Method for reducing sulfur content of unqualified electrolytic manganese metal

Abstract

The invention discloses a method for reducing the sulfur content of unqualified electrolytic manganese metal, which comprises the following steps: (1) carrying out immersion cleaning on the electrolytic manganese metal with the sulfur content exceeding the standard by using water for 1-5 times, and obtaining the primarily cleaned electrolytic manganese metal after the immersion cleaning is completed; (2) carrying out immersion cleaning on the electrolytic manganese metal subjected to primary cleaning by using an oxalic acid solution to obtain the electrolytic manganese metal subjected to secondary cleaning after immersion cleaning is completed; (3) carrying out immersion cleaning on the electrolytic manganese metal subjected to secondary cleaning by using an alkaline solution, and obtaining the electrolytic manganese metal subjected to tertiary cleaning after immersion cleaning is completed; and (4) the electrolytic manganese metal subjected to third-time washing is washed with clear water, and qualified electrolytic manganese metal is obtained. The method can effectively solve the problem that the sulfur content in the electrolytic manganese metal exceeds the standard due to the fact that the electrolytic manganese metal is soaked in the passivation solution with high ammonium sulfate for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic manganese production, in particular to a method for reducing the sulfur content of unqualified electrolytic metal manganese. Background Art

[0002] Electrolytic manganese metal has high purity and can increase the hardness of alloy materials. It is one of the indispensable raw materials for the steel industry, aluminum alloy industry, magnetic material industry, chemical industry, etc. Electrolytic manganese metal is obtained by acid leaching manganese ore to obtain manganese salt solution, which is then sent to the electrolytic cell for electrolysis to precipitate the electrolytic product. After the electrolytic product is passivated, washed, dried, stripped, etc., the electrolytic manganese metal product is obtained.

[0003] In the post-electrolysis process, the manganese produced by passivation is an important component of electrolytic manganese products. Sulfur is a common element in manganese products, and the sulfur content of the product is one of the key indicators affecting the quality of electrolytic manganese products. However, in manganese, the sulfur content often exceeds 0.05wt%, which exceeds the index range. After analyzing the reasons, it is mainly: the manganese is not collected in time, and the manganese falls into the passivation barrel during the passivation process of the product. Due to long-term immersion in the passivation solution with high ammonium sulfate, the surface and gaps of the manganese metal are surrounded by ammonium sulfate during the oxidation and passivation process, and the rinsing process cannot be washed out, which leads to the electrolytic manganese with excessive sulfur content, that is, the electrolytic manganese with unqualified quality.

[0004] In order to improve the product quality of electrolytic manganese metal, it is necessary to study a method to reduce the sulfur content of unqualified electrolytic manganese metal. Summary of the invention

[0005] The invention provides a method for reducing the sulfur content of unqualified electrolytic manganese metal, which can effectively solve the problem of excessive sulfur content in electrolytic manganese metal caused by long-term immersion in a passivation solution with high ammonium sulfate.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A method for reducing the sulfur content of unqualified electrolytic manganese metal comprises the following steps:

[0008] (1) washing the electrolytic manganese metal with excessive sulfur content with water for 1 to 5 times, each washing time being 5 to 120 minutes, and obtaining washed electrolytic manganese metal after the washing is completed;

[0009] (2) the electrolytic manganese metal after the primary washing is leached with an oxalic acid solution for 5 to 120 minutes, and after the leaching is completed, the electrolytic manganese metal after the secondary washing is obtained;

[0010] (3) the electrolytic manganese metal after the second washing is then washed with an alkaline solution for 5 to 120 minutes, and after the washing is completed, the electrolytic manganese metal after the third washing is obtained;

[0011] (4) After the three washes, the electrolytic manganese metal is washed with clean water to obtain qualified electrolytic manganese metal.

[0012] Preferably, in step (1), the water is hot water at a temperature of 60 to 100°C.

[0013] Preferably, in step (2), the concentration of the oxalic acid solution is 5 to 30 g / L.

[0014] Preferably, in step (2), after the leaching with the oxalic acid solution is completed, it is then washed with water for 1-3 times to obtain electrolytic manganese metal after the second washing.

[0015] Preferably, in step (2), the immersion temperature is 20 to 80°C.

[0016] Preferably, in step (3), the alkaline solution is aqueous ammonia solution, sodium hydroxide solution or potassium hydroxide solution.

[0017] Preferably, in step (3), the concentration of the alkaline solution is 0.1 to 20 g / L.

[0018] Preferably, in step (3), the immersion temperature is 20 to 80°C.

[0019] Preferably, in step (4), the washing method is immersion, immersion in clean water 1 to 5 times, and the immersion time is 1 to 120 minutes.

[0020] Preferably, in step (4), the washing temperature is 20 to 100°C.

[0021] Preferably, in step (1) and / or step (2) and / or step (3) and / or step (4), a stirring operation is performed during the cleaning process.

[0022] Preferably, the sulfur content in the electrolytic manganese metal with excessive sulfur content exceeds 0.05wt% and does not exceed 0.8wt%.

[0023] Preferably, in step (1), the amount of water used is sufficient to completely immerse the electrolytic manganese metal.

[0024] Preferably, in step (2), the amount of oxalic acid solution used is suitable for completely soaking the electrolytic manganese metal.

[0025] Preferably, in step (3), the amount of alkaline solution used is suitable for completely soaking the electrolytic manganese metal.

[0026] The above-mentioned method for reducing the sulfur content of unqualified electrolytic manganese is to firstly reduce the sulfur and carbon in the unqualified electrolytic manganese by immersion in water, and then use oxalic acid solution to react with the sulfur in the electrolytic manganese to remove the sulfur. However, during the use of oxalic acid solution, a part of oxalic acid and oxalate will crystallize on the electrolytic manganese, so that the carbon content of the electrolytic manganese is generally increased. Therefore, an alkaline solution is used to reduce the carbon in the electrolytic manganese, and finally the oxalate, alkali, sulfur and carbon remaining on the surface of the electrolytic manganese are washed with water, so that the sulfur content and carbon content in the electrolytic manganese product can meet the standard requirements.

[0027] The present invention has the following advantages:

[0028] (1) The present invention uses water, oxalic acid, alkali solution and water to wash unqualified electrolytic manganese metal in sequence, which can achieve the purpose of reducing the sulfur content in unqualified electrolytic manganese metal, and the electrolytic manganese metal can show good metallic luster, thereby effectively improving the quality of electrolytic manganese metal.

[0029] (2) The process of the present invention is simple, easy to operate, and low in cost, which can greatly increase the price of electrolytic manganese metal and has significant economic benefits. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] A method for reducing the sulfur content of unqualified electrolytic manganese metal comprises the following steps:

[0032] (1) washing electrolytic manganese metal with excessive sulfur content with water for 1 to 5 times (e.g., 1 time, 2 times, 3 times, 4 times or 5 times), each washing time being 5 to 120 minutes (e.g., 5 minutes, 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes or 120 minutes), and obtaining washed electrolytic manganese metal after washing;

[0033] (2) the electrolytic manganese metal after the primary washing is leached with an oxalic acid solution for a leaching time of 5 to 120 minutes (e.g., 5 minutes, 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes or 120 minutes), and after the leaching is completed, the electrolytic manganese metal after the secondary washing is obtained;

[0034] (3) the electrolytic manganese metal after the second washing is then leached with an alkaline solution for 5 to 120 minutes (e.g., 5 minutes, 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes or 120 minutes), and after the leaching is completed, the electrolytic manganese metal after the third washing is obtained;

[0035] (4) After the three washes, the electrolytic manganese metal is washed with clean water to obtain qualified electrolytic manganese metal.

[0036] This embodiment provides a method for reducing the sulfur content of unqualified electrolytic manganese metal, which comprises firstly washing with water to preliminarily reduce the sulfur and carbon in the unqualified electrolytic manganese metal, and then using an oxalic acid solution to react with the sulfur in the electrolytic manganese metal to remove the sulfur. However, during the use of the oxalic acid solution, a portion of oxalic acid and oxalate will crystallize on the electrolytic manganese metal, causing the carbon content of the electrolytic manganese metal to generally increase. Therefore, an alkaline solution is then used to reduce the carbon in the electrolytic manganese metal, and finally, water is used to wash the oxalate, alkali, sulfur and carbon remaining on the surface of the electrolytic manganese metal, so that the sulfur content and carbon content in the electrolytic manganese metal product can meet the standard requirements.

[0037] Wherein, in step (2), oxalic acid solution is used to wash electrolytic manganese metal. Compared with dilute hydrochloric acid, dilute hydrochloric acid has the following defects: a. The content of chloride ions in the electrolytic solution is increased, and the increase of chloride ions will aggravate the corrosion of the triple point of the anode plate in the electrolytic production process; b. The increase of chloride ions will produce more hydrogen chloride gas during the acid injection process of liquid production, which poses a great safety hazard to the production site, and the increase of chloride ions will also cause more serious corrosion to the steel liquid tank and liquid groove; c. After washing with dilute hydrochloric acid, the surface of the electrolytic manganese metal taken out tends to turn black. Compared with dilute sulfuric acid, dilute sulfuric acid itself contains sulfur and has a poor effect in reducing sulfur. Compared with hydrogen peroxide, hydrogen peroxide requires a higher concentration to achieve a better oxidation effect, has a higher cost, and the sulfur reduction effect is not as good as oxalic acid.

[0038] In some preferred embodiments of the present invention, in step (1), the water is hot water having a temperature of 60 to 100° C. (e.g., 60° C., 70° C., 80° C., 85° C., 90° C. or 100° C.).

[0039] In some preferred embodiments of the present invention, in step (2), the concentration of the oxalic acid solution is 5 to 30 g / L (e.g., 5 g / L, 10 g / L, 15 g / L, 16.67 g / L, 20 g / L, 25 g / L or 30 g / L).

[0040] In some preferred embodiments of the present invention, in step (2), after the leaching with the oxalic acid solution is completed, it is then washed with water for 1-3 times to obtain the electrolytic manganese metal after the second washing. The water washing can wash away part of the oxalate ions, and the water containing the oxalate ions can continue to leaching the unqualified electrolytic manganese metal.

[0041] In some preferred embodiments of the present invention, in step (2), the immersion temperature is 20-80°C (eg, room temperature, 20°C, 30°C, 50°C, 60°C or 80°C).

[0042] In some preferred embodiments of the present invention, in step (3), the alkaline solution is an aqueous ammonia solution, a sodium hydroxide solution or a potassium hydroxide solution, wherein the sodium hydroxide solution is the most preferred.

[0043] In some preferred embodiments of the present invention, in step (3), the concentration of the alkaline solution is 0.1-20 g / L (e.g., 0.1 g / L, 1 g / L, 5 g / L, 10 g / L, 15 g / L or 20 g / L).

[0044] In some preferred embodiments of the present invention, in step (3), the immersion temperature is 20-80°C (eg, room temperature, 20°C, 30°C, 50°C, 60°C or 80°C).

[0045] In some preferred embodiments of the present invention, in step (4), the washing method is immersion, immersing in clean water 1 to 5 times, and the immersion time is 1 to 120 minutes (for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90 minutes or 120 minutes).

[0046] In some preferred embodiments of the present invention, in step (4), the washing temperature is 20-100°C (eg, room temperature, 20°C, 30°C, 50°C, 70°C, 80°C or 100°C).

[0047] In some preferred embodiments of the present invention, in step (1) and / or step (2) and / or step (3) and / or step (4), the immersion process may be accompanied by a stirring operation, and the stirring speed may be 50-300 r / min (e.g., 50 r / min, 100 r / min, 150 r / min, 200 r / min or 300 r / min).

[0048] In some preferred embodiments of the present invention, the sulfur content in the electrolytic manganese metal with excessive sulfur content exceeds 0.05% and does not exceed 0.8%.

[0049] In some preferred embodiments of the present invention, in step (1), the amount of water used is preferably sufficient to completely immerse the electrolytic manganese metal.

[0050] In some preferred embodiments of the present invention, in step (2), the amount of oxalic acid solution used is preferably sufficient to completely immerse the electrolytic manganese metal.

[0051] In some preferred embodiments of the present invention, in step (3), the amount of alkaline solution used is preferably sufficient to completely immerse the electrolytic manganese metal.

[0052] The present embodiment provides a method for reducing the sulfur content of unqualified electrolytic manganese metal, which can achieve the purpose of reducing the sulfur content in unqualified electrolytic manganese metal by washing unqualified electrolytic manganese metal with water, oxalic acid, alkali solution and water in sequence, and the electrolytic manganese metal can show good metallic luster, thereby effectively improving the quality of electrolytic manganese metal. The process route of the present invention is simple, easy to operate, and low in cost, which can greatly increase the price of electrolytic manganese metal and has significant economic benefits.

[0053] The present invention will be further described below by way of examples, but the protection scope of the present invention is not limited to these embodiments.

[0054] Example 1

[0055] A method for reducing the sulfur content of unqualified electrolytic manganese metal comprises the following steps:

[0056] (1) The electrolytic manganese metal with excessive sulfur content is washed twice with hot water at 80°C, each time for 5 minutes, and stirred at the same time, and after the washing is completed, the washed electrolytic manganese metal is obtained;

[0057] (2) The electrolytic manganese metal after the primary washing is soaked in a 16.67 g / L oxalic acid solution for 5 min, with stirring operation, and washed twice with water after the soaking, and the electrolytic manganese metal after the secondary washing is obtained after the washing;

[0058] (3) The electrolytic manganese metal after the second washing is then rinsed with a 5 g / L sodium hydroxide solution for 5 minutes with stirring. After the rinsing is completed, the electrolytic manganese metal after the third washing is obtained;

[0059] (4) After the three washes, the electrolytic manganese metal is washed twice with clean water at room temperature to obtain qualified electrolytic manganese metal.

[0060] Example 2

[0061] A method for reducing the sulfur content of unqualified electrolytic manganese metal comprises the following steps:

[0062] (1) The electrolytic manganese metal with excessive sulfur content is washed with hot water at 60° C. for 3 times, each time for 30 minutes, and after the washing is completed, the washed electrolytic manganese metal is obtained;

[0063] (2) the electrolytic manganese metal after the primary washing is soaked in a 10 g / L oxalic acid solution for 30 min, and then washed twice with water after the soaking, and the electrolytic manganese metal after the secondary washing is obtained after the washing;

[0064] (3) the electrolytic manganese metal after the second washing is then rinsed with a 10 g / L sodium hydroxide solution for 30 min, and after the rinsing is completed, the electrolytic manganese metal after the third washing is obtained;

[0065] (4) After the three washes, the electrolytic manganese metal is washed once with clean water at room temperature to obtain qualified electrolytic manganese metal.

[0066] Example 3

[0067] (1) The electrolytic manganese metal with excessive sulfur content is washed twice with hot water at 100° C., each washing time is 5 minutes, and stirring operation is performed at the same time, and after the washing is completed, the electrolytic manganese metal is obtained;

[0068] (2) the electrolytic manganese metal after the primary washing is soaked in a 20 g / L oxalic acid solution for 5 min, with stirring operation, and after the soaking is completed, it is washed twice with water, and after the washing is completed, the electrolytic manganese metal after the secondary washing is obtained;

[0069] (3) The electrolytic manganese metal after the second washing is then rinsed with a 20 g / L potassium hydroxide solution for 5 minutes with stirring. After the rinsing is completed, the electrolytic manganese metal after the third washing is obtained;

[0070] (4) After the three washes, the electrolytic manganese metal is washed three times with clean water at room temperature to obtain qualified electrolytic manganese metal.

[0071] Example 4

[0072] Example 4 is substantially the same as Example 1, but the concentration of oxalic acid is 40 g / L.

[0073] Example 5

[0074] Example 5 is basically the same as Example 1, but in step (1), the water temperature is room temperature, 25°C.

[0075] The method of the above-mentioned embodiments 1-4 was used to treat the unqualified electrolytic manganese metal sample 1 with excessive sulfur content (manganese content of 88.25%, sulfur content of 0.580%, carbon content of 0.191%), and the method of embodiment 5 was used to treat the unqualified electrolytic manganese metal sample 2 with excessive sulfur content (manganese content of 90.56%, sulfur content of 0.182%, carbon content of 0.150%). In each treatment, 300g of unqualified electrolytic manganese metal was taken. In steps (1)-(3), the amount of immersion liquid used each time was 600mL. The main reasons for the excessive sulfur content were that the manganese on the ground was not collected in time, and the manganese on the ground fell into the passivation barrel during the passivation process of the product. Due to long-term immersion in the passivation solution with high ammonium sulfate, the surface and gaps of the manganese metal were surrounded by ammonium sulfate during the oxidation and passivation process, and could not be washed out during the rinsing process, resulting in the electrolytic manganese metal with excessive sulfur content, that is, the electrolytic manganese metal with unqualified quality.

[0076] The desulfurization effect is shown in Table 1 (the following percentages are all weight percentages):

[0077] Table 1

[0078]

[0079]

Claims

1. A method for reducing the sulfur content of unqualified electrolytic manganese metal, characterized in that The following steps are involved: (1) The electrolytic manganese metal with excessive sulfur content is washed with water for 1 to 5 times, each washing time is 5 to 120 minutes, and after the washing is completed, the washed electrolytic manganese metal is obtained; (2) The electrolytic manganese metal after the primary washing is soaked in oxalic acid solution for 5 to 120 minutes, and after the soaking is completed, the electrolytic manganese metal after the secondary washing is obtained; (3) The electrolytic manganese metal after the second washing is then washed with an alkaline solution for 5 to 120 minutes. After the washing is completed, the electrolytic manganese metal after the third washing is obtained; (4) After the three washes, the electrolytic manganese metal is washed with clean water to obtain qualified electrolytic manganese metal.

2. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1, characterized in that: In step (1), the water is hot water with a temperature of 60-100°C.

3. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1, characterized in that: In step (2), the concentration of the oxalic acid solution is 5-30 g / L.

4. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1 or 3, characterized in that: In step (2), after the leaching with the oxalic acid solution is completed, it is then washed with water for 1-3 times to obtain electrolytic manganese metal after the second washing.

5. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1, characterized in that: In step (3), the alkaline solution is an aqueous ammonia solution, a sodium hydroxide solution or a potassium hydroxide solution.

6. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1 or 5, characterized in that: In step (3), the concentration of the alkaline solution is 0.1-20 g / L.

7. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1, characterized in that: In step (4), the washing method is immersion, immersion in clean water 1 to 5 times, and the immersion time is 1 to 120 minutes.

8. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1 or 7, characterized in that: In step (4), the washing temperature is 20-100°C.

9. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1 or 8, characterized in that: In step (1) and / or step (2) and / or step (3) and / or step (4), stirring is performed during the cleaning process.

10. The method for reducing the sulfur content of unqualified electrolytic manganese metal according to claim 1, characterized in that: The sulfur content of the electrolytic manganese metal exceeding the standard exceeds 0.05wt% and does not exceed 0.8wt%.

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