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000355062A CA1186275A (en) | 1980-06-27 | 1980-06-27 | Process for regeneration of electrolyte containing tin salts by reducing the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1186275A true CA1186275A (en) | 1985-04-30 |
Family
ID=4117298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000355062A Expired CA1186275A (en) | 1980-06-27 | 1980-06-27 | Process for regeneration of electrolyte containing tin salts by reducing the same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1186275A (en) |
-
1980
- 1980-06-27 CA CA000355062A patent/CA1186275A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1036534A (en) | Method and composition for producing bright palladium electrodepositions | |
| US5419821A (en) | Process and equipment for reforming and maintaining electroless metal baths | |
| CA1256819A (en) | Process for reconditioning a used ammoniacal copper etching solution containing copper solute | |
| RU2181150C2 (en) | Method of pickling steel | |
| JP4019723B2 (en) | Electrolytic phosphate chemical treatment method | |
| US4906340A (en) | Process for electroplating metals | |
| US4432844A (en) | Process for regeneration of electrolyte containing tin salts by reducing the same | |
| CA1186275A (en) | Process for regeneration of electrolyte containing tin salts by reducing the same | |
| USRE34191E (en) | Process for electroplating metals | |
| Kekesi | Electrorefining in aqueous chloride media for recovering tin from waste materials | |
| US5112447A (en) | Process for electroplating | |
| US4466865A (en) | Trivalent chromium electroplating process | |
| EP0054074B1 (en) | Process for reducing and reclaiming electrolyte containing tin salt | |
| US6569311B2 (en) | Continuous electrochemical process for preparation of zinc powder | |
| US5246563A (en) | Process for the electrolytic zinc coating of stainless steel | |
| JP2982658B2 (en) | Method of lowering metal concentration in electroplating solution | |
| US2131427A (en) | Process of electrolytically depositing iron and nickel alloy | |
| US6569310B2 (en) | Electrochemical process for preparation of zinc powder | |
| FR2685013B1 (en) | ||
| GB2027055A (en) | Manganese coating of steels | |
| Stanković | The Effect of Fe (II) ions on kinetics and mechanism of anodic dissolution and cathodic deposition of copper | |
| Bieliński et al. | Electrolytic Ni-Pb-P alloys | |
| US20030106806A1 (en) | Electrochemical process for preparation of zinc metal | |
| JPS604280B2 (en) | Reductive regeneration method of tin salt-containing electrolyte | |
| Johal et al. | Electrodeposition of thallium from a sulphamate solution |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |