Method for treating electrolytic manganese anode slime to recover manganese by using ammonium sulfate composite flux

Abstract

The invention discloses a method for treating electrolytic manganese anode slime to recover manganese by using an ammonium sulfate composite flux, which comprises the following steps: (1) drying, crushing, dry-grinding and screening manganese anode slime to obtain an electrolytic manganese anode slime sample; (2) uniformly mixing the electrolytic manganese anode slime sample with an ammonium sulfate composite flux, paving the mixture in a crucible, putting the crucible in the middle of a quartz tube in a tubular furnace, introducing inert gas to expel air, supplying gas in the whole process to perform roasting protection, starting a power supply, raising the temperature in the furnace to 150 DEG C, then starting constant-temperature roasting, raising the temperature in the furnace to 320 DEG C, performing constant-temperature roasting, and cooling to room temperature; raising the temperature in the furnace to 550 DEG C, roasting at constant temperature, naturally cooling to room temperature after roasting, carefully taking out a roasting slag sample, adding deionized water, leaching manganese sulfate at room temperature, and filtering and separating to obtain a manganese sulfate crude solution and leaching slag. The roasting temperature and the roasting time are greatly reduced, manganese is rapidly extracted and leached from the electrolytic manganese anode slime, and the cost is lower.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of comprehensive utilization of solid waste resources, and particularly relates to a method for recovering manganese from electrolytic manganese anode slime by using ammonium sulfate composite flux. BACKGROUND

[0002] The electrolytic manganese anode slime is a by-product rich in manganese and lead generated in the production process of electrolytic manganese, and its treatment and resource utilization has been the focus of the industry. The manganese content of the electrolytic manganese anode slime is relatively high, usually 20% to 50%, mainly in the form of MnO2 (manganese dioxide), and part of Mn3O4 (manganese trioxide) or low-valence manganese oxide (such as MnO); at the same time, the lead content is about 10% to 30%, mainly from associated lead in manganese ore or corrosion of anode plate (lead alloy) in the electrolysis process, in the form of PbO2 (lead dioxide), PbSO4 (lead sulfate) or PbO (lead oxide); it also contains 1% to 10% of iron and other trace metals such as tin, copper and nickel. Industrially, it is generally used as a soft manganese ore raw material to produce manganese sulfate by using iron powder reduction, ferrous sulfate reduction leaching, two ore roasting and water leaching, or two ore one-step method. However, no matter which method is used, the high-valence state of manganese in the electrolytic manganese anode slime is stable, the reduction efficiency is low, which leads to low manganese recovery rate, and the synchronous dissolution of lead and the difficulty of separation are large, and the purification process conditions are harsh, which leads to the difficulty of leaching liquid purification, and the treatment of electrolytic manganese anode slime by landfill not only wastes resources, but also easily pollutes the environment. SUMMARY

[0003] In order to solve the above technical problems, the present application provides a method for recovering manganese from electrolytic manganese anode slime by using ammonium sulfate composite flux. The roasting temperature and time are greatly reduced, and the manganese is quickly extracted and leached from the electrolytic manganese anode slime, and the cost is lower.

[0004] In order to achieve the above purpose, the present application provides the following technical scheme: a method for recovering manganese from electrolytic manganese anode slime by using ammonium sulfate composite flux, characterized in that the recovery is carried out according to the following steps:

[0005] (1) The manganese anode slime is dried, crushed, dry ground and sieved to obtain an electrolytic manganese anode slime sample;

[0006] (2) the electrolytic manganese anode slime sample is mixed with the ammonium sulfate composite flux uniformly, is laid in the middle part of the quartz tube of the tube furnace in the crucible, inert gas is introduced to drive away air and supply gas throughout the process to carry out roasting protection, the power is started, the temperature in the furnace is increased to 150℃ at a temperature increasing speed of 10-15℃ / min, then constant temperature roasting is started for 5-10 min, the temperature in the furnace is increased to 320℃ at a temperature increasing speed of 10-15℃ / min, constant temperature roasting is carried out for 5-10 min, the temperature in the furnace is increased to 550℃ at a temperature increasing speed of 20-25℃ / min, constant temperature roasting is carried out for 15-20 min, after roasting is completed, the roasting slag sample is taken out, deionized water is added to leach manganese sulfate at room temperature, filtration separation is carried out, and manganese sulfate crude liquid and leaching residue are obtained; the mixing mass ratio of the electrolytic manganese anode slime sample and the ammonium sulfate composite flux is 1.5-2.5:1; the ammonium sulfate composite flux is mixed by 88%-92% ammonium sulfate and 8%-12% urea;

[0007] (3) manganese powder is added into the manganese sulfate crude liquid to react at room temperature, filtration is carried out; ammonium sulfide is added into the filtrate to react at room temperature, filtration is carried out, a flocculating agent is added into the filtrate to precipitate and filter; ammonia water is added into the filtrate to adjust the pH value to 6-7, citric acid is added to react at room temperature, and filtration separation is carried out to obtain purified liquid;

[0008] (4) ammonium bicarbonate is added into the purified liquid to react at 40-60℃, filtration is carried out to obtain manganese carbonate and ammonium sulfate solution, and the ammonium sulfate solution is evaporated for recycling.

[0009] In the above scheme: the manganese carbonate is washed with deionized water for 3-5 times, is calcined at high temperature of 830-1000℃ to obtain solid trimanganese tetroxide, and after being crushed or sand ground, the solid trimanganese tetroxide is washed with deionized water and is dried to obtain battery-grade trimanganese tetroxide.

[0010] In the above scheme: the electrolytic manganese anode slime is dried at 100-110℃.

[0011] In the above scheme: the electrolytic manganese anode slime is crushed to have a particle size of ≤80μm and is sieved through a 200-mesh sieve.

[0012] In the above scheme: the inert gas is nitrogen, and the flow rate is 2.0-3.0L / min.

[0013] In the above scheme: during leaching, the addition amount of deionized water is 8-12 times the mass of the electrolytic manganese anode slime, and the leaching time is 50-70 min.

[0014] In the above scheme: the addition amount of the manganese powder is 2‰-3‰ of the electrolytic manganese anode slime; and the addition amount of the ammonium sulfide is 1‰-2‰ of the mass of the electrolytic manganese anode slime.

[0015] In the scheme, the flocculant is polyacrylamide, and the adding amount is 1‰-2‰ of the mass of the electrolytic manganese anode slime.

[0016] In the scheme, the adding amount of citric acid is 1.5‰-2‰.

[0017] Manganese in the electrolytic manganese anode slime mainly exists in the form of MnO2, and under the condition of no inert gas protection, due to the action of oxygen in the air, the MnO2 cannot be completely sulfated into MnSO4 by using single ammonium sulfate as flux, and no matter whether acid leaching or alkali leaching is used, the leaching rate of manganese is low due to the large amount of MnO2, so the amount of ammonium sulfate is usually increased, a large amount of ammonia gas is generated by decomposition of ammonium sulfate to isolate the oxidation of oxygen in the air, and the sulfation process of MnO2 is strengthened, but the effect is still limited, even if a composite flux of ammonium sulfate (adding a reducing agent) is used, the amount of the composite flux still needs to be increased to make up for ammonium sulfate, and the atmosphere generated by the reducing agent is also needed to prevent the oxidation of oxygen in the air. In the present application, the roasting is protected by inert gas, and the amount of consumed ammonium sulfate is significantly reduced due to the absence of interference from oxygen in the air, the utilization rate of sulfation is nearly 100%, and the sulfation purpose can be achieved in a very short roasting time. By adding a small amount of urea to ammonium sulfate, the formation of the low eutectic point of urea and ammonium sulfate not only reduces the flow temperature of the composite flux, but also accelerates the heat transfer in the mixed sample due to the early formation of a large amount of gas (ammonia and carbon dioxide), thereby further improving the utilization efficiency of heat, and a large amount of reducing ammonia gas can reduce high-valence manganese in the electrolytic manganese anode slime into low-valence manganese, promote the generation of manganese sulfate, and accelerate the reaction process of the generation of manganese sulfate. In order to remove impurities iron in the roasting process, the final roasting temperature is increased to 550℃, at this high temperature, manganese sulfate does not decompose, and iron sulfate is decomposed into iron oxide in a short time, and part of other metal impurities sulfates are also partially decomposed. In the sulfation process, impurities lead, calcium and barium form insoluble sulfates, thereby achieving the removal of main metal impurities in the roasting process.

[0018] In the subsequent wet impurity removal process, manganese powder is added to the manganese sulfate crude solution, and trace amounts of metal ions such as lead, iron, cobalt, nickel, copper and zinc remaining in the manganese sulfate crude solution are reduced into metal ions, which are separated by filtration; ammonium sulfide is added to the filtrate to further remove the residual trace amounts of metal ions; polyacrylamide is added to the filtrate to remove residual aluminum and silicon; and citric acid is added to the filtrate to make the residual magnesium ions in the solution complex with the citric acid, and then the magnesium ions are removed in the subsequent ammonium bicarbonate precipitation process.

[0019] Advantages:

[0020] (1) By using the technical solution, the roasting temperature and time are greatly reduced, and manganese is quickly extracted and leached from the electrolytic manganese anode slime, and the cost is lower.

[0021] (2) Adopting the technical scheme, the recovery rate of extracting leaching manganese from electrolytic manganese anode slime is high and stable at more than 98%, which is much higher than the recovery rate of 85% of the existing ammonium sulfate roasting technology.

[0022] (3) Adopting the technical scheme, low-temperature roasting and water immersion and shortening of the process flow realize the dual goals of energy saving at the source and emission reduction, which is the key path to promote the green and low-carbon transformation of industry.

[0023] (4) Adopting the technical scheme, a large amount of impurities are removed in the roasting process, which reduces the pressure of subsequent wet method impurity removal, and the obtained high-purity trimanganese tetraoxide can meet the requirements of high-end applications. DETAILED DESCRIPTION

[0024] The application will be further described below in combination with examples.

[0025] Example 1

[0026] The electrolytic manganese anode slime containing 28.5% manganese was dried at 100-110°C, crushed to a particle size of ≤80 μm, dry ground and sieved (sieved through a 200 mesh sieve) to obtain an electrolytic manganese anode slime sample. 100 g of the electrolytic manganese anode slime sample was mixed with 40 g of an ammonium sulfate complex flux. The ammonium sulfate complex flux was obtained by mixing 92% ammonium sulfate and 8% urea. The mixture was laid flat in a square corundum crucible, placed in the middle of a quartz tube of a tube furnace, nitrogen was introduced to remove air and then supplied throughout the roasting protection, the inert gas was nitrogen, the flow rate was 2.0-3.0 L / min, the power was started, the temperature in the furnace was increased to 150°C at a rate of 15°C / min, then constant temperature roasting was started for 8 min, the temperature in the furnace was increased to 320°C at a rate of 10°C / min, constant temperature roasting was continued for 10 min, the temperature in the furnace was increased to 550°C at a rate of 25°C / min, constant temperature roasting was continued for 15 min, after roasting was completed, the roasting slag sample was naturally cooled to room temperature, 1000 g of deionized water was added at room temperature and leached for 60 min, filtered and separated to obtain a crude manganese sulfate solution and a leaching residue. 0.2 g of metallic manganese powder was added to the crude manganese sulfate solution, reacted at room temperature for 30 min, filtered and separated, 0.1 g of ammonium sulfide was added to the filtrate, reacted at room temperature for 15 min, filtered and separated, 0.2 g of polyacrylamide was added to the filtrate, reacted for 30 min, precipitated, filtered and separated, then ammonia water was added to adjust the pH value to 6.8, 0.2 g of citric acid was added, reacted at room temperature for 15 min, filtered and separated, 60 g of ammonium bicarbonate was added to the filtrate to obtain manganese carbonate and ammonium sulfate solution, the ammonium sulfate solution was evaporated to recover ammonium sulfate. The manganese carbonate was washed with deionized water for 3 times, calcined at a high temperature of 920°C to obtain solid trimanganese tetroxide, the solid trimanganese tetroxide was crushed or sand ground, washed with deionized water, dried to obtain high purity trimanganese tetroxide, the manganese recovery rate in the manganese anode slime was 98.78%, and the purity of the trimanganese tetroxide was 99.85%.

[0027] Example 2

[0028] The electrolytic manganese anode slime containing 31.1% manganese was dried at 100-110°C, crushed to a particle size of ≤80 μm, dry ground and sieved (sieved through a 200 mesh sieve) to obtain an electrolytic manganese anode slime sample. 100 g of the electrolytic manganese anode slime sample was mixed uniformly with 50 g of an ammonium sulfate complex flux, which was prepared by mixing 88% ammonium sulfate and 12% urea. The mixture was laid flat in a square corundum crucible, placed in the middle of a quartz tube of a tube furnace, nitrogen was introduced to remove air and then supplied throughout the process to perform roasting protection, the inert gas was nitrogen, the flow rate was 2.0-3.0 L / min, the power was started, the temperature in the furnace was increased to 150°C at a rate of 10°C / min, then constant temperature roasting was started for 10 min, the temperature in the furnace was increased to 320°C at a rate of 10°C / min, constant temperature roasting was performed for 6 min, the temperature in the furnace was increased to 550°C at a rate of 20°C / min, constant temperature roasting was performed for 18 min, after roasting was completed, the roasting slag sample was naturally cooled to room temperature, 1200 g of deionized water was added at room temperature and leaching was performed for 70 min, filtration was performed to separate the leaching slag and a crude manganese sulfate solution was obtained. 0.25 g of metallic manganese powder was added to the crude manganese sulfate solution, reaction was performed at room temperature for 30 min, filtration was performed to separate the solution, 0.16 g of ammonium sulfide was added to the filtrate, reaction was performed at room temperature for 15 min, filtration was performed to separate the solution, 0.18 g of polyacrylamide was added to the filtrate, reaction was performed for 30 min, precipitation and filtration were performed, the pH value was adjusted to 6.6 using ammonia water, 0.15 g of citric acid was added, reaction was performed at room temperature for 15 min, filtration was performed to separate the solution, 65 g of ammonium bicarbonate was added to the filtrate to obtain manganese carbonate and an ammonium sulfate solution, the ammonium sulfate solution was evaporated to recover ammonium sulfate. The manganese carbonate was washed with deionized water for 5 times, calcined at a high temperature of 920°C to obtain solid trimanganese tetroxide, the solid trimanganese tetroxide was crushed or sand ground, washed with deionized water, dried to obtain high purity trimanganese tetroxide, the manganese recovery rate of the manganese anode slime was 98.56%, and the purity of the trimanganese tetroxide was 99.81%.

[0029] Example 3

[0030] The electrolytic manganese anode slime containing 40.3% manganese was dried at 100-110°C, crushed to a particle size of ≤80 μm, dry ground and sieved (sieved through a 200 mesh sieve) to obtain an electrolytic manganese anode slime sample. 100 g of the electrolytic manganese anode slime sample was mixed uniformly with 66 g of an ammonium sulfate complex flux, which was prepared by mixing 90% ammonium sulfate and 10% urea. The mixture was laid flat in a square corundum crucible, placed in the middle of a quartz tube of a tube furnace, nitrogen gas was introduced to remove air and then supplied throughout the process to perform roasting protection, the inert gas was nitrogen, the flow rate was 2.0-3.0 L / min, the power supply was started, the temperature in the furnace was increased to 150°C at a rate of 12°C / min, then constant temperature roasting was started for 5 min, the temperature in the furnace was increased to 320°C at a rate of 10°C / min, constant temperature roasting was performed for 5 min, the temperature in the furnace was increased to 550°C at a rate of 25°C / min, constant temperature roasting was performed for 15 min, after roasting was completed, the roasting slag sample was naturally cooled to room temperature, 800 g of deionized water was added to the roasting slag sample at room temperature and leached for 70 min, filtration separation was performed, and a crude manganese sulfate solution and a leaching residue were obtained. 0.3 g of metallic manganese powder was added to the crude manganese sulfate solution, reaction was performed at room temperature for 30 min, filtration separation was performed, 0.2 g of ammonium sulfide was added to the filtrate, reaction was performed at room temperature for 15 min, filtration separation was performed, 0.1 g of polyacrylamide was added to the filtrate, reaction was performed for 30 min, precipitation and filtration separation were performed, ammonia water was added to adjust the pH value to 6.3, 0.18 g of citric acid was added, reaction was performed at room temperature for 15 min, filtration separation was performed, 85 g of ammonium bicarbonate was added to the filtrate, and manganese carbonate and an ammonium sulfate solution were obtained, the ammonium sulfate solution was evaporated to recover ammonium sulfate. The manganese carbonate was washed with deionized water for 5 times, calcined at a high temperature of 920°C to obtain solid trimanganese tetroxide, the solid trimanganese tetroxide was crushed or sand ground, washed with deionized water, and dried to obtain high-purity trimanganese tetroxide, the manganese recovery rate in the manganese anode slime was 99.30%, and the purity of the trimanganese tetroxide was 99.87%.

[0031] Example 4

[0032] The electrolytic manganese anode slime containing 28.5% manganese was dried at 100-110°C, crushed to a particle size of 80 μm or less, dry ground, and sieved through a 200 mesh screen to obtain an electrolytic manganese anode slime sample. 100 g of the electrolytic manganese anode slime sample was mixed with 200 g of an ammonium sulfate complex flux. The ammonium sulfate complex flux was prepared by mixing 92% ammonium sulfate and 8% urea. The mixture was spread on a square-shaped corundum crucible and placed in the middle of a quartz tube of a tube furnace. The temperature in the furnace was raised to 150°C at a rate of 15°C / min, and then constant temperature roasting was started for 8 min. The temperature in the furnace was raised to 320°C at a rate of 10°C / min, and then constant temperature roasting was started for 10 min. The temperature in the furnace was raised to 550°C at a rate of 25°C / min, and then constant temperature roasting was started for 15 min. After the roasting was completed, the sample was naturally cooled to room temperature, and then carefully removed. 1000 g of deionized water was added to the roasted residue sample at room temperature and leached for 60 min. The leached residue was separated by filtration to obtain a crude manganese sulfate solution and a leached residue. 0.2 g of metallic manganese powder was added to the crude manganese sulfate solution at room temperature and reacted for 30 min. The reaction mixture was separated by filtration, and then 0.1 g of ammonium sulfide was added to the filtrate at room temperature and reacted for 15 min. The reaction mixture was separated by filtration, and then 0.2 g of polyacrylamide was added to the filtrate at room temperature and reacted for 30 min. The reaction mixture was precipitated, separated by filtration, and then adjusted to a pH of 6.8 by adding ammonia water. 0.2 g of citric acid was added to the filtrate at room temperature and reacted for 15 min. The reaction mixture was separated by filtration, and then 60 g of ammonium bicarbonate was added to the filtrate to obtain manganese carbonate and an ammonium sulfate solution. The ammonium sulfate solution was evaporated to recover ammonium sulfate. The manganese carbonate was washed with deionized water three times, and then calcined at a high temperature of 920°C to obtain solid trimanganese tetraoxide. The solid trimanganese tetraoxide was ground or sand-milled, washed with deionized water, and dried to obtain high-purity trimanganese tetraoxide. The recovery rate of manganese from the manganese anode slime was 80.76%, and the purity of the trimanganese tetraoxide was 99.84%.

[0033] Example 5

[0034] The electrolytic manganese anode slime containing 31.1% manganese is dried at 100-110°C, crushed to a particle size of ≤80 μm, dry ground, and sieved through a 200-mesh screen to obtain an electrolytic manganese anode slime sample. 100 g of the electrolytic manganese anode slime sample is mixed with 50 g of an ammonium sulfate complex flux. The ammonium sulfate complex flux is obtained by mixing 92% ammonium sulfate and 8% urea. The mixture is spread on a square corundum crucible and placed in the middle of a quartz tube of a tube furnace. The temperature in the furnace is raised to 150°C at a rate of 15°C / min, and then constant temperature roasting is started for 8 min. The temperature in the furnace is raised to 320°C at a rate of 10°C / min, and then constant temperature roasting is started for 10 min. The temperature in the furnace is raised to 550°C at a rate of 25°C / min, and then constant temperature roasting is started for 15 min. After roasting is completed, the sample is naturally cooled to room temperature, and then carefully removed. 1000 g of deionized water is added to the roasted residue sample at room temperature, and leaching is carried out for 60 min. Filtration is performed to obtain a crude manganese sulfate solution and a leaching residue. 0.25 g of metallic manganese powder is added to the crude manganese sulfate solution at room temperature, and reaction is carried out for 30 min. Filtration is performed, and then 0.16 g of ammonium sulfide is added to the filtrate at room temperature, and reaction is carried out for 15 min. Filtration is performed, and then 0.2 g of polyacrylamide is added to the filtrate at room temperature, and reaction is carried out for 30 min. Precipitation and filtration are performed, and then ammonia water is added to adjust the pH value to 6.6. 0.15 g of citric acid is added to the filtrate at room temperature, and reaction is carried out for 15 min. Filtration is performed, and then 65 g of ammonium bicarbonate is added to the filtrate to obtain a manganese carbonate and ammonium sulfate solution. The ammonium sulfate solution is evaporated to recover ammonium sulfate. The manganese carbonate is washed with deionized water for 3 times, and then calcined at a high temperature of 920°C to obtain solid trimanganese tetroxide. The solid trimanganese tetroxide is crushed or sand ground, washed with deionized water, and dried to obtain high-purity trimanganese tetroxide. The manganese recovery rate of the manganese anode slime is 76.90%, and the purity of the trimanganese tetroxide is 99.72%.

[0035] The present application is not limited to the above-described embodiments, and those skilled in the art can understand that various changes, modifications, replacements, and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux, characterized in that, Follow these steps to recycle: (1) The manganese anode mud was dried, crushed, dry-ground and screened to obtain an electrolytic manganese anode mud sample; (2) Mix the electrolytic manganese anode mud sample with ammonium sulfate composite flux evenly, spread it in a crucible, place it in the middle of the quartz tube in a tube furnace, introduce inert gas to purge the air and supply gas throughout the roasting process for protection, start the power supply, raise the furnace temperature to 150℃ at a heating rate of 10-15℃ / min, then start constant temperature roasting for 5-10 min, continue to raise the furnace temperature to 320℃ at a heating rate of 10-15℃ / min, maintain constant temperature roasting for 5-10 min, and continue... The furnace temperature was raised to 550℃ at a heating rate of 20-25℃ / min, and calcined at a constant temperature for 15-20 minutes. After calcination, the sample was allowed to cool naturally to room temperature. The calcined residue sample was then removed, and deionized water was added to leach manganese sulfate at room temperature. The residue was filtered and separated to obtain crude manganese sulfate solution and leaching residue. The mass ratio of electrolytic manganese anode mud sample to ammonium sulfate composite flux was 1.5-2.5:

1. The ammonium sulfate composite flux was composed of 88%-92% ammonium sulfate and 8%-12% urea. (3) Add metallic manganese powder to the crude manganese sulfate solution, react at room temperature, and filter; add ammonium sulfide to the filtrate, react at room temperature, and filter; add flocculant to the filtrate, precipitate, and filter; add ammonia water to the filtrate to adjust the pH to 6-7, add citric acid to react at room temperature, and filter to separate and obtain purified solution. (4) Add ammonium bicarbonate to the purified liquid, react at 40-60℃, filter to obtain manganese carbonate and ammonium sulfate solution, and evaporate the ammonium sulfate solution for recycling.

2. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 1, characterized in that: Manganese carbonate is washed with deionized water 3 to 5 times and then calcined at a high temperature of 830 to 1000°C to obtain solid manganese tetroxide. After being crushed or sand-milled, the solid manganese tetroxide is washed with deionized water and dried to obtain battery-grade manganese tetroxide.

3. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 1 or 2, characterized in that: The electrolytic manganese anode mud is dried at 100–110°C.

4. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 3, characterized in that: The electrolytic manganese anode mud is crushed into particles with a diameter ≤80μm and sieved through a 200-mesh sieve.

5. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 4, characterized in that: The inert gas is nitrogen, and the flow rate is 2.0–3.0 L / min.

6. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 5, characterized in that: During leaching, the amount of deionized water added is 8 to 12 times the mass of the electrolytic manganese anode mud, and the leaching time is 50 to 70 minutes.

7. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 6, characterized in that: The amount of metallic manganese powder added is 2‰ to 3‰ of the electrolytic manganese anode mud; the amount of ammonium sulfide added is 1‰ to 2‰ of the mass of the electrolytic furnace manganese iron slag.

8. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 7, characterized in that: The flocculant is polyacrylamide, and the amount added is 1‰ to 2‰ of the mass of electrolytic manganese anode mud.

9. The method for recovering manganese from electrolytic manganese anode mud using ammonium sulfate composite flux according to claim 8, characterized in that: The amount of citric acid added is 1.5‰ to 2‰.