A method for removing fluorine from high-purity manganese sulfate by fluorination and a fluorine removal system

Abstract

The present invention discloses a method and a system for defluorination of high-purity manganese sulfate by impurity removal through fluorination. The method of the present invention uses a high-purity manganese sulfate solution obtained by impurity removal through fluorination as a raw material, concentrated sulfuric acid as a reactant, and high-temperature steam as a stripping gas. After stripping in a stripping tower, the defluorination of the high-purity manganese sulfate obtained by impurity removal through fluorination is completed; wherein, the interior of the stripping tower is in a vacuum environment. The system of the present invention is composed of a manganese sulfate solution raw material storage tank, a concentrated sulfuric acid storage tank, a stripping tower, a steam distribution cylinder, a defluorinated manganese sulfate solution storage tank, a gas condenser, a hydrofluoric acid storage tank, and a vacuum unit. The present invention first applies the stripping method to the defluorination of manganese sulfate solution. Through the method of the present invention, the removal of fluorine in the manganese sulfate solution can be achieved, and the phenomena of supersaturation of the manganese sulfate solution and crystallization due to reduced solubility will not occur. It has the characteristics of simple process, low treatment cost, high defluorination purity, and no introduction of new impurities; and the system of the present invention has the characteristics of reasonable design, energy conservation and consumption reduction.

Description

Technical Field

[0001] The present invention relates to a method for defluorinating high-purity manganese sulfate and a defluorination system, in particular to a method for defluorinating high-purity manganese sulfate by a fluorination method for impurity removal and a defluorination system. Background Art

[0002] Manganese sulfate is a precursor for preparing the cathode material of nickel-cobalt-manganese lithium batteries. At present, in-depth impurity removal of manganese sulfate solution to produce battery-grade manganese sulfate suitable for battery cathode materials is a research hotspot.

[0003] The specific standard of battery-grade manganese sulfate is that the sum of the concentrations of calcium and magnesium impurities is required to be ≤ 0.05%. However, the physical and chemical properties of calcium and magnesium ions are similar to those of manganese, making it difficult to remove them. Since the solubility of calcium fluoride and magnesium fluoride formed by calcium, magnesium ions and fluoride ions is relatively low, while the solubility of manganese fluoride is relatively high, currently manganese fluoride is generally used as a calcium and magnesium ion impurity remover in industry to complete the removal of calcium and magnesium impurities in manganese sulfate solution.

[0004] However, the reaction conditions for removing calcium and magnesium by manganese fluoride are as follows: when the pH value is small, hydrogen ions in the solution will react with fluoride to form HF due to acid effect; when pH ≥ 4, the reaction mainly forms fluoride precipitates, and as the pH value increases, the purification effect of calcium and magnesium ions gradually increases. When the dosage of manganese fluoride is 1.5 times the theoretical dosage, the precipitation rates of calcium and magnesium ions are 93% and 91% respectively; when the dosage is 2.5 times the theoretical dosage, the precipitation rates of calcium and magnesium ions can reach 99% and 98%.

[0005] Although the fluorination method achieves the purpose of removing calcium and magnesium impurities in manganese sulfate solution, due to the addition of excessive manganese fluoride, a large amount of fluoride ions will be introduced into the manganese sulfate solution treated by the fluorination method, and the concentration can even reach as high as 3000 ppm; and fluoride ions will corrode production equipment and seriously affect the performance of lithium batteries. Therefore, it is necessary to purify the fluoride therein.

[0006] Currently, the common defluorination process technologies for manganese sulfate solution treated by the fluorination method are: (1) ion exchange method, which removes fluoride ions by exchanging fluoride ions with anions in the resin; however, the resin maintenance cost of this method is high, and it is difficult to remove when the fluoride concentration in the solution exceeds 2000 ppm; (2) defluorinating agent method, which removes fluoride ions by a flocculation precipitation method; however, this method will introduce new impurities, and the purity can only reach 2000 ppm; (3) extraction method, the defluorination effect is better, and it can reach 10 ppm; however, a defluorinating agent needs to be used in the early stage to reduce the fluoride content to below 2 g / L before extraction, and the cost is very high.

[0007] The stripping method is a common method for defluorination in the chemical industry. It mainly relies on high-temperature gas to evaporate and blow out hydrogen fluoride gas in the solution, thereby realizing the separation of hydrogen fluoride in the solution. Compared with traditional ion exchange methods, defluorinating agent methods, and extraction methods, it has the advantages of simple process, low treatment cost, high defluorination purity, and no introduction of new impurities. Therefore, it is widely used in the defluorination process in the chemical industry.

[0008] However, due to the fact that fluorine in the manganese sulfate solution does not exist in the form of hydrogen fluoride, and the stripping temperature of the stripping method is high, which will strip part of the water in the solution, resulting in the solution concentration being supersaturated, and the solubility of manganese sulfate drops sharply after the temperature is higher than 105°C and other factors, which leads to the crystallization of manganese sulfate, hindering the smooth progress of the entire defluorination process, making the traditional stripping method not applicable to the defluorination of manganese sulfate solution. This is also the reason why there is no report on the defluorination of manganese sulfate solution using the stripping method at present. Summary of the Invention

[0009] The purpose of the present invention is to provide a high-purity manganese sulfate defluorination method and defluorination system for impurity removal by fluorination method. The present invention first applies the stripping method to the defluorination of manganese sulfate solution. Through the method of the present invention, the fluorine in the manganese sulfate solution can be removed, and there will be no phenomenon of supersaturation of the manganese sulfate solution and crystallization due to the decrease in solubility. It has the characteristics of simple process, low treatment cost, high defluorination purity, and no introduction of new impurities; while the system of the present invention has the characteristics of reasonable design, energy saving and consumption reduction.

[0010] The technical solution of the present invention: A high-purity manganese sulfate defluorination method for impurity removal by fluorination method uses a high-purity manganese sulfate solution for impurity removal by fluorination method as the raw material, concentrated sulfuric acid as the reaction agent, and high-temperature steam as the stripping gas. After stripping in a stripping tower, the defluorination of high-purity manganese sulfate for impurity removal by fluorination method is completed; wherein, the inside of the stripping tower is in a vacuum environment.

[0011] In a preferred embodiment, for the above-mentioned high-purity manganese sulfate defluorination method for impurity removal by fluorination method, the specific steps of the method are as follows:

[0012] (1) Prepare a high-purity manganese sulfate solution for impurity removal by fluorination method, concentrated sulfuric acid, and high-temperature steam respectively;

[0013] (2) Use a vacuum pumping device to evacuate the inside of the stripping tower;

[0014] (3) Output and mix the high-purity manganese sulfate solution for impurity removal by fluorination method and concentrated sulfuric acid at the same time, and send the mixed solution to the top inside the stripping tower. The mixed solution falls from top to bottom inside the stripping tower under the action of its own gravity; at the same time, high-temperature steam is blown in from the bottom of the stripping tower. The high-temperature steam blows out and discharges the fluorine-containing gas in the falling mixed solution, and the falling liquid is the defluorinated high-purity manganese sulfate solution, realizing the defluorination of the high-purity manganese sulfate solution for impurity removal by fluorination method.

[0015] In a preferred embodiment, for the method for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, the fluorine-containing gas is discharged from the top of the stripping tower after stripping, and is recovered after being condensed by a condensation system.

[0016] In a preferred embodiment, for the method for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, the high-purity manganese sulfate solution after fluorine removal is first fed into a preheater to preheat the raw material of the high-purity manganese sulfate solution for fluorination method for impurity removal.

[0017] A system for removing fluorine from high-purity manganese sulfate by fluorination method for impurity removal includes a raw material storage tank for manganese sulfate solution, a concentrated sulfuric acid storage tank, a stripping tower, a steam distribution cylinder, a storage tank for manganese sulfate solution after fluorine removal, a gas condenser, a hydrofluoric acid storage tank and a vacuum unit;

[0018] The raw material storage tank for manganese sulfate solution and the concentrated sulfuric acid storage tank are connected in parallel and then connected to the liquid inlet of the stripping tower;

[0019] The steam distribution cylinder is connected to the gas inlet of the stripping tower;

[0020] The storage tank for manganese sulfate solution after fluorine removal is connected to the liquid outlet of the stripping tower;

[0021] The vacuum unit and the gas condenser are connected in series and then connected to the exhaust port of the stripping tower;

[0022] The hydrofluoric acid storage tank is connected to the liquid outlet of the gas condenser.

[0023] In a preferred embodiment, for the system for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, the raw material storage tank for manganese sulfate solution is first connected in series with a manganese sulfate solution preheater and then connected in parallel with the concentrated sulfuric acid storage tank; the manganese sulfate solution preheater is a heat exchange type preheater, and the inlet and outlet of its high-temperature solution channel are respectively connected to the liquid outlet of the stripping tower and the liquid inlet of the storage tank for manganese sulfate solution after fluorine removal.

[0024] In a preferred embodiment, for the system for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, a manganese sulfate solution cooling tower is further provided between the storage tank for manganese sulfate solution after fluorine removal and the stripping tower, or between the storage tank for manganese sulfate solution after fluorine removal and the manganese sulfate solution preheater.

[0025] In a preferred embodiment, for the system for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, the stripping tower is composed of a first-stage packed stripping tower, a second-stage packed stripping tower and a bubble cap tower connected in series from top to bottom; a reboiler is connected in parallel between the bottom and the upper part of the bubble cap tower through an external pipeline.

[0026] In a preferred embodiment, for the system for removing fluorine from high-purity manganese sulfate by the above-mentioned fluorination method for impurity removal, the liquid outlet of the gas condenser is connected to the liquid inlet of the stripping tower; the gas condenser is composed of a first-stage condenser and a second-stage condenser connected in series.

[0027] In a preferred embodiment, for the high-purity manganese sulfate defluorination system using the fluorination method for impurity removal, the gas outlet end of the vacuum unit is connected to a tail gas treatment tank.

[0028] Advantages of the present invention

[0029] 1. In the present invention, by using concentrated sulfuric acid as a reactant, fluoride ions in the manganese sulfate solution are converted into hydrogen fluoride, and then hydrogen fluoride is stripped by the stripping method, thereby achieving the purpose of defluorination of the manganese sulfate solution using the fluorination method for impurity removal.

[0030] 2. The present invention uses the stripping method for defluorination, which has the advantages of simple process, low treatment cost, high defluorination purity, and no introduction of new impurities. Through experimental verification, the treatment cost of the method of the present invention is only about 1 / 3 of the cost of the traditional extraction method.

[0031] 3. The present invention performs stripping in a vacuum environment and uses steam as the stripping gas. On the one hand, the vacuum environment will reduce the temperature of the stripping gas, avoiding the phenomenon that the solubility of manganese sulfate drops sharply and crystallizes at high temperatures. At the same time, while the steam is stripping, it will also supplement part of the water into the manganese sulfate solution, thereby making up for the water lost due to stripping and avoiding the crystallization of the manganese sulfate solution due to supersaturation. That is to say, through the process of the present invention, while achieving the purpose of defluorination of the manganese sulfate solution, it can also ensure the smooth progress of the defluorination process, which is suitable for industrial promotion.

[0032] 4. In the present invention, by using sulfuric acid as a reactant, it can react with manganese fluoride in the raw material of the manganese sulfate solution to generate manganese sulfate, thereby further increasing the concentration of manganese sulfate. Under the conditions of high-temperature steam water replenishment and vacuum cooling, it can also avoid the supersaturation crystallization of manganese sulfate and ensure the smooth progress of the defluorination process.

[0033] 5. The system of the present invention is reasonably designed, and after recovering the preheat, it has the advantages of energy conservation and emission reduction.

[0034] 6. In the present invention, by connecting the drain outlet of the gas condenser to the stripping tower, and at the same time, a reboiler is arranged outside the stripping tower, the concentration and purity of the separated hydrogen fluoride and manganese sulfate solution are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Attached Figure 1 is a schematic structural diagram of the defluorination system of the present invention;

[0036] Attached Figure 2 is a schematic structural diagram of the stripping tower of the present invention;

[0037] Attached Figure 3 is a schematic structural diagram of the gas condenser of the present invention.

[0038] Description of the attached drawing reference numerals: 1 - raw material storage tank for manganese sulfate solution, 2 - concentrated sulfuric acid storage tank, 3 - stripping tower, 31 - primary packed stripping tower, 32 - secondary packed stripping tower, 33 - bubble cap tower, 4 - storage tank for manganese sulfate solution after defluorination, 5 - gas condenser, 51 - primary condenser, 52 - secondary condenser, 6 - hydrofluoric acid storage tank, 7 - vacuum unit, 8 - steam separator, 9 - preheater for manganese sulfate solution, 10 - cooling tower for manganese sulfate solution, 11 - reboiler, 12 - tail gas treatment tank. Detailed implementation mode

[0039] The present invention will be further described below in conjunction with embodiments, but it shall not be used as a basis for limiting the present invention.

[0040] Embodiment of the present invention

[0041] Embodiment 1:

[0042] A method for defluorinating high-purity manganese sulfate by fluorination method for impurity removal, the specific steps are as follows:

[0043] (1) Prepare high-purity manganese sulfate solution for impurity removal by fluorination method, concentrated sulfuric acid and high-temperature steam respectively;

[0044] (2) Use a vacuum device to evacuate the stripping tower, and the vacuum degree is -0.053 to -0.042 MPa;

[0045] (3) Output and mix the high-purity manganese sulfate solution for impurity removal by fluorination method and concentrated sulfuric acid at the same time, and send the mixed solution to the top inside the stripping tower. The mixed solution falls from top to bottom inside the stripping tower under the action of its own gravity; at the same time, high-temperature steam is blown into the bottom of the stripping tower. The high-temperature steam blows off and discharges the fluorine-containing gas in the falling mixed solution, and the falling liquid is the high-purity manganese sulfate solution after defluorination, realizing the defluorination of the high-purity manganese sulfate solution for impurity removal by fluorination method.

[0046] In a preferred embodiment, the fluorine-containing gas is discharged from the top of the stripping tower after being blown off and recovered for fluorine after being condensed by a condensation system.

[0047] In a preferred embodiment, the high-purity manganese sulfate solution after defluorination is first sent to a preheater for preheating the raw material of the high-purity manganese sulfate solution for impurity removal by fluorination method.

[0048] Embodiment 2:

[0049] A defluorination system for high-purity manganese sulfate by fluorination method for impurity removal, as shown in the attached Figures 1 - 3 drawing, includes a raw material storage tank 1 for manganese sulfate solution, a concentrated sulfuric acid storage tank 2, a stripping tower 3, a steam separator 8, a storage tank 4 for manganese sulfate solution after defluorination, a gas condenser 5, a hydrofluoric acid storage tank 6 and a vacuum unit 7;

[0050] The raw material storage tank 1 of the manganese sulfate solution and the concentrated sulfuric acid storage tank 2 are connected in parallel and then connected to the liquid inlet of the stripping tower 3;

[0051] The steam header 8 is connected to the air inlet of the stripping tower 3;

[0052] The storage tank 4 of the manganese sulfate solution after defluorination is connected to the liquid outlet of the stripping tower 3;

[0053] The vacuum unit 7 and the gas condenser 5 are connected in series and then connected to the exhaust port of the stripping tower 3;

[0054] The hydrofluoric acid storage tank 6 is connected to the liquid outlet of the gas condenser 5.

[0055] When carrying out the specific defluorination process, first inject the raw material of the manganese sulfate solution and concentrated sulfuric acid into the raw material storage tank 1 of the manganese sulfate solution and the concentrated sulfuric acid storage tank 2 respectively, inject high-temperature steam into the steam header 8, and start the vacuum unit 7 to evacuate the whole system. After the preparatory work is done, open the valves on the discharge pipes of the raw material storage tank 1 of the manganese sulfate solution and the concentrated sulfuric acid storage tank 2 simultaneously. The raw material of the manganese sulfate solution and the concentrated sulfuric acid converge and mix. Manganese fluoride and sulfuric acid in them react to form manganese sulfate and hydrogen fluoride. The mixed liquid finally enters the top inside the stripping tower 3 under the action of negative pressure and drifts down under its own action. At the same time, open the valve at the exhaust port of the steam header 8, and the high-temperature steam is blown into the stripping tower 3 from the bottom and flows upward, contacting the falling mixed liquid, so as to strip the hydrogen fluoride gas in the mixed liquid and complete the separation of hydrogen fluoride. The stripped hydrogen fluoride gas and steam are discharged from the top of the stripping tower 3 and enter the gas condenser 5. After condensation, a hydrofluoric acid solution is formed and recovered into the hydrofluoric acid storage tank 6, while the falling manganese sulfate solution after defluorination is sent to the storage tank 4 of the manganese sulfate solution after defluorination through the liquid outlet of the stripping tower 3 for storage.

[0056] In the preferred embodiment, as shown in the appendix Figures 1 - 3 The raw material storage tank 1 of the manganese sulfate solution is first connected in series with the manganese sulfate solution preheater 9 and then connected in parallel with the concentrated sulfuric acid storage tank 2; the raw material of the manganese sulfate solution can be preheated by the manganese sulfate solution preheater 9 and then mixed with the concentrated sulfuric acid solution to accelerate the reaction rate.

[0057] In the preferred embodiment, as shown in the appendix Figures 1 - 3 The manganese sulfate solution preheater 9 is a heat exchange type preheater, and the inlet and outlet of its high-temperature solution channel are respectively connected to the liquid outlet of the stripping tower 3 and the liquid inlet of the storage tank 4 of the manganese sulfate solution after defluorination. The raw material of the manganese sulfate solution is preheated by heat exchange with the high-temperature manganese sulfate solution discharged from the stripping tower 3, realizing the recovery of partial preheating, which meets the requirements of energy conservation and emission reduction.

[0058] In the preferred embodiment, as shown in the appendix Figures 1 - 3As shown, a manganese sulfate solution cooling tower 10 is further provided between the de-fluorinated manganese sulfate solution storage tank 4 and the stripping tower 3, or between the de-fluorinated manganese sulfate solution storage tank 4 and the manganese sulfate solution preheater 9. Cooling the manganese sulfate solution in the manganese sulfate solution cooling tower 10 before storage can reduce the temperature of the stored liquid, reduce the evaporation of water in the manganese sulfate solution, avoid crystallization, and ensure safe production.

[0059] In a preferred embodiment, as shown in the attached Figures 1 - 3 figure, the stripping tower 3 is composed of a first-stage packed stripping tower 31, a second-stage packed stripping tower 32, and a bubble-cap tower 33 connected in series from top to bottom. The first-stage packed stripping tower 31, the second-stage packed stripping tower 32, and the bubble-cap tower 33 are connected in a bamboo joint manner. The upper first-stage packed stripping tower 31 and second-stage packed stripping tower 32 have low costs and strong stripping flexibility, while the lower bubble-cap tower 33 has good stripping effect. The combination of the two can reduce the cost of the entire equipment and also has strong flexibility in use.

[0060] In a preferred embodiment, as shown in the attached Figures 1 - 3 figure, a reboiler 11 is connected in parallel between the bottom and the upper part of the bubble-cap tower 33 through an external pipeline, and the temperature in the reboiler 11 is 80 - 85 °C. During the stripping process, the manganese sulfate solution flowing into the bottom of the stripping tower 3 first passes through the reboiler 11 for repeated heating and is repeatedly stripped by the bubble-cap tower 33, which can improve the stripping effect, thereby reducing the fluorine concentration in the manganese sulfate solution and further improving the purity of the manganese sulfate solution.

[0061] In a preferred embodiment, as shown in the attached Figures 1 - 3 figure, the liquid discharge port of the gas condenser 5 is connected to the liquid inlet of the stripping tower 3. In the initial stage of system startup, the concentration of the stripped hydrofluoric acid solution is low and the water content is large. At this time, close the valve of the inlet pipeline of the hydrofluoric acid storage tank 6 to force the hydrofluoric acid solution to flow back into the stripping tower 3 for reflux. This can not only avoid the loss of a large amount of water in the manganese sulfate solution, but also increase the concentration of the discharged hydrofluoric acid. When the startup is stable, then open the valve of the inlet pipeline of the hydrofluoric acid storage tank 6 to recover the high-concentration hydrofluoric acid.

[0062] In a preferred embodiment, as shown in the attached Figures 1 - 3 figure, the gas condenser 5 is composed of a first-stage condenser 51 and a second-stage condenser 52 connected in series. The series connection of the two groups can improve the condensation effect, increase the fluorine recovery rate, and reduce the fluorine content in the discharged gas.

[0063] In a preferred embodiment, as shown in the attached Figures 1 - 3 figure, the gas outlet end of the vacuum unit 7 is connected to a tail gas treatment tank 12. The tail gas treatment tank 12 is filled with hydrofluoric acid absorption packing, such as calcium hydroxide, which is mainly used for purifying the tail gas.

[0064] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for removing fluorine from high-purity manganese sulfate by fluorination for impurity removal, characterized in that: Using a high-purity manganese sulfate solution purified by the fluorination method as the raw material, concentrated sulfuric acid as the reaction agent, and high-temperature steam as the stripping gas, the fluorine in the high-purity manganese sulfate purified by the fluorination method is removed after stripping in a stripping tower; wherein, the inside of the stripping tower is in a vacuum environment; The specific steps of the method are as follows: (1) Prepare a high-purity manganese sulfate solution purified by the fluorination method, concentrated sulfuric acid, and high-temperature steam respectively; (2) Use a vacuum pumping device to evacuate the inside of the stripping tower; (3) Simultaneously output and mix the high-purity manganese sulfate solution purified by the fluorination method and concentrated sulfuric acid, and send the mixed solution to the top end inside the stripping tower. The mixed solution falls from top to bottom inside the stripping tower under the action of its own gravity; at the same time, high-temperature steam is blown into the bottom of the stripping tower. The high-temperature steam strips and discharges the fluorine-containing gas in the falling mixed solution, and the falling liquid is the high-purity manganese sulfate solution after defluorination, realizing the defluorination of the high-purity manganese sulfate solution purified by the fluorination method.

2. The high-purity manganese sulfate defluorination method by fluorination for impurity removal according to claim 1, characterized in that: The fluorine-containing gas is discharged from the top of the stripping tower after stripping and recovered for fluorine after being condensed by a condensation system.

3. The high-purity manganese sulfate defluorination method by fluorination for impurity removal according to claim 1, wherein: The high-purity manganese sulfate solution after defluorination is first sent to a preheater to preheat the raw material of the high-purity manganese sulfate solution purified by the fluorination method.

4. A high-purity manganese sulfate defluorination system for impurity removal by fluorination method, characterized in that: It includes a manganese sulfate solution raw material storage tank (1), a concentrated sulfuric acid storage tank (2), a stripping tower (3), a steam distribution cylinder (8), a manganese sulfate solution storage tank (4) after defluorination, a gas condenser (5), a hydrofluoric acid storage tank (6), and a vacuum unit (7); The manganese sulfate solution raw material storage tank (1) and the concentrated sulfuric acid storage tank (2) are connected in parallel and then connected to the liquid inlet of the stripping tower (3); The steam distribution cylinder (8) is connected to the gas inlet of the stripping tower (3); The manganese sulfate solution storage tank (4) after defluorination is connected to the liquid outlet of the stripping tower (3); The vacuum unit (7) and the gas condenser (5) are connected in series and then connected to the exhaust port of the stripping tower (3); The hydrofluoric acid storage tank (6) is connected to the liquid outlet of the gas condenser (5); The manganese sulfate solution raw material storage tank (1) is first connected in series with a manganese sulfate solution preheater (9) and then connected in parallel with the concentrated sulfuric acid storage tank (2); the manganese sulfate solution preheater (9) is a heat exchange type preheater, and the inlet and outlet of its high-temperature solution channel are respectively connected to the liquid outlet of the stripping tower (3) and the liquid inlet of the manganese sulfate solution storage tank (4) after defluorination; The stripping tower (3) is composed of a first-stage packed stripping tower (31), a second-stage packed stripping tower (32), and a bubble-cap tower (33) connected in series from top to bottom; a reboiler (11) is connected in parallel between the bottom and the upper part of the bubble-cap tower (33) through an external pipeline.

5. The high-purity manganese sulfate defluorination system for impurity removal by fluorination method according to claim 4, wherein: A manganese sulfate solution cooling tower (10) is also provided between the manganese sulfate solution storage tank (4) after defluorination and the stripping tower (3), or between the manganese sulfate solution storage tank (4) after defluorination and the manganese sulfate solution preheater (9).

6. The high-purity manganese sulfate defluorination system for impurity removal by fluorination method according to claim 4, wherein: The liquid outlet of the gas condenser (5) is connected to the liquid inlet of the stripping tower (3); the gas condenser (5) is composed of a first-stage condenser (51) and a second-stage condenser (52) connected in series.

7. The high-purity manganese sulfate defluorination system for impurity removal by fluorination method according to claim 4, wherein: The gas outlet end of the vacuum unit (7) is connected to a tail gas treatment tank (12).

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