Method for recycling electrolytic manganese industry waste salt

Abstract

The application provides a method for recycling electrolytic manganese industry waste salt, comprising the following steps: mixing the electrolytic manganese industry waste salt with calcium oxide, then performing first heat treatment and second heat treatment to obtain a treatment product; performing water immersion and solid-liquid separation on the treatment product to obtain first leaching residue and first leaching solution; performing evaporation crystallization on the first leaching solution to obtain a magnesium sulfate product; mixing the first leaching residue with ammonium sulfate and performing ball milling to obtain a mixture; performing calcination on the mixture to obtain a calcination product; performing water immersion on the calcination product to obtain second leaching residue and second leaching solution; performing evaporation crystallization on the second leaching solution to obtain a manganese sulfate product; performing water washing, solid-liquid separation and drying on the second leaching residue to obtain industrial gypsum. The method has the advantages of simple process, mild process conditions, low energy consumption, low cost, elimination of environmental pressure of electrolytic manganese industry waste salt stockpiling, and efficient recovery of Mg, Mn, NH4 + / NH3 and S resources in the electrolytic manganese industry waste salt and recovery of Ca, and the purity of the recovered manganese sulfate reaches the battery grade.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of metallurgical solid waste treatment, and particularly relates to a method for treating and recycling industrial waste salt of electrolytic manganese by sub-section molten salt. BACKGROUND

[0002] As a traditional high-pollution industry, electrolytic manganese production generates a large amount of industrial waste salt of electrolytic manganese during the manufacturing process. According to statistics, 1-2 tons of waste salt are generated per ton of electrolytic manganese produced. More than 1 million tons of industrial waste salt of electrolytic manganese are generated in China every year. A large number of Mg and Ca-containing minerals are associated in the ore raw material for electrolytic manganese production. These minerals dissolve when leached with sulfuric acid, and the released Mg and Ca ions enter the leaching solution together with Mn ions. With the continuous circulation of the electrolytic manganese anode solution, Mg and Ca continuously enrich in the solution. When the Mg and Ca in the solution system reach a certain concentration, they will crystallize and precipitate in the standing settlement and electrolysis process of electrolytic manganese production due to the influence of temperature. The electrolytic manganese electrolyte mother liquor is an aqueous solution system of ammonium sulfate salt, and the concentration of ammonium sulfate is maintained at 90-120 g / L. Therefore, the crystallization and precipitation of Ca and Mg are accompanied by the precipitation of part of Mn, NH4 + Industrial waste salt of electrolytic manganese is a sulfate containing Mg, Mn, NH4 + / NH3, and Ca, and the main phases are ammonium magnesium hexahydrate, ammonium manganese hexahydrate, ammonium manganese sulfate, epsomite, and hemihydrate gypsum, with a small amount of sand.

[0003] At present, industrial waste salt of electrolytic manganese is mainly landfilled together with electrolytic manganese slag. This disposal method increases the amount of electrolytic manganese slag and the content of soluble salt in the electrolytic manganese slag, making it more difficult to be harmlessly treated. A large amount of soluble salt is washed into the leachate in the slag field with rainwater, increasing the amount of leachate and its salt concentration and increasing the risk of pollution to the surrounding soil and water. At the same time, industrial waste salt of electrolytic manganese can be used as an important secondary resource of Mg, Mn, NH4 + / NH3, Ca, and S, and has great recycling potential. SUMMARY

[0004] To solve the above technical problems, the application provides a method for recycling industrial waste salt of electrolytic manganese.

[0005] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0006] The application provides a method for recycling industrial waste salt of electrolytic manganese, comprising:

[0007] S1, mixing the industrial waste salt of electrolytic manganese with calcium oxide, first heating to a first temperature for first heat treatment, then heating to a second temperature for second heat treatment, to obtain a treatment product; the first temperature is lower than the second temperature; the second temperature is 500-700 DEG C;

[0008] S2, the treatment product is subjected to water immersion treatment and solid-liquid separation to obtain first leaching residue and first leaching liquor; the first leaching liquor is subjected to evaporation crystallization to obtain magnesium sulfate product;

[0009] S3, the first leaching residue is subjected to water washing and drying, and then mixed with ammonium sulfate and subjected to ball milling to obtain mixed material; the mixed material is subjected to calcination to obtain calcination product;

[0010] S4, the calcination product is subjected to water immersion, and then subjected to solid-liquid separation to obtain second leaching residue and second leaching liquor; the second leaching liquor is subjected to evaporation crystallization to obtain manganese sulfate product;

[0011] S5, the second leaching residue is subjected to water washing, and then subjected to solid-liquid separation and drying to obtain industrial gypsum.

[0012] Further, the calcium oxide and the electrolytic manganese industrial waste salt are determined according to the molar ratio CaO:(2NH4 + +Mn) = 1:1~1.5:1, preferably 1:1~1.3:1.

[0013] Further, in step S1, the first temperature is 300~500℃, preferably 400~500℃; the time of the first heat treatment is 20~180min, preferably 45~90min; the atmosphere of the first heat treatment is oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21~100%.

[0014] Further, in step S1, the second temperature is 600~700℃; the reaction time is 30~180min, preferably 60~120min; the atmosphere of the second heat treatment is oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21~100%.

[0015] Further, in step S2, the temperature of the water immersion treatment is 25~100℃; the time of the water immersion treatment is 10~60min; the solid-liquid ratio of the water immersion treatment is 1:2~1:5g / mL; the leaching agent of the water immersion treatment is water.

[0016] Further, in step S3, the number of times of water washing is 1~3 times; the temperature of water washing is 25~100℃; the slurry liquid-solid ratio of water washing is 2:1~5:1mL / g; the stirring time of water washing is 5~40min; the washing liquid obtained after water washing is returned to step S2 as the leaching agent of water immersion treatment.

[0017] Further, in step S3, the ammonium sulfate and the first leaching residue are matched according to the molar ratio SO4 2- :Mn = 1:1~1.5:1.

[0018] Further, in step S3, the temperature of the roasting is 300-550 DEG C; the time of the roasting is 30-180 min.

[0019] Further, the atmosphere of the roasting is oxygen-containing gas atmosphere, and the oxygen partial pressure of the oxygen-containing gas is 21-100%.

[0020] Further, in step S3, the ball-to-material mass ratio of the ball milling is 20:1-2.5:1, and the time of the ball milling is 30-120 min.

[0021] Further, in step S4, the temperature of the water immersion is 25-100 DEG C; the time of the water immersion is 10-60 min; the solid-to-liquid ratio of the water immersion is 1:2-1:5 g / mL; and the leaching agent of the water immersion is water.

[0022] Further, in step S5, the number of the water washing is 1-3 times; the temperature of the water washing is 25-100 DEG C; the slurry-to-liquid ratio of the water washing is 2:1-5:1 mL / g; the stirring time of the water washing is 5-40 min; and the water washing liquid obtained after the water washing is returned to step S4 as the leaching agent of the water immersion.

[0023] Further, in step S1, the flue gas generated by the first heat treatment is absorbed by water to obtain an ammonia water solution, or is absorbed by a sulfuric acid solution to obtain ammonium sulfate by crystallization.

[0024] The ammonium sulfate is returned to step S3 for use.

[0025] Further, in step S4, the pH value of the second leaching liquid is adjusted to 4.5-6.5 before the evaporation crystallization.

[0026] Further, the manganese sulfate product is battery-grade manganese sulfate.

[0027] Further, the magnesium sulfate product is industrial-grade magnesium sulfate.

[0028] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0029] The method for recycling and treating industrial waste salt of electrolytic manganese metal in the application has simple process, mild process conditions, low energy consumption, and low required cost, can eliminate the environmental protection pressure of the storage of the industrial waste salt of electrolytic manganese metal, and can realize the efficient recovery of Mg, Mn, NH4 + / NH3, and S resources in the industrial waste salt of electrolytic manganese metal and the recovery of Ca, and the purity of the recovered manganese sulfate reaches the battery grade.

[0030] The method for recycling and treating industrial waste salt of electrolytic manganese can return all products except the product to the treatment system for reuse, does not produce secondary waste, is clean and environmentally friendly, can reduce the environmental protection pressure of related enterprises, and can increase economic benefits, and is suitable for large-scale industrial application.

[0031] The method for recycling and treating industrial waste salt of electrolytic manganese can return all products except the product to the treatment system for reuse, does not produce secondary waste, is clean and environmentally friendly, can reduce the environmental protection pressure of related enterprises, and can increase economic benefits, and is suitable for large-scale industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The process flow diagram of the method for recycling and treating industrial waste salt of electrolytic manganese. DETAILED DESCRIPTION

[0034] The present application provides a method for recycling and treating industrial waste salt of electrolytic manganese, comprising:

[0035] S1, mixing the industrial waste salt of electrolytic manganese with calcium oxide, first heating to a first temperature for first heat treatment, then heating to a second temperature for second heat treatment, to obtain a treatment product; the first temperature is lower than the second temperature; the second temperature is 500-700 DEG C;

[0036] S2, water immersion treatment and solid-liquid separation are performed on the treatment product to obtain a first leaching residue and a first leaching solution; the first leaching solution is evaporated and crystallized to obtain a magnesium sulfate product;

[0037] S3, the first leaching residue is washed with water and dried, then mixed with ammonium sulfate and ball milled to obtain a mixture; the mixture is calcined to obtain a calcined product;

[0038] S4, the calcined product is water immersed, then solid-liquid separated to obtain a second leaching residue and a second leaching solution; the second leaching solution is evaporated and crystallized to obtain a manganese sulfate product;

[0039] S5, the second leaching residue is washed with water, then solid-liquid separated and dried to obtain industrial gypsum.

[0040] In some preferred embodiments, the calcium oxide and the industrial waste salt of electrolytic manganese are mixed according to a molar ratio of CaO:(2NH4 ++Mn) = 1 : 1 ~ 1.5: 1, preferably 1 : 1 ~ 1.3: 1, for example 1 : 1, 1.05: 1, 1.1 : 1, 1.15: 1, 1.2: 1, 1.25: 1, 1.3: 1, etc.

[0041] In some preferred embodiments, in step S1, the first temperature is 300 ~ 500°C, preferably 400 ~ 500°C, for example 400°C, 420°C, 450°C, 480°C, 500°C; the time of the first heat treatment is 20 ~ 180 min, preferably 45 ~ 90 min, for example 45 min, 60 min, 75 min, 90 min, etc.; the atmosphere of the first heat treatment is an oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21 ~ 100%.

[0042] In some preferred embodiments, in step S1, the second temperature is 600 ~ 700°C, for example 600°C, 620°C, 650°C, 680°C, 700°C; the reaction time is 30 ~ 180 min, preferably 60 ~ 120 min, for example 60 min, 75 min, 90 min, 105 min, 120 min, etc.; the atmosphere of the second heat treatment is an oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21 ~ 100%.

[0043] In some preferred embodiments, in step S2, the temperature of the water immersion treatment is 25 ~ 100°C, for example 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc.; the time of the water immersion treatment is 10 ~ 60 min, for example 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.; the solid-liquid ratio of the water immersion treatment is 1 : 2 ~ 1 : 5 g / mL, for example 1 : 2 g / mL, 1 : 2.5 g / mL, 1 : 3 g / mL, 1 : 3.5 g / mL, 1 : 4 g / mL, 1 : 4.5 g / mL, 1 : 5 g / mL, etc.; the leaching agent of the water immersion is water.

[0044] In some preferred embodiments, in step S3, the water washing is performed for 1-3 times, such as 1 time, 2 times, or 3 times; the water washing is performed at a temperature of 25-100°C, such as 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or 100°C; the water washing is performed at a liquid-to-solid ratio of 2:1-5:1 mL / g, such as 2:1 mL / g, 2.5:1 mL / g, 3:1 mL / g, 3.5:1 mL / g, 4:1 mL / g, 4.5:1 mL / g, or 5:1 mL / g; the water washing is performed for 5-40 min, such as 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, or 40 min; and the water washing solution obtained after the water washing is returned to step S2 as the leaching agent for the water immersion treatment.

[0045] In some preferred embodiments, in step S3, the ammonium sulfate and the first leaching residue are mixed at a molar ratio of SO4 2- :Mn is 1:1-1.5:1, such as 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, or 1.5:1.

[0046] In some preferred embodiments, in step S3, the roasting is performed at a temperature of 300-550°C, preferably 400-500°C, such as 400°C, 420°C, 450°C, 480°C, or 500°C; and the roasting is performed for 30-180 min, preferably 60-120 min, such as 60 min, 75 min, 90 min, 105 min, or 120 min.

[0047] In some embodiments, the roasting is performed in an oxygen-containing gas atmosphere, and the oxygen-containing gas has an oxygen partial pressure of 21-100%.

[0048] In some preferred embodiments, in step S3, the ball milling is performed at a ball-to-material mass ratio of 20:1-2.5:1, such as 2.5:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1; and the ball milling is performed for 30-120 min, such as 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, or 120 min.

[0049] In some preferred embodiments, in step S4, the temperature of the water immersion is 25-100℃, such as 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, etc.; the time of the water immersion is 10-60min, such as 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc.; the solid-liquid ratio of the water immersion is 1:2-1:5g / mL, such as 1:2g / mL, 1:2.5g / mL, 1:3g / mL, 1:3.5g / mL, 1:4g / mL, 1:4.5g / mL, 1:5g / mL, etc.; and the leaching agent of the water immersion is water.

[0050] In some preferred embodiments, in step S5, the number of water washing is 1-3 times, such as 1 time, 2 times, 3 times; the temperature of the water washing is 25-100℃, such as 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, etc.; the liquid-solid ratio of the water washing is 2:1-5:1mL / g, such as 2:1mL / g, 2.5:1mL / g, 3:1mL / g, 3.5:1mL / g, 4:1mL / g, 4.5:1mL / g, 5:1mL / g, etc.; the stirring time of the water washing is 5-40min, such as 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, etc.; and the water washing liquid obtained after the water washing is returned to step S4 as the leaching agent of the water immersion.

[0051] In some preferred embodiments, in step S1, the flue gas generated by the first heat treatment is absorbed by water to obtain an aqueous ammonia solution, or is absorbed by a sulfuric acid solution to obtain ammonium sulfate by crystallization.

[0052] The ammonium sulfate is returned to step S3 for use.

[0053] In some preferred embodiments, in step S4, the pH value of the second leaching liquid is adjusted to 4.5-6.5 before evaporation and crystallization. For example, the pH value is adjusted to 4.5, 5, 5.5, 6, 6.5, etc.

[0054] In some preferred embodiments, the manganese sulfate product is a battery-grade manganese sulfate.

[0055] In some preferred embodiments, the magnesium sulfate product is an industrial-grade magnesium sulfate.

[0056] For the convenience of understanding the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments of the application, but the scope of protection of the present application is not limited to the following specific embodiments.

[0057] Example 1

[0058] A method for recovering industrial waste salt of electrolytic manganese by segmental molten salt treatment, a process flow diagram is shown as follows, comprising the following steps: Figure 1

[0059] (1) The taken industrial waste salt of electrolytic manganese is mixed with calcium oxide according to the molar ratio CaO:(2NH4 +

[0060] (2) The mixture obtained in step (1) is placed in a muffle furnace at 450℃ for 60min to obtain a molten salt deamination product.

[0061] (3) The mixture obtained in step (2) is placed in a muffle furnace at 650℃ for 90min to obtain a molten salt manganese oxide product.

[0062] (4) The molten salt reaction product obtained in step (3) is slurried with deionized water according to the liquid-solid ratio 2:1 mL / g, and then the obtained slurry is placed in a water bath at 50℃ for stirring and water immersion, and the reaction is carried out for 30min, the leaching rate of Mg is 99.95%. Then filtration is carried out to obtain leaching residue and magnesium sulfate leaching solution.

[0063] (5) The magnesium sulfate obtained in step (4) is evaporated and crystallized to obtain MgSO4·7H2O product meeting the requirements of HG / T 2680-2017. The comprehensive recovery rate of magnesium is 99.5%.

[0064] (6) The water immersion residue obtained in step (4) is washed with water for 2 times, the water washing temperature is 50℃; the water washing slurry ratio is 2:1 mL / g; the water washing stirring time is 20min, and then it is mixed with ammonium sulfate according to the molar ratio SO4 2- : Mn = 1.1 and placed in a ball mill jar according to the ball material ratio of 10:1 g / g, and the ball milling time is 60min.

[0065] (7) The mixture obtained in step (6) is placed in a muffle furnace at 500℃ for 120min to obtain a reaction product.

[0066] (8) The reaction product obtained in step (7) is slurried with deionized water according to the liquid-solid ratio 2:1 mL / g, and then the obtained slurry is placed in a water bath at 25℃ for stirring and water immersion, and the reaction is carried out for 20min, the leaching rate of Mn is 99.32%. Then filtration is carried out to obtain leaching residue and manganese sulfate leaching solution.

[0067] ​​(9) The manganese sulfate solution obtained in step (8) is adjusted to a pH value of 6 using concentrated sulfuric acid, and evaporative crystallization is performed to obtain a MnSO4·H2O product meeting HG / T4823-2015. The comprehensive recovery rate of manganese is 99.1%.

[0068] (10) The leaching residue obtained in step (8) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is stirred in a water bath at 50°C for 20 min. The water washing is repeated three times, and then filtration and drying are performed to obtain a building gypsum product. The comprehensive recovery rate of calcium is 99.5%.

[0069] Example 2

[0070] A method for recovering electrolytic manganese industrial waste salt by a staged molten salt treatment, a process flow diagram is as shown in Figure 1 , comprising the following steps:

[0071] (1) The electrolytic manganese industrial waste salt taken is mixed with calcium oxide at a molar ratio of CaO:(2NH4 + + Mn) = 1.2.

[0072] (2) The mixture obtained in step (1) is placed in a muffle furnace at 500°C for 45 min to obtain a molten salt deamination product.

[0073] (3) The mixture obtained in step (2) is placed in a muffle furnace at 700°C for 60 min to obtain a molten salt manganese oxide product.

[0074] (4) The molten salt reaction product obtained in step (3) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 30°C for stirring and water immersion for 20 min. The leaching rate of Mg is 99.92%. Then filtration is performed to obtain a leaching residue and a magnesium sulfate leaching solution.

[0075] (5) The magnesium sulfate obtained in step (4) is evaporated and crystallized to obtain a MgSO4·7H2O product meeting the requirements of HG / T 2680-2017 (industrial grade). The comprehensive recovery rate of magnesium is 99.1%.

[0076] (6) The water immersion residue of step (4) is washed three times at a water washing temperature of 25°C, a water washing slurry liquid-solid ratio of 4:1 mL / g, and a water washing stirring time of 30 min, and then drying is performed. The dried product is mixed with ammonium sulfate at a molar ratio of SO4 2- :Mn = 1.2 in a ball mill jar at a ball material ratio of 8:1 g / g for 90 min.

[0077] (7) The mixture obtained in step (6) was placed in a muffle furnace at 550° C. and reacted for 60 min to obtain a reaction product.

[0078] (8) The reaction product obtained in step (7) was slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g. The resulting slurry was then placed in a 40°C water bath and stirred for 10 minutes. The leaching rate of Mn was 99.85%. The leaching residue and manganese sulfate leachate were then filtered.

[0079] (9) The manganese sulfate solution obtained in step (8) was adjusted to a pH of 6.5 using concentrated sulfuric acid, and evaporated and crystallized to obtain a MnSO4·H2O product that met HG / T 4823-2015. The comprehensive recovery rate of manganese was 99.5% (comprehensive recovery rate is the total recovery rate, calculated as comprehensive recovery rate of Mn = (mass of Mn contained in the MnSO4·H2O product / mass of Mn contained in the low-grade manganese oxide ore) × 100%).

[0080] (10) The leached residue obtained in step (8) was slurried with deionized water at a liquid-to-solid ratio of 2:1 mL / g. The slurry was then placed in a 25°C water bath and stirred and washed for 30 min. The washing was repeated three times, and then filtered and dried to obtain a building gypsum product. The comprehensive recovery rate of calcium was 99.3%.

[0081] Example 3

[0082] A method for recycling electrolytic manganese industry waste salt by segmented molten salt treatment, the process flow chart is as follows Figure 1 As shown, the following steps are included:

[0083] (1) The electrolytic manganese industrial waste salt and calcium oxide are mixed in a molar ratio of CaO: (2NH4 + + Mn) = 1.3 mixed.

[0084] (2) The mixture obtained in step (1) was placed in a muffle furnace at 350°C for reaction for 150 minutes to obtain a molten salt deamination product.

[0085] (3) The mixture obtained in step (2) was placed in a muffle furnace at 550° C. and reacted for 120 min to obtain a molten salt manganese oxide product.

[0086] (4) The molten salt reaction product obtained in step (3) was slurried with deionized water at a liquid-to-solid ratio of 3:1 mL / g. The resulting slurry was then placed in a 70°C water bath and stirred for 40 minutes. The leaching rate of magnesium was 99.95%. The leaching residue and magnesium sulfate leachate were then filtered.

[0087] (5) Evaporate and crystallize the magnesium sulfate obtained in step (4) to obtain MgSO4·7H2O product meeting the requirements of HG / T 2680-2017. The comprehensive recovery of magnesium is more than 99.3%.

[0088] (6) The water leaching residue obtained in step (4) is washed with water for 3 times, the water washing temperature is 60℃, the water washing slurry solid ratio is 3:1 mL / g, the water washing stirring time is 20 min, and then it is dried and mixed with ammonium sulfate according to the molar ratio SO4 2- : Mn = 1.5, and then it is put into a ball mill tank according to the ball material ratio of 6:1 g / g, and the ball milling time is 60 min.

[0089] (7) The mixed material obtained in step (6) is put into a muffle furnace at 450℃ for reaction for 120 min to obtain a reaction product.

[0090] (8) The reaction product obtained in step (7) is slurried with deionized water according to the liquid solid ratio of 3:1 mL / g, and then the obtained slurry is stirred and water leached in a water bath at 50℃ for 20 min, and the leaching rate of Mn is 99.91%. Then filtration is performed to obtain leaching residue and manganese sulfate leaching solution.

[0091] (9) The manganese sulfate solution obtained in step (8) is adjusted to pH 6.5 by using concentrated sulfuric acid, and evaporated and crystallized to obtain MnSO4·H2O product meeting the requirements of HG / T 4823-2015. The comprehensive recovery of manganese is more than 99.8%.

[0092] (10) The leaching residue obtained in step (8) is slurried with deionized water according to the liquid solid ratio of 2:1 mL / g, and then the obtained slurry is stirred and water washed in a water bath at 50℃ for 30 min, and the water washing is repeated for 3 times, and then filtration is performed, and dried to obtain building gypsum product. The comprehensive recovery of calcium is more than 99.9%.

[0093] Example 4

[0094] A method for recovering electrolytic manganese industrial waste salt by segmental molten salt treatment, a process flow chart is shown as follows, which comprises the following steps: Figure 1

[0095] (1) The electrolytic manganese industrial waste salt taken is mixed with calcium oxide according to the molar ratio CaO:(2NH4 + +Mn) = 0.7.

[0096] (2) The mixed material obtained in step (1) is put into a muffle furnace at 450℃ for reaction for 60 min to obtain molten salt deamination product.

[0097] (3) The mixed material obtained in step (2) is put into a muffle furnace at 650℃ for reaction for 90 min to obtain molten salt manganese oxide product.

[0098] ​(4) The molten salt reaction product obtained in step (3) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 50°C for stirring and water immersion, and the reaction is carried out for 30 min, and the leaching rate of Mg is 99.95%. Then filtration is carried out to obtain leaching residue and magnesium sulfate leaching solution.

[0099] (5) The magnesium sulfate obtained in step (4) is evaporated and crystallized to obtain MgSO4·7H2O product, wherein the Mn content is 3.5 wt.%.

[0100] (6) The water immersion residue obtained in step (4) is washed with water for 2 times, the water washing temperature is 50°C; the slurry ratio of water washing is 2:1 mL / g; the stirring time of water washing is 20 min, and then drying is carried out, and ammonium sulfate is mixed with the residue according to a molar ratio of SO4 2- :Mn = 1.1, and then the mixture is placed in a ball mill tank, the ball-to-material ratio is 10:1 g / g, and the ball milling time is 60 min.

[0101] (7) The mixture obtained in step (6) is placed in a muffle furnace at 500°C for 120 min to obtain a reaction product.

[0102] (8) The reaction product obtained in step (7) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 25°C for stirring and water immersion, and the reaction is carried out for 20 min, and the leaching rate of Mn is 98.65%. Then filtration is carried out to obtain leaching residue and manganese sulfate leaching solution.

[0103] (9) The manganese sulfate solution obtained in step (8) is adjusted to a pH value of 6 using concentrated sulfuric acid, and evaporated and crystallized to obtain MnSO4·H2O product meeting HG / T4823-2015. The comprehensive recovery rate of manganese is 78.9%.

[0104] (10) The leaching residue obtained in step (8) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 50°C for stirring and water washing for 20 min, and the water washing is repeated for three times, and then filtration is carried out, and drying is carried out to obtain building gypsum product. The comprehensive recovery rate of calcium is 99.2%.

[0105] Compared with Example 1, the molar ratio of CaO:(2NH4 + +Mn) in step (1) is reduced to 0.7, which leads to a higher Mn content in the magnesium sulfate obtained in step (5), and the recovery rate of manganese sulfate in step (9) is significantly reduced. It is analyzed that this is because the insufficient calcium content leads to a reduced conversion rate of manganese sulfate into manganese oxide, thereby causing part of the manganese to enter the magnesium sulfate leaching solution in the form of manganese sulfate, which on the one hand leads to a higher Mn content in the obtained magnesium sulfate, and on the other hand leads to a reduced recovery rate of manganese sulfate.

[0106] Comparative Example 1

[0107] A method for recovering industrial waste salt of electrolytic manganese by segmental molten salt treatment, comprising the following steps:

[0108] (1) The industrial waste salt of electrolytic manganese is mixed with calcium oxide according to the molar ratio CaO:(2NH4 + + Mn) = 2.

[0109] (2) The mixture obtained in step (1) is placed in a muffle furnace at 450℃ for 60 min to obtain a molten salt deamination product.

[0110] (3) The mixture obtained in step (2) is placed in a muffle furnace at 650℃ for 90 min to obtain a molten salt manganese oxide product.

[0111] (4) The molten salt reaction product obtained in step (3) is slurried with deionized water according to the liquid-solid ratio 2:1 mL / g, and then the obtained slurry is placed in a water bath at 50℃ for stirring and water immersion, and the reaction is carried out for 30 min, and the leaching rate of Mg is 87.23%. Then filtration is carried out to obtain leaching residue and magnesium sulfate leaching solution.

[0112] (5) The magnesium sulfate obtained in step (4) is evaporated and crystallized to obtain MgSO4·7H2O product meeting the requirements of HG / T 2680-2017. The comprehensive recovery rate of magnesium is 85.4%.

[0113] (6) The water immersion residue obtained in step (4) is washed with water for 2 times, the water washing temperature is 50℃, the water washing slurry ratio is 2:1 mL / g, the water washing stirring time is 20 min, and then it is dried and mixed with ammonium sulfate according to the molar ratio SO4 2- :Mn = 1.1 in a ball mill jar according to the ball material ratio of 10:1 g / g, and the ball milling time is 60 min.

[0114] (7) The mixture obtained in step (6) is placed in a muffle furnace at 500℃ for 120 min to obtain a reaction product.

[0115] (8) The reaction product obtained in step (7) is slurried with deionized water according to the liquid-solid ratio 2:1 mL / g, and then the obtained slurry is placed in a water bath at 25℃ for stirring and water immersion, and the reaction is carried out for 20 min, and the leaching rate of Mn is 57.72%. Then filtration is carried out to obtain leaching residue and manganese sulfate leaching solution.

[0116] (9) The manganese sulfate solution obtained in step (8) is adjusted to pH 6 using concentrated sulfuric acid, and evaporated and crystallized to obtain MnSO4·H2O product, wherein the magnesium content is 6.4 wt%.

[0117] (10) The leaching residue obtained in step (8) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is stirred in a water bath at 50°C for 20 min. The water washing is repeated three times, and then filtration is performed. The building gypsum product is dried. The manganese content is 4.5 wt.%.

[0118] In the comparative example, the molar ratio of CaO:(2NH4 + +Mn) in step (1) is increased to 2.0. In step (4), the leaching rate of Mg is reduced, and in step (8), the leaching rate of Mn is reduced. In step (9), the impurity Mg content in manganese sulfate is too high, and the Mn content in the building gypsum product is relatively high. Through analysis, it is found that when the CaO content is too high, the conversion rate of magnesium sulfate to MgO is too high, which leads to a high leaching rate of Mg. In addition, the leaching residue obtained in step (4) contains not only manganese oxide but also MgO. Therefore, in the sulfation roasting process of step (7), both manganese and magnesium are converted into sulfates. However, the amount of ammonium sulfate is determined according to the amount of manganese. Due to the competition of sulfation between Mn and Mg, the conversion rate of Mn to manganese sulfate is significantly reduced, and part of Mn cannot be converted into manganese sulfate. Not only the recovery rate of manganese sulfate is reduced, but also the Mn content in the gypsum residue is increased, and the magnesium content in the manganese sulfate is significantly increased, which reduces the quality of the manganese sulfate.

[0119] Comparative Example 2

[0120] A method for recovering industrial waste salt of electrolytic manganese by a segmented molten salt treatment, comprising the following steps:

[0121] (1) The obtained industrial waste salt of electrolytic manganese is mixed with calcium oxide according to the molar ratio CaO:(2NH4 + + Mn) = 1.

[0122] (2) The mixture obtained in step (1) is placed in a muffle furnace at 650°C for 90 min to obtain a molten salt manganese oxide product.

[0123] (3) The molten salt reaction product obtained in step (2) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is stirred in a water bath at 50°C for 30 min. The leaching rate of Mg is 90.47%. Then filtration is performed to obtain a leaching residue and a magnesium sulfate leaching solution.

[0124] (4) The magnesium sulfate obtained in step (3) is evaporated and crystallized to obtain a MgSO4·7H2O product that meets the requirements of HG / T 2680-2017. The comprehensive recovery rate of magnesium is 87.4%.

[0125] (5) The water leaching residue obtained in step (4) is washed twice, the washing temperature is 50℃, the slurry ratio is 2:1 mL / g, the stirring time is 20 min, and then the residue is dried and mixed with ammonium sulfate according to a molar ratio of SO4 2- : Mn = 1.1 into a ball mill tank, the ball-to-material ratio is 10:1 g / g, and the ball milling time is 60 min.

[0126] (6) The mixture obtained in step (5) is placed in a 500℃ muffle furnace for reaction for 120 min to obtain a reaction product.

[0127] (7) The reaction product obtained in step (6) is slurried with deionized water according to a liquid-to-solid ratio of 2:1 mL / g, and then the obtained slurry is stirred in a water bath at 25℃ for water leaching for 20 min, and the leaching rate of Mn is 96.16%. Then, filtration is performed to obtain leaching residue and manganese sulfate leaching solution.

[0128] (8) The manganese sulfate solution obtained in step (7) is adjusted to a pH of 6 using concentrated sulfuric acid, and evaporation crystallization is performed to obtain MnSO4·H2O product, wherein the magnesium content is 0.8wt%.

[0129] (9) The leaching residue obtained in step (8) is slurried with deionized water according to a liquid-to-solid ratio of 2:1 mL / g, and then the obtained slurry is stirred in a water bath at 50℃ for water washing for 20 min, and the washing is repeated three times, and then filtration is performed, and the dried building gypsum product is obtained, wherein the manganese content is 0.5wt.%.

[0130] Compared with Example 1, step (2) in Example 1 is omitted, the comprehensive recovery rate of Mg is reduced, the Mg content in manganese sulfate is higher, which leads to a decrease in product quality, and a higher Mn content enters the building gypsum product. Analysis shows that this is because, after step (2) is omitted, the reaction is carried out at 650℃, which leads to the decomposition of electrolytic manganese industrial waste salt into sulfur oxides and ammonia, and the oxidation of calcium cannot effectively fix the sulfate in the electrolytic industrial waste salt, so that the conversion rate of manganese to manganese oxide in step (2) in the present comparative example is reduced, and during the water leaching in step (3), the unreacted calcium hydroxide is converted into calcium hydroxide, which reacts with magnesium ions and manganese ions to form hydroxides, resulting in a decrease in the leaching rate of magnesium, and more magnesium enters the leaching residue. In step (6), magnesium and manganese are converted into sulfates. Since ammonium sulfate is added according to the Mn content in the leaching residue, the competition leads to the fact that part of the manganese cannot be converted into manganese sulfate, not only does the obtained manganese sulfate product contain a higher Mg content, but the quality of the manganese sulfate product is reduced, and the Mn content in the obtained building gypsum product is increased, and the Mn loss is increased.

[0131] Comparative Example 3

[0132] A method for recovering electrolytic manganese industrial waste salt by staged molten salt treatment, comprising the following steps:

[0133] Step (1) and (2) are the same as steps (1) and (2) of Example 1.

[0134] (3) Put the mixture obtained in step (2) into a muffle furnace at 475 ℃ for 90 min to obtain a molten salt manganese oxide product.

[0135] (4) Slurry the molten salt reaction product obtained in step (3) with deionized water at a liquid-solid ratio of 2:1 mL / g, and then place the obtained slurry in a water bath at 50 ℃ for stirring and water immersion for 30 min, and the leaching rate of Mg is 94.25%. Then filter to obtain leaching residue and magnesium sulfate leaching solution.

[0136] (5) Evaporate and crystallize the magnesium sulfate obtained in step (4) to obtain MgSO4·7H2O product, and the manganese content in the product is 1.4 wt.%.

[0137] (6) Wash the water immersion residue obtained in step (4) twice at a water washing temperature of 50 ℃; the slurry ratio of water washing is 2:1 mL / g; the stirring time of water washing is 20 min, and then dry and mix with ammonium sulfate according to a molar ratio of SO4 2- :Mn = 1.1 in a ball mill jar, and the ball milling time is 60 min.

[0138] (7) Put the mixture obtained in step (6) into a muffle furnace at 500 ℃ for 120 min to obtain a reaction product.

[0139] (8) Slurry the reaction product obtained in step (7) with deionized water at a liquid-solid ratio of 2:1 mL / g, and then place the obtained slurry in a water bath at 25 ℃ for stirring and water immersion for 20 min, and the leaching rate of Mn is 90.43%. Then filter to obtain leaching residue and manganese sulfate leaching solution.

[0140] (9) Adjust the pH value of the manganese sulfate solution obtained in step (8) to 6 using concentrated sulfuric acid, and evaporate and crystallize the MnSO4·H2O product, and the magnesium content in the product is 1.2 wt.%.

[0141] (10) Slurry the leaching residue obtained in step (8) with deionized water at a liquid-solid ratio of 2:1 mL / g, and then place the obtained slurry in a water bath at 50 ℃ for stirring and water washing for 20 min, repeat the water washing three times, and then filter and dry to obtain gypsum product containing 0.3 wt.% of manganese.

[0142] Compared with Example 1, the reaction temperature in step (3) is reduced to 475℃, the recovery rate of magnesium sulfate is reduced, the manganese content is increased, the magnesium content in the obtained manganese sulfate product is also increased, the quality is reduced, and the Mn content in the gypsum product is increased. Analysis shows that because the conversion rate of Mn to manganese oxide is reduced after the reaction temperature in step (3) is reduced, part of the Mn is leached as manganese sulfate during water leaching in step (4), CaO cannot be completely converted into calcium sulfate, and therefore part of the magnesium is lost due to the reaction of calcium hydroxide with magnesium sulfate during water leaching in step (4), resulting in a decrease in the leaching rate of Mg. In addition, part of the Mn is also leached, resulting in an increase in the Mn content in the obtained magnesium sulfate product and a decrease in the quality of the magnesium sulfate. At the same time, part of the Mg is in the form of magnesium hydroxide precipitate in the leaching residue, so that part of the Mg and Mn in the leaching residue can be converted into sulfates during the subsequent roasting of the leaching residue with ammonium sulfate. The conversion of Mg is easier than that of Mn, and the amount of ammonium sulfate is configured according to the Mn content, so that most of the Mn and part of the Mg in the roasting product are converted into sulfates, and part of the Mn cannot exist in the form of oxide. Therefore, on the one hand, the leaching rate of Mn during leaching in step (8) is reduced, and the obtained leaching solution contains Mg and Mn, resulting in a decrease in the quality of the manganese sulfate obtained by crystallization in step (9). On the other hand, Mn enters the final gypsum product, causing an increase in Mn loss.

[0143] Comparative Example 4

[0144] A method for recovering industrial waste salt of electrolytic manganese by a segmented molten salt treatment, comprising the following steps:

[0145] Steps (1) and (2) are the same as steps (1) and (2) of Example 1.

[0146] (3) The mixture obtained in step (2) is placed in a 800℃ muffle furnace for 90min to obtain a molten salt manganese oxide product.

[0147] (4) The molten salt reaction product obtained in step (3) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a 50℃ water bath for stirring and water leaching for 30min, and the leaching rate of Mg is 92.17%. Then filtration is performed to obtain leaching residue and magnesium sulfate leaching solution.

[0148] (5) The magnesium sulfate obtained in step (4) is evaporated and crystallized to obtain MgSO4·7H2O product meeting the requirements of HG / T 2680-2017. The comprehensive recovery rate of magnesium is 89.5%.

[0149] (6) The water leaching residue obtained in step (4) is washed twice at a water washing temperature of 50℃, a water washing slurry liquid-solid ratio of 2:1 mL / g, a water washing stirring time of 20min, and is dried and mixed with ammonium sulfate at a molar ratio of SO42- : Mn = 1.1 The mixture was put into a ball mill jar, with a ball to material ratio of 10:1 g / g, and ball milling for 60 min.

[0150] (7) The mixture obtained in step (6) was put into a muffle furnace at 500°C for 120 min to obtain a reaction product.

[0151] (8) The reaction product obtained in step (7) was slurried with deionized water at a liquid to solid ratio of 2:1 mL / g, and then the obtained slurry was placed in a water bath at 25°C for stirring and water immersion for 20 min, with an Mn leaching rate of 94.36%. Then filtration was performed to obtain leaching residue and manganese sulfate leaching solution.

[0152] (9) The manganese sulfate solution obtained in step (8) was adjusted to a pH value of 6 using concentrated sulfuric acid, and the evaporated crystalline MnS04-H20 product was obtained, with a magnesium content of 0.7 wt.%.

[0153] (10) The leaching residue obtained in step (8) was slurried with deionized water at a liquid to solid ratio of 2:1 mL / g, and then the obtained slurry was placed in a water bath at 50°C for stirring and water washing for 20 min, with three repeated water washing, and then filtration was performed, and the building gypsum product was obtained by drying. The comprehensive recovery rate of calcium was 99.4%.

[0154] Compared with Example 1, the reaction temperature in step (3) was increased to 800°C in the comparative example, the recovery rate of Mg was reduced, and the Mg content in the obtained manganese sulfate was relatively high, resulting in reduced quality of the manganese sulfate. Through analysis, this is because when the reaction temperature in step (3) is too high, part of the Mn and sulfate in the electrolytic manganese industrial waste salt is decomposed into manganese oxide, so the required amount of calcium oxide for fixing manganese ions is reduced, and the excess calcium oxide converts part of the magnesium ions and sulfate ions into calcium sulfate and magnesium oxide in step (3), thereby reducing the recovery rate of Mg. In addition, part of the Mg enters the leaching residue in the form of magnesium oxide, so that the magnesium oxide is converted into magnesium sulfate in step (7). Due to the competition, the conversion rate of manganese oxide to manganese sulfate is reduced, so the leaching rate of Mn is reduced. In addition, both magnesium sulfate and manganese sulfate are leached into the manganese sulfate solution, so the Mg content in the recovered manganese sulfate is increased, resulting in reduced quality of the manganese sulfate.

[0155] Example 5

[0156] A method for recovering electrolytic manganese industrial waste salt by a segmented molten salt treatment, a process flow chart is shown as follows: Figure 1 The method comprises the following steps:

[0157] Steps (1)-(6) are the same as steps (1)-(6) in Example 1.

[0158] (7) The mixture obtained in step (6) is placed in a muffle furnace at 650℃ for 120 min to obtain a reaction product.

[0159] (8) The reaction product obtained in step (7) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 25℃ for stirring and water immersion for 20 min, and the leaching rate of Mn is 87.32%. Then filtration is performed to obtain leaching residue and a manganese sulfate leaching solution.

[0160] (9) The manganese sulfate solution obtained in step (8) is adjusted to a pH of 6 using concentrated sulfuric acid, and evaporated to crystallize to obtain a MnSO4·H2O product meeting HG / T4823-2015. The comprehensive recovery rate of manganese is 85.7%.

[0161] (10) The leaching residue obtained in step (8) is slurried with deionized water at a liquid-solid ratio of 2:1 mL / g, and then the obtained slurry is placed in a water bath at 50℃ for stirring and water washing for 20 min, and the water washing is repeated three times, and then filtration is performed, and the building gypsum product is obtained after drying, wherein the manganese content is 0.6wt.%.

[0162] The difference between the present embodiment and embodiment 1 is only that the calcination temperature in step (7) is increased to 650℃, and the recovery rate of Mn is significantly reduced, and the building gypsum contains a higher manganese content. It is analyzed that this is because when the calcination temperature in step (7) is too high, the self-decomposition amount of ammonium sulfate increases, which leads to the failure to convert part of the manganese oxide in the residue into manganese sulfate, thereby increasing the manganese loss and reducing the recovery rate.

[0163] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for recovering waste salt from electrolytic manganese industry, characterized in that: include: S1. After mixing electrolytic manganese industrial waste salt with calcium oxide, the mixture is heated to a first temperature for a first heat treatment, and then heated to a second temperature for a second heat treatment to obtain a treated product; the first temperature is lower than the second temperature; the second temperature is 500-700°C; the calcium oxide and electrolytic manganese industrial waste salt are mixed in a molar ratio of CaO:(2NH4 + +Mn) = 1:1 to 1.5:1; in step S1, the first temperature is 300 to 500° C.; S2. performing water leaching and solid-liquid separation on the treated product to obtain a first leaching residue and a first leachate; evaporating and crystallizing the first leachate to obtain a magnesium sulfate product; S3, after the first leaching residue is washed and dried, it is mixed with ammonium sulfate and ball milled to obtain a mixture; the mixture is roasted to obtain a roasted product; the ammonium sulfate and the first leaching residue are mixed at a molar ratio of SO4 2- :Mn is in a ratio of 1:1 to 1.5:1; in step S3, the calcination temperature is 300 to 550°C; S4, water-leaching the roasted product and performing solid-liquid separation to obtain a second leaching residue and a second leachate; the second leachate is evaporated and crystallized to obtain a manganese sulfate product; S5. The second leaching residue is washed with water, then solid-liquid separation and drying are performed to obtain industrial gypsum.

2. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: The calcium oxide and electrolytic manganese industrial waste salt are prepared in a molar ratio of CaO:(2NH4 + +Mn) =1:1~1.3:1 is determined.

3. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: The first temperature is 400-500° C.; the first heat treatment time is 20-180 min; the first heat treatment atmosphere is an oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21-100%.

4. The method for recovering electrolytic manganese industrial waste salt according to claim 3, wherein: The first heat treatment time is 45 to 90 minutes.

5. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S1, the second temperature is 600-700°C; the time of the second heat treatment is 30-180 minutes; the atmosphere of the second heat treatment is an oxygen-containing gas, and the oxygen partial pressure of the oxygen-containing gas is 21-100%.

6. The method for recovering electrolytic manganese industrial waste salt according to claim 5, wherein: In step S1, the second heat treatment is performed for 60 to 120 minutes.

7. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S2, the water immersion treatment temperature is 25 to 100° C.; the water immersion treatment time is 10 to 60 minutes; the solid-liquid ratio of the water immersion treatment is 1:2 to 1:5 g / mL; and the leaching agent of the water immersion treatment is water; In step S3, the number of water washings is 1 to 3 times; the water washing temperature is 25 to 100° C.; the slurry-to-solid ratio of the water washing is 2:1 to 5:1 mL / g; the stirring time of the water washing is 5 to 40 min; and the washing liquid obtained after the water washing is returned to step S2 as a leaching agent for water immersion treatment.

8. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S3, the calcination time is 30 to 180 minutes; The calcination atmosphere is an oxygen-containing gas atmosphere, and the oxygen partial pressure of the oxygen-containing gas is 21 to 100%; In step S3, the ball-to-material mass ratio of the ball milling is 20:1 to 2.5:1, and the ball milling time is 30 to 120 minutes.

9. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S4, the water immersion temperature is 25 to 100° C.; the water immersion time is 10 to 60 minutes; the solid-liquid ratio of the water immersion is 1:2 to 1:5 g / mL; and the leaching agent of the water immersion is water.

10. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S5, the number of water washings is 1 to 3 times; the water washing temperature is 25 to 100° C.; the slurry-to-solid ratio of the water washing is 2:1 to 5:1 mL / g; the stirring time of the water washing is 5 to 40 min; and the washing liquid obtained after the water washing is returned to step S4 as a leaching agent for water immersion.

11. The method for recovering electrolytic manganese industrial waste salt according to claim 1, wherein: In step S1, the flue gas generated by the first heat treatment is absorbed by water to obtain an ammonia solution, or absorbed by a sulfuric acid solution and crystallized to obtain ammonium sulfate; the ammonium sulfate is returned to step S3 for use; In step S4, the pH value of the second leachate is adjusted to 4.5-6.5 and then evaporated and crystallized; The manganese sulfate product is battery-grade manganese sulfate; The magnesium sulfate product is industrial grade magnesium sulfate.

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