Method for reducing content of sulfur-containing inorganic salt and / or sulfur-containing organic matter in electrolytic manganese

Abstract

The invention belongs to metal passivation, and particularly relates to a method for reducing the content of sulfur-containing inorganic salt and / or sulfur-containing organic matter in electrolytic manganese, electrolytic manganese is obtained through electrolysis, the electrolytic manganese is in contact with sulfur reduction liquid, the content of the sulfur-containing inorganic salt and / or the sulfur-containing organic matter in the electrolytic manganese is reduced, and sulfur reduction electrolytic manganese is obtained; the sulfur reduction liquid is alkali liquid with a dissolved quality improving agent and the pH value of more than or equal to 10; the upgrading agent comprises one or more of water-soluble organic amines, an organic carboxylic acid source, silicate, water-soluble zinc salt and a soluble aluminum source; the sulfur-containing inorganic salt comprises at least one of sulfate and sulfide salt. The process provided by the invention can effectively adapt to the sulfur-containing characteristic of electrolytic manganese, and can effectively remove sulfur in the electrolytic manganese.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of manganese metal preparation, in particular to the field of electrolytic manganese preparation. BACKGROUND

[0002] Manganese is a metal element widely used in industry, widely used in the steel industry, non-ferrous metallurgy, battery industry, electronics industry, agriculture and other fields. According to the national standard, the sulfur content of qualified electrolytic manganese product shall not exceed 0.05%. Under normal production conditions, it is completely possible to achieve. But in actual production, often because of the change of production conditions or improper operation, it is easy to cause the instability of the electrolytic cell liquid, and then cause the sulfur content in the product to exceed the standard. The residual sulfur in electrolytic manganese mainly includes inorganic salts containing sulfur (such as inorganic sulfate, sulfide salt, etc.), organic matter containing sulfur (sodium dimethyl dithiocarbamate, etc.), which is firmly combined on the surface of electrolytic manganese, and most of them are targeted in the metal lattice of electrolytic manganese, which is more difficult to remove, and it is difficult to remove by conventional cleaning, even with high-energy intensive cleaning, it is also difficult to obtain a deep removal effect, which is one of the pain points that electrolytic manganese production enterprises often face. Therefore, the research on the reduction technology of sulfur content in electrolytic manganese production and its control conditions is one of the keys to improve the quality of manganese products.

[0003] In view of the characteristics and removal difficulties of the sulfur components of the existing electrolytic manganese, the existing technology has no effective method, and the main means is to control the cleaning equipment and cleaning means. For example, the Chinese patent application with the authorization announcement number CN219965769U discloses a new ammonium sulfate removal device for electrolytic manganese wet smelting. For another example, the Chinese patent document with the publication number CN101767802A discloses a method for recovering ammonium sulfate from electrolytic manganese waste slag, which specifically records that a double decomposition reaction is carried out between ammonium sulfate and lime milk slurry to generate calcium sulfate and release ammonia gas to reduce ammonium sulfate. In addition, the Chinese patent with the publication number CN106929864A discloses a cleaning method for electrolytic manganese with manganese cathode plate, which specifically discloses a process of removing ammonium sulfate by boiling water. The Chinese patent document with the publication number CN114871240A discloses a desulfurization roasting process at a temperature of 900-1000℃. The Chinese patent document with the publication number CN103290228A further discloses a scheme for removing sulfur from metal manganese by using a desulfurization and decarburization agent for auxiliary roasting, wherein the desulfurization and decarburization agent comprises CaO:Al2O3:CaF2:Na3AlF6. The Chinese patent document with the publication number CN102701611A discloses a scheme for removing sulfate from electrolytic manganese slag by precipitation conversion method, which specifically discloses a scheme for removing ammonium sulfate by using ammonium bicarbonate.

[0004] In summary, although there are some metal manganese desulfurization processes in the prior art, most of them need to be assisted by special equipment, or a large amount of cleaning, or need to destroy the structure of the electrode plate, and it is also difficult to maintain the original form and process of electrolytic manganese, and to realize the high selectivity removal of sulfate, sulfide and sulfur-containing organic matter of electrolytic manganese electrode plate. SUMMARY

[0005] In view of the problems of desulfurization of electrolytic manganese, the present application provides a method for reducing the content of sulfur-containing inorganic salt and / or sulfur-containing organic matter in electrolytic manganese, which aims to effectively reduce the content of sulfur-containing components such as sulfate, sulfide and sulfur-containing organic matter in electrolytic manganese, and obtain high-quality electrolytic manganese with low sulfur content.

[0006] Elemental manganese has good sulfur affinity and the two are easily combined. The residual sulfur in the production of electrolytic manganese mainly includes inorganic sulfate, sulfide and sulfur-containing organic matter. Such components are firmly combined on the surface of electrolytic manganese during the electrolysis stage, and most of them are targeted to be complexed in the metal lattice of electrolytic manganese, which is more difficult to remove. It is difficult to remove through conventional cleaning, and even with high-energy intensive cleaning, it is also difficult to achieve a deep removal effect. In view of this problem, the present application provides the following scheme after in-depth research:

[0007] A method for reducing the content of sulfur-containing inorganic salt and / or sulfur-containing organic matter in electrolytic manganese, electrolytic manganese is obtained, and the electrolytic manganese is contacted with a sulfur-reducing liquid to reduce the sulfur-containing inorganic salt and / or sulfur-containing organic matter therein, thereby obtaining sulfur-reduced electrolytic manganese;

[0008] The sulfur-reducing liquid is an alkaline solution with pH≥10 containing a quality improver;

[0009] The quality improver includes one or more of water-soluble organic amine, organic carboxylic acid source, soluble aluminum source, silicate, and water-soluble zinc salt.

[0010] The sulfur-containing inorganic salt includes at least one of sulfate and sulfide.

[0011] In the present application, the sulfur-reducing liquid can be based on the joint synergy of its components, which can unexpectedly adapt to the physicochemical characteristics of electrolytic manganese, optimize its surface structure, and further promote the conversion and complexation of sulfur-containing organic matter and inorganic salt in electrolytic manganese, thereby effectively improving the content of sulfur-containing organic matter, sulfide and sulfate in electrolytic manganese. In addition, the present method does not need to rely on special high-energy equipment, and does not need excessive cleaning, with small three-waste output.

[0012] In the present application, the cathode of the electrolysis stage of electrolytic manganese is a solution containing ammonium sulfate and manganese sulfate. In addition, the cathode solution can also contain sodium dimethyl dithiocarbamate (sodium dimethyldithiocarbamate) and sulfide.

[0013] In this invention, the sulfate includes at least one selected from ammonium sulfate, manganese sulfate, and magnesium sulfate. The sulfide includes sodium sulfide, ammonium sulfide, potassium sulfide, and calcium sulfide, etc. The sulfur-containing organic compound includes sodium dimethyl dithiocarbamate.

[0014] In this invention, the quality improving agent contains organic amines, including alkanolamine compounds, and further includes at least one of ethanolamine, ethylenediamine, triethanolamine, and triisopropanolamine.

[0015] The soluble aluminum source includes at least one of aluminic acid, aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, and organoaluminum salts.

[0016] The silicate includes at least one of sodium silicate, potassium silicate, potassium aluminum silicate, sodium potassium aluminum silicate, and lithium silicate.

[0017] The zinc salts mentioned include at least one of zinc nitrate, zinc sulfate, zinc chloride, and sodium zincate.

[0018] The organic carboxylic acid source includes water-soluble C2-C18 units or polycarboxylic acid salts (sodium salts, ammonium salts, potassium salts, etc.), further comprising alcohol-containing dicarboxylic acid compounds, and even further comprising tartaric acid and its salts.

[0019] In this invention, the quality improver includes organic amines, soluble aluminum sources, and organic carboxylic acid sources; more preferably, it includes alcohol amine compounds, soluble aluminum sources, and alcohol-containing dicarboxylic acid compounds, and even more preferably, it includes triethanolamine, aluminates, and tartrates.

[0020] Preferably, in the quality improver, the weight ratio of organic amines, soluble aluminum source and organic carboxylic acid source is 1-4:1-2:1, more preferably 2-3:1-2:1.

[0021] In this invention, the concentration of the upgrading agent in the desulfurization solution is 0.1-350 g / L, more preferably 0.5-100 g / L, and more preferably 10-90 g / L.

[0022] In this invention, the alkaline component in the desulfurization solution includes at least one of sodium hydroxide, potassium hydroxide, and ammonia water.

[0023] In this invention, the pH of the desulfurization solution is 10-13.8, preferably 12-13.

[0024] In this invention, the electrolytic manganese obtained by electrolysis is subjected to plate formation, passivation, and aeration cleaning after being removed from the electrolysis tank;

[0025] The electrolytic manganese comes into contact with the desulfurizing solution before, during, and after at least one of the processing steps in the plate-forming, passivation, and aeration cleaning processes.

[0026] Preferably, after the electrolytic manganese is removed from the tank, it undergoes rinsing, plate formation, passivation, and aeration cleaning treatment, wherein any step in rinsing or plate formation is carried out in the desulfurization solution.

[0027] In this invention, the residence time of electrolytic manganese in the desulfurization solution is more than 5 seconds. Considering efficiency and effectiveness, it can be further extended to 10-300 seconds, and further extended to 20-60 seconds.

[0028] In this invention, the temperature of electrolytic manganese during the desulfurization treatment stage is 10–80°C, for example, it can be room temperature.

[0029] Beneficial effects

[0030] In this invention, the components of the desulfurization solution can be adapted to the physicochemical characteristics of electrolytic manganese. When it comes into contact with electrolytic manganese that requires desulfurization, it can gently and efficiently remove and / or transform sulfur-containing organic matter, sulfates, sulfides, sodium dimethyl dithiocarbamate and other sulfur-containing compounds. This can effectively improve the content of sulfur-containing organic matter, sulfates and other components in electrolytic manganese, improve the quality of electrolytic manganese and greatly enhance the product value. Detailed Implementation

[0031] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below in conjunction with the specification and embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0032] In this invention, as an understandable approach, the manganese metal surfaces tested below were all prepared using the following methods:

[0033] First, electrolytic manganese metal was prepared in a diaphragm tank using an electrolytic method: stainless steel was used as the cathode plate, and lead-silver alloy plate was used as the anode plate. Electrolysis conditions: the catholyte consisted of 100 g / L ammonium sulfate, 76.9 g / L manganese sulfate, and 0.05 g / L selenium dioxide; the catholyte pH was approximately 6.8–7.0; and the current density was 350 A / m³. 2 The electrolysis temperature is 38℃ and the electrolysis time is 24h. Electrolytic manganese to be desulfurized (total sulfur content is 0.108%) is obtained after the electrolytic manganese is discharged from the cell. After being discharged from the cell, the electrolytic manganese undergoes a series of operations such as rinsing (soaking), plate forming, passivation, aeration cleaning, and drying to finally obtain the finished electrolytic manganese product.

[0034] The sulfur content in electrolytic manganese products was determined using the method specified in GB / T 5686.7.

[0035] In the following cases, unless otherwise stated, the desulfurizing solution is an aqueous alkaline solution of the aforementioned components, and its pH is adjusted by sodium hydroxide.

[0036] In the aeration cleaning tank, a gas-liquid homogeneous system is used for cleaning, and water is the cleaning medium.

[0037] Example 1

[0038] Rinsing solution: contains 20 g / L of quality improver (ethanolamine), and the pH of the solution is adjusted to 10.5.

[0039] After electrolysis of manganese is completed and the manganese plate is removed from the tank, it is directly immersed in the rinsing solution prepared in this embodiment for 30 seconds. Then, it undergoes passivation (3 g / L potassium dichromate for 1 minute), aeration cleaning for 10 minutes, and drying at 90°C for 10 minutes to obtain the finished metallic manganese product. The product contains 0.011% sulfur and 0.008% carbon.

[0040] Example 2

[0041] Compared to Example 1, the only difference is that the composition of the eluent in the rinsing solution is changed, while the total concentration of the eluent and the pH of the rinsing solution remain the same as in Example 1. The experimental groups are as follows:

[0042] Group A: The quality improver is ethylenediamine.

[0043] Group B: The quality improver is triethanolamine.

[0044] Group C: The quality improving agent is potassium aluminate;

[0045] Group D: The quality improver is sodium tartrate.

[0046] Group E: The quality improvers are triethanolamine, potassium aluminate and sodium tartrate in a weight ratio of 10:5:5, and the aeration and washing time is shortened to 5 minutes.

[0047] Group F: The rinsing solution is an alkaline solution of 20 g / L triethanolamine, and the pH is controlled at 10.5; the aeration and rinsing time is shortened to 5 minutes.

[0048] The other processes and operations are the same as in Example 1, and the results are as follows:

[0049] The sulfur content in Group A products is 0.012%, and the carbon content is 0.009%.

[0050] The sulfur content in Group B products is 0.011%, and the carbon content is 0.009%.

[0051] The sulfur content in group C products is 0.013%, and the carbon content is 0.008%.

[0052] The sulfur content in group D products is 0.015%, and the carbon content is 0.010%.

[0053] The sulfur content in group E products is 0.008%, and the carbon content is 0.007%.

[0054] The F group of products contains 0.015% sulfur and 0.009% carbon.

[0055] As can be seen from Examples 1 and 2, the combination of triethanolamine, potassium aluminate and sodium tartrate of the present invention can achieve better sulfur removal effect while significantly shortening the aeration and washing time. This also shows that the combination of the components can unexpectedly achieve synergy and enhance the removal effect of organic and inorganic sulfur.

[0056] Example 3

[0057] Compared to Example 2, the only difference was the change in the pH of the rinsing solution. The experimental groups were as follows:

[0058] Group A: The pH of the rinsing solution in Example 2E was controlled at 12.5; and the subsequent aeration and rinsing was controlled at 3 minutes.

[0059] Group B: The pH of the rinsing solution in Example 2B was controlled at 13.0; and the aeration rinsing time was shortened to 5 minutes.

[0060] Group C: The pH of the rinsing solution in Example 2E was controlled at 12.0; the aeration rinsing time was shortened to 5 minutes.

[0061] The other processes and operations are the same as in Example 2, and the results are as follows:

[0062] The sulfur content in Group A products is 0.008%, and the carbon content is 0.007%.

[0063] The sulfur content in Group B products is 0.010%, and the carbon content is 0.009%.

[0064] The sulfur content and carbon content in Group C products are both 0.007%.

[0065] Example 4

[0066] Compared to Example 2, the only difference was the change in the concentration of the eluent in the rinsing solution. The experimental groups were as follows:

[0067] Group A: The rinsing solution is an alkaline solution of 50 g / L triethanolamine, with the pH controlled at 10.5; the aeration and rinsing time is 5 minutes.

[0068] Group B: The rinsing solution is an alkaline solution of 80 g / L triethanolamine, with the pH controlled at 10.5; the aeration and rinsing time is 5 minutes.

[0069] Group C: The rinsing solution consisted of 15 g / L triethanolamine, 8 g / L potassium aluminate, and 5 g / L sodium tartrate, with the pH controlled at 10.5; the aeration and rinsing time was shortened to 5 minutes.

[0070] The other processes and operations are the same as in Example 2, and the results are as follows:

[0071] The sulfur content in Group A products is 0.009%, and the carbon content is 0.008%.

[0072] The sulfur content in Group B products is 0.008%, and the carbon content is 0.007%.

[0073] The sulfur content in group C products is 0.007%, and the carbon content is 0.006%.

[0074] Example 5

[0075] Compared with Example 2, the only difference is that the process of contacting the desulfurizing solution with the electrolytic manganese plate is changed. The desulfurizing solution is an alkaline solution of 20 g / L triethanolamine, and the pH is controlled at 10.5; the aeration and cleaning time is 10 minutes.

[0076] The experimental groups were:

[0077] Group A: After electrolytic manganese is removed from the tank, it is first soaked in desulfurization solution for 2 minutes, followed by plate passivation, aeration cleaning, and drying. Other processes are the same.

[0078] Group B: After the electrolytic manganese is removed from the tank, it is first rinsed with desulfurization solution for 2 minutes, followed by plate passivation, aeration cleaning, and drying. Other procedures are the same.

[0079] Group C: After the electrolytic manganese is removed from the tank and the aggregate plate is passivated, it is immediately soaked in desulfurization solution for 2 minutes, followed by aeration cleaning and drying. Other procedures are the same.

[0080] Group D: After electrolytic manganese is removed from the tank, it is plated, passivated, and aerated for cleaning. Then it is soaked in desulfurization solution for 2 minutes and then dried. Other procedures are the same.

[0081] The other processes and operations are the same as in Example 2, and the results are as follows:

[0082] The sulfur content and carbon content of Group A products are both 0.009%.

[0083] The sulfur content in Group B products is 0.011%, and the carbon content is 0.009%.

[0084] The sulfur content in group C products is 0.009%, and the carbon content is 0.008%.

[0085] The sulfur content in group D products is 0.010%, and the carbon content is 0.008%.

[0086] Comparative Example 1

[0087] Compared to Example 1, the only difference is that soaking in a rinsing solution was not used. Subsequent processes such as plate passivation, aeration cleaning, and drying were directly performed. The resulting product was metallic manganese with a sulfur content of 0.049% and a carbon content of 0.013%.

[0088] Comparative Example 2

[0089] Compared with Example 1, the only difference is that the rinsing solution is changed to an aqueous sodium hydroxide solution with a pH of 13.0.

[0090] All other operations and parameters were the same as in Example 1. The resulting manganese metal product contained 0.021% sulfur and 0.010% carbon.

[0091] Comparative Example 3

[0092] Compared to Example 1, the only difference is that the rinsing solution was changed to an aqueous solution of sodium hydroxide with a pH of 10.5. All other operations and parameters are the same as in Example 1.

[0093] All other operations and parameters were the same as in Example 1. The resulting manganese metal product contained 0.030% sulfur and 0.012% carbon.

Claims

1. A method for reducing the content of sulphur-containing inorganic salts and / or sulphur-containing organic substances in electrolytic manganese, characterized in that, The electrolytic manganese is obtained by electrolysis, and the electrolytic manganese is contacted with a sulfur-reducing solution to reduce the content of sulfur-containing inorganic salt and / or sulfur-containing organic matter in the electrolytic manganese, thereby obtaining sulfur-reduced electrolytic manganese. The sulfur-reducing solution is an alkaline solution with pH≥10, and the alkaline solution contains a quality improver. The quality improver includes one or more of water-soluble organic amine, organic carboxylic acid source, silicate, water-soluble zinc salt, and soluble aluminum source. The sulfur-containing inorganic salt includes at least one of sulfate and sulfide.

2. The method of claim 1, wherein, The sulfate includes at least one of ammonium sulfate, manganese sulfate, and magnesium sulfate. The sulfide includes at least one of sodium sulfide, ammonium sulfide, potassium sulfide, and calcium sulfide. The sulfur-containing organic matter includes sodium dimethyl dithiocarbamate.

3. The method of claim 1, wherein, The organic amine includes alcohol amine, and further includes at least one of ethanol amine, ethylenediamine, and triethanolamine. Preferably, the soluble aluminum source includes at least one of aluminic acid, aluminic acid salt, aluminum nitrate, aluminum sulfate, aluminum chloride, and organic aluminum salt. Preferably, the zinc salt includes at least one of zinc nitrate, zinc sulfate, zinc chloride, and sodium zincate. Preferably, the silicate includes at least one of sodium silicate, potassium silicate, potassium aluminum silicate, sodium potassium aluminum silicate, and lithium silicate. Preferably, the organic carboxylic acid source includes water-soluble C2-C18 mono- or poly-carboxylic acid salt, and further includes alcohol-containing diacid, and further includes tartaric acid and its salt.

4. The method of claim 3, wherein, The quality improver includes organic amine, soluble aluminum source, and organic carboxylic acid source, and further preferably includes alcohol amine, soluble aluminum source, and alcohol-containing diacid. Preferably, the weight ratio of the organic amine, the soluble aluminum source, and the organic carboxylic acid source in the quality improver is 1-4:1-2:

1.

5. The method according to any one of claims 1 to 4, characterized in that, The concentration of the quality improver in the sulfur-reducing solution is 0.1-350 g / L, and further preferably 0.5-100 g / L.

6. The method of claim 1, wherein, The alkaline component in the sulfur-reducing solution includes at least one of sodium hydroxide, potassium hydroxide, and ammonia.

7. The method of claim 1, wherein, The pH of the sulfur-reducing solution is 10-13.8, and preferably 12-13.

8. The method according to any one of claims 1 to 7, characterized in that, The electrolytic manganese is subjected to plate gathering, passivation, and aeration cleaning after being discharged from the electrolysis tank. The electrolytic manganese is contacted with the sulfur-reducing solution before, during, or after at least one of the plate gathering, the passivation, and the aeration cleaning. Preferably, the electrolytic manganese is subjected to rinsing, plate gathering, passivation, and aeration cleaning after being discharged from the electrolysis tank, and any of the rinsing and the plate gathering is performed in the sulfur-reducing solution.

9. The method of claim 1, wherein, The residence time of the electrolytic manganese in the sulfur-reducing solution is more than 5 seconds.

10. The method of claim 1, wherein, The temperature of the electrolytic manganese in the sulfur-reducing solution is 10-80°C.