A method for electrolytic refining of high-purity metallic manganese

Abstract

The invention discloses a method for electrolytic refining of high-purity metallic manganese. Metallic manganese is used as an anode, a ruthenium-plated titanium plate is used as a cathode, and a manganese sulfate aqueous solution is used as a starting electrolyte. The cathode and the anode are separated by a diaphragm cloth, and the power supply is turned on to electrolyze to obtain a manganese sulfate solution. The manganese sulfate solution is sequentially reduced by hydrogen peroxide under acidic conditions, ferric sulfate is precipitated to remove potassium and sodium ions, and manganese fluoride is precipitated and filtered to remove calcium and magnesium ions. The solution is introduced into the cathode area of ​​the electrolytic cell, and the manganese sulfate solution flows from the cathode area to the anode area. The liquid level in the cathode area is higher than that in the anode area. The temperature, cell voltage, and current density are set to electrolyze to obtain high-purity metallic manganese. The invention has the technical advantages of high purity of metallic manganese, less impurities, stable quality, and simple process.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy, and in particular relates to a method for electrolytically refining high-purity metallic manganese. Background Art

[0002] Ultra-high purity metal / alloy targets for integrated circuit manufacturing are the basic materials for my country's information industry and are a high-tech product with high technical difficulty and added value that is supported by the state. However, due to its complex preparation process and high technical threshold, only a few manufacturers in developed countries such as the United States, Japan and Germany have achieved mass production, and the price is very expensive.

[0003] The patent with application publication number 202110588463.4 discloses a method for electrolytically depositing high-purity manganese from manganese chloride electrolytic solution. A manganese chloride solution is prepared, and colloidal sulfur is added to the prepared manganese chloride solution. The mass volume concentration of the colloidal sulfur is 10-14g / L. The solution is fully stirred and mixed at room temperature, and the pH value of the solution is adjusted to 5.0 with ammonia water to obtain an electrolytic solution; the electrolytic solution is then poured into an electrolytic tank, and the temperature of the electrolytic tank, the DC current density of the cathode plate and the anode plate, and the electrolytic voltage are adjusted. After electrolysis for 24 hours, high-purity manganese with a purity of 99.99-99.999% can be obtained. This technology uses high-purity manganese chloride and high-purity ammonium chloride as raw materials to prepare a solution, adds colloidal sulfur as an additive or adds a composite additive mainly composed of colloidal sulfur to replace the toxic selenium dioxide or sulfur dioxide added to the traditional electrolytic manganese solution, and prepares high-purity manganese with a purity of 99.99-99.999%. The process is short, easy to operate, green and environmentally friendly, and meets the requirements of clean production, but this process has not been applied industrially. Summary of the invention

[0004] The object of the present invention is to provide a method for electrolytically refining high-purity metallic manganese, which overcomes the problem of no electrolytic refining of high-purity manganese in the prior art.

[0005] The technical solution of the present invention is a method for electrolytic refining of high-purity metallic manganese, comprising the following steps:

[0006] (1) using metallic manganese as an anode, gold, amber, ruthenium or a ruthenium-plated titanium plate as a cathode, and an aqueous solution of manganese sulfate as a starting electrolyte, wherein the cathode and the anode are separated by a diaphragm cloth, and a direct current power supply is applied for electrolysis to obtain a manganese sulfate solution;

[0007] (2) adding dilute sulfuric acid and hydrogen peroxide to the manganese sulfate solution in step (1) to reduce the high-valent manganese in the solution to divalent manganese ions;

[0008] (3) adding ferric sulfate to the solution in step (2), stirring and precipitating, and filtering to remove potassium and sodium ions;

[0009] (4) adding manganese fluoride to the solution in step (3), stirring and precipitating, and filtering to remove calcium and magnesium ions;

[0010] (5) adding ammonium sulfate, ammonia water and deionized water to the solution in step (4) to adjust the manganese ion concentration to 10-50 g / L, the ammonium sulfate concentration to 80-120 g / L, the pH value to 7-7.5, setting the temperature to 40-60° C., introducing the solution into the cathode area of ​​the electrolytic cell, the liquid level in the cathode area is 1-5 cm higher than that in the anode area, the manganese sulfate solution flows from the cathode area to the anode area, turning on the power supply for electrolysis, and obtaining high-purity metallic manganese at the cathode.

[0011] In the above-mentioned method for electrolytic refining of high-purity metallic manganese, the concentration of manganese sulfate is 10-50 g / L.

[0012] In the above-mentioned method for electrolytic refining of high-purity metallic manganese, in step (2), hydrogen peroxide is added until no high-valent manganese ions are detected in the solution.

[0013] In the above-mentioned method for electrolytic refining of high-purity metallic manganese, in step (3), the molar ratio of the total amount of potassium and sodium ions in the solution to the amount of iron sulfate is 1:3.

[0014] In the above-mentioned method for electrolytic refining of high-purity metallic manganese, in step (4), the ratio of the total amount of calcium and magnesium ions in the solution to the amount of manganese fluoride substance is 1:2.

[0015] In the above-mentioned method for electrolytic refining of high-purity metallic manganese, in step (5), the manganese ion concentration in the adjusted solution is 10-50 g / L, the ammonium sulfate concentration is 90-110 g / L, the pH value is 7-7.5, the temperature is set to 40-50° C., the electrolytic cell voltage is 0.1-10 V, and the cathode current density is 200-500 A / m 2 .

[0016] The reducing agent used to reduce high-valent manganese to divalent manganese ions is hydrogen peroxide, and the reaction principle is as follows:

[0017] 2KMnO4+5H2O2+3H2SO4=K2SO4+2MnSO4+5O2↑+8H2O

[0018] MnO2+H2O2+H2SO4→MnSO4+O2↑+2H2O

[0019] Ferric sulfate is used to filter and remove potassium and sodium ions. The molar ratio of potassium, sodium and iron is 1:3. The reaction principle is as follows:

[0020] K2SO4+3Fe2(SO4)3+12H2O→2KFe3[SO4(OH)3]2↓+6H2(SO4)3

[0021] Na2SO4+3Fe2(SO4)3+12H2O→2NaFe3[SO4(OH)3]2↓+6H2(SO4)3

[0022] Manganese fluoride is used to precipitate and remove calcium and magnesium ions. The molar ratio of calcium and magnesium ions to fluoride ions is 1:2. The reaction principle is as follows:

[0023] Ca 2+ +MnF2→CaF2↓+Mn 2+

[0024] Mg 2+ +MnF2→MgF2↓+Mn 2+

[0025] To achieve the purpose of the present invention, the present invention adopts a mobile phase electrolytic cell with metallic manganese as an anode and a ruthenium-plated titanium plate as a cathode, and prepares metallic manganese with a purity of 99.99-99.999% by reduction conversion and precipitation and impurity removal.

[0026] The applicant discovered during the experiment and industrial production research that the main metal impurity elements contained in metallic manganese are potassium, sodium, magnesium, calcium, zinc, iron and nickel. The present invention uses metallic manganese as the anode. Metallic zinc, iron and nickel with a metal reducibility lower than that of manganese will not discharge at the anode and exist in the form of single anode mud; potassium, sodium, magnesium and calcium will exist in the anode liquid in the form of sulfate. The present invention uses hydrogen peroxide to reduce high-valent manganese elements, uses iron sulfate to precipitate sodium ions and potassium ions, and uses manganese fluoride to precipitate magnesium ions and calcium ions to obtain manganese sulfate solution, and then obtains metallic manganese after electrolysis. Compared with the prior art, the present invention has the following advantages:

[0027] The basic principle of this method is to use the different potential series of metallic manganese and impurities to separate and purify. ① Using metallic manganese as the anode, under the action of direct current, the metallic manganese on the anode enters the electrolyte in an ionic state and is electrochemically precipitated on the cathode after purification to become cathode manganese (electrolytic refined manganese). Metallic zinc, iron and nickel with less metal reducibility than manganese will not discharge at the anode and will be precipitated and recovered in the form of single anode mud. ② Potassium, sodium, magnesium and calcium will exist in the anode liquid in the form of sulfate. Sodium ions and potassium ions are precipitated with iron sulfate, and magnesium ions and calcium ions are precipitated with manganese fluoride. The final metallic manganese product has high purity, which can reach 99.99%-99.999%, and can be used as ultra-high purity metal / alloy target. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with embodiments and comparative examples, but they are not intended to limit the present invention.

[0029] Embodiment. A method for electrolytic refining of high-purity metallic manganese comprises the following steps:

[0030] (1) using metallic manganese as an anode, gold, amber, ruthenium or a ruthenium-plated titanium plate as a cathode, and an aqueous solution of manganese sulfate as a starting electrolyte, wherein the cathode and the anode are separated by a diaphragm cloth, and a direct current power supply is applied for electrolysis to obtain a manganese sulfate solution;

[0031] (2) adding dilute sulfuric acid and hydrogen peroxide to the manganese sulfate solution in step (1) to reduce the high-valent manganese in the solution to divalent manganese ions;

[0032] (3) adding ferric sulfate to the solution in step (2), stirring and precipitating, and filtering to remove potassium and sodium ions;

[0033] (4) adding manganese fluoride to the solution in step (3), stirring and precipitating, and filtering to remove calcium and magnesium ions;

[0034] (5) adding ammonium sulfate, ammonia water and deionized water to the solution in step (4) to adjust the manganese ion concentration to 10-50 g / L, the ammonium sulfate concentration to 80-120 g / L, the pH value to 7-7.5, setting the temperature to 40-60° C., introducing the solution into the cathode area of ​​the electrolytic cell, the liquid level in the cathode area is 1-5 cm higher than that in the anode area, the manganese sulfate solution flows from the cathode area to the anode area, turning on the power supply for electrolysis, and obtaining high-purity metallic manganese at the cathode.

[0035] Furthermore, the concentration of manganese sulfate is 10-50 g / L.

[0036] Furthermore, in step (2), hydrogen peroxide is added until no high-valent manganese ions are detected in the solution.

[0037] Furthermore, in step (3), the molar ratio of the total amount of potassium and sodium ions in the solution to the amount of ferric sulfate is 1:3.

[0038] Furthermore, in step (4), the ratio of the total amount of calcium and magnesium ions in the solution to the amount of manganese fluoride substance is 1:2.

[0039] Further, in step (5), the manganese ion concentration in the adjusted solution is 10-50 g / L, the ammonium sulfate concentration is 90-110 g / L, the pH value is 7-7.5, the temperature is set to 40-50°C, the electrolytic cell voltage is 0.1-10 V, and the cathode current density is 200-500 A / m 2 .

[0040] The technology of the present invention is described in more detail below with reference to specific examples.

[0041] Example 1

[0042] Manganese metal is used as the anode, ruthenium-plated titanium plate is used as the cathode, and manganese sulfate aqueous solution is used as the starting electrolyte. The cathode and anode are separated by a diaphragm cloth, and the power is turned on to electrolyze to obtain manganese sulfate solution. The manganese sulfate solution is successively reduced by hydrogen peroxide under acidic conditions, iron sulfate precipitation is used to remove potassium and sodium ions, manganese fluoride precipitation is filtered to remove calcium and magnesium ions, and ammonium sulfate and deionized water are added to adjust the manganese ion concentration to 35g / L, the ammonium sulfate concentration to 120g / L, and the pH value to 7.2. The solution is introduced into the cathode area of ​​the electrolytic cell, and the liquid level in the cathode area is 3cm higher than that in the anode area. The manganese sulfate solution flows from the cathode area to the anode area. The temperature is set to 40°C, the cell voltage is 4.2V, and the current density is 320A / m 2 The electrolysis was carried out for 24 hours, and the purity of the cathode metal manganese was measured to be 99.995%.

[0043] Example 2

[0044] Manganese metal is used as the anode, ruthenium-plated titanium plate is used as the cathode, and manganese sulfate aqueous solution is used as the starting electrolyte. The cathode and anode are separated by a diaphragm cloth, and the power is turned on to electrolyze to obtain manganese sulfate solution. The manganese sulfate solution is successively reduced by hydrogen peroxide under acidic conditions, iron sulfate precipitation is used to remove potassium and sodium ions, manganese fluoride precipitation is filtered to remove calcium and magnesium ions, and ammonium sulfate and deionized water are added to adjust the manganese ion concentration to 30g / L, the ammonium sulfate concentration to 100g / L, and the pH value to 7.0. The solution is introduced into the cathode area of ​​the electrolytic cell, and the liquid level in the cathode area is 1cm higher than that in the anode area. The manganese sulfate solution flows from the cathode area to the anode area. The temperature is set to 42°C, the cell voltage is 4.0V, and the current density is 300A / m 2 The electrolysis was carried out for 24 hours, and the purity of the cathode metal manganese was measured to be 99.996%.

[0045] Example 3

[0046] Manganese metal is used as the anode, ruthenium-plated titanium plate is used as the cathode, and manganese sulfate aqueous solution is used as the starting electrolyte. The cathode and anode are separated by a diaphragm cloth, and the power is turned on to electrolyze to obtain manganese sulfate solution. The manganese sulfate solution is successively reduced by hydrogen peroxide under acidic conditions, iron sulfate precipitation is used to remove potassium and sodium ions, manganese fluoride precipitation is filtered to remove calcium and magnesium ions, and ammonium sulfate and deionized water are added to adjust the manganese ion concentration to 40g / L, the ammonium sulfate concentration to 140g / L, and the pH value to 7.3. The solution is introduced into the cathode area of ​​the electrolytic cell, and the liquid level in the cathode area is 5cm higher than that in the anode area. The manganese sulfate solution flows from the cathode area to the anode area. The temperature is set to 45°C, the cell voltage is 4.3V, and the current density is 350A / m 2 The electrolysis was carried out for 24 hours, and the purity of the cathode metal manganese was measured to be 99.997%.

[0047] Example 4

[0048] Manganese metal is used as the anode, ruthenium-plated titanium plate is used as the cathode, and manganese sulfate aqueous solution is used as the starting electrolyte. The cathode and anode are separated by a diaphragm cloth, and the power is turned on to electrolyze to obtain manganese sulfate solution. The manganese sulfate solution flows from the cathode area to the anode area to obtain a manganese sulfate solution. The manganese sulfate solution is successively reduced by hydrogen peroxide under acidic conditions, iron sulfate is precipitated to remove potassium and sodium ions, manganese fluoride is precipitated and filtered to remove calcium and magnesium ions, and ammonium sulfate and deionized water are added to adjust the manganese ion concentration to 36g / L, the ammonium sulfate concentration to 115g / L, and the pH value to 7.3. The solution is introduced into the cathode area of ​​the electrolytic cell, and the liquid level in the cathode area is 4cm higher than that in the anode area. The manganese sulfate solution flows from the cathode area to the anode area. The temperature is set to 44°C, the cell voltage is 4.5V, and the current density is 360A / m 2 The electrolysis was carried out for 24 hours, and the purity of the cathode metal manganese was measured to be 99.997%.

[0049] Example 5

[0050] Manganese metal is used as the anode, ruthenium-plated titanium plate is used as the cathode, and manganese sulfate aqueous solution is used as the starting electrolyte. The cathode and anode are separated by a diaphragm cloth, and the power is turned on to electrolyze to obtain manganese sulfate solution. The manganese sulfate solution is successively reduced by hydrogen peroxide under acidic conditions, iron sulfate is precipitated to remove potassium and sodium ions, manganese fluoride is precipitated and filtered to remove calcium and magnesium ions, and ammonium sulfate and deionized water are added to adjust the manganese ion concentration to 45g / L, the ammonium sulfate concentration to 80g / L, and the pH value to 7.3. The solution is introduced into the cathode area of ​​the electrolytic cell, and the manganese sulfate solution flows from the cathode area to the anode area. The liquid level in the cathode area is 2cm higher than that in the anode area. The temperature is set to 42°C, the cell voltage is 4.4V, and the current density is 360A / m 2 The electrolysis was carried out for 24 hours, and the purity of the cathode metal manganese was measured to be 99.999%.

Claims

1. A method for electrolytic refining of high-purity metallic manganese, characterized in that: The steps include: (1) Using metallic manganese as the anode, gold, amber, ruthenium or ruthenium-plated titanium plate as the cathode, and manganese sulfate aqueous solution as the starting electrolyte, the cathode and the anode are separated by a diaphragm cloth, and a direct current power supply is applied for electrolysis to obtain a manganese sulfate solution; (2) adding dilute sulfuric acid and hydrogen peroxide to the manganese sulfate solution in step (1) to reduce the high-valent manganese in the solution to divalent manganese ions; adding hydrogen peroxide until no high-valent manganese ions are detected in the solution; (3) adding ferric sulfate to the solution in step (2), stirring and precipitating, and filtering to remove potassium and sodium ions; (4) adding manganese fluoride to the solution in step (3), stirring and precipitating, and filtering to remove calcium and magnesium ions; (5) Add ammonium sulfate, ammonia water and deionized water to the solution of step (4) to adjust the manganese ion concentration in the solution to 10-50 g / L, the ammonium sulfate concentration to 90-110 g / L, the pH value to 7-7.5, set the temperature to 40-50°C, the electrolytic cell voltage to 0.1-10 V, and the cathode current density to 200-500 A / m 2 The solution is introduced into the cathode area of ​​the electrolytic cell. The liquid level in the cathode area is 1-5 cm higher than that in the anode area. The manganese sulfate solution flows from the cathode area to the anode area. The power supply is turned on for electrolysis, and high-purity metallic manganese is obtained at the cathode.

2. The method for electrolytic refining of high-purity metallic manganese according to claim 1, characterized in that: In step (3), the molar ratio of the total amount of potassium and sodium ions in the solution to the amount of iron sulfate is 1:

3.

3. The method for electrolytic refining of high-purity metallic manganese according to claim 1, characterized in that: In step (4), the ratio of the total amount of calcium and magnesium ions in the solution to the amount of manganese fluoride substance is 1:2.