Method for resource utilization of electrolytic manganese metal ammonium sulfate slag

Abstract

The application discloses a method for resource utilization of electrolytic manganese metal sulfur ammonium slag, and belongs to the technical field of sulfur ammonium slag recovery. The method comprises the following steps: mixing and dissolving sulfur ammonium slag with water to obtain an ammonium sulfate crude liquid; adding a sulfuration agent to precipitate manganese ions, adding a fluorination agent and adjusting pH to precipitate calcium and magnesium ions; and then performing preliminary filtration through a plate pressure filter, secondary deep filtration through a safety filter and a chelating resin tower, removal of solid particles and metal ions, and obtaining a bipolar membrane electrodialysis feed liquid; feeding the feed liquid into a bipolar membrane electrodialysis stack, under the action of a direct current electric field, ammonium sulfate is dissociated into sulfate ions and ammonium ions, which are combined with H + and OH ‑ generated by the bipolar membrane to generate dilute sulfuric acid and dilute ammonia water; after concentration of the dilute sulfuric acid and stripping distillation of the dilute ammonia water, the dilute sulfuric acid and the dilute ammonia water are respectively fed back to a leaching process of a manganese electrolysis workshop and an electrolytic cell for reuse. The application does not generate polluting gases in the whole process, avoids investment in desulfurization and denitrification equipment, and realizes efficient resource utilization of the sulfur ammonium slag and zero discharge of ammonia and nitrogen.

Description

Technical Field

[0001] This invention belongs to the field of ammonium sulfate slag recycling technology, specifically relating to a method for the resource utilization of electrolytic manganese ammonium sulfate slag. Background Technology

[0002] In the electrolytic manganese hydrometallurgical process, manganese in manganese ore is converted into manganese sulfate through acid dissolution. A qualified manganese sulfate solution is then prepared through neutralization, impurity removal, and purification. During liquid preparation, ammonia water is added to neutralize and adjust the pH of the solution, and the generated ammonium sulfate increases the conductivity of the electrolyte. However, during the static process, crystals gradually precipitate from the electrolyte. These crystals are ammonium sulfate crystals. The large-scale precipitation of these crystals forms ammonium sulfate slag, a waste residue. Direct discharge or stockpiling of this residue not only results in a huge waste of ammonia nitrogen and sulfate resources but also leads to severe soil and water pollution. How to handle ammonium sulfate slag is a key challenge for the industry's transition to green and environmentally friendly practices.

[0003] In recent years, recycling ammonium sulfate slag has become a major method for treating it. For example, the existing technology with patent application number 202410689390.1 and invention title: "Method for Recycling and Reducing Emissions from Ammonium Sulfate Slag Waste" provides the following technical solution: S1: Ammonium sulfate slag treatment section, where the ammonium sulfate slag generated during the electrolytic metal process is separated into solid and liquid phases by pressure filtration, and further dried using crushed manganese and water-washed manganese drying equipment, and then transferred to a pulverizer for crushing; S2: Decomposition furnace treatment section, where the ammonium sulfate slag and ammonia water treated in S1 are sent into the decomposition furnace for high-temperature calcination, and the ammonium sulfate slag is added to the decomposition furnace for decomposition. The amount of ammonium sulfate slag added is increased according to the flue gas emission factor, while the amount of ammonia water added is decreased; S3: Optimized usage, where the amount of ammonia water added is decreased as the amount of ammonium sulfate slag added increases. The usage can be optimized during continuous use until the optimal treatment effect is achieved or the ammonia water is discontinued.

[0004] In the above technology, ammonium sulfate slag is dried by manganese crushing and water washing drying equipment, and then fed into a decomposition furnace for high-temperature calcination along with ammonia water to treat the ammonium sulfate slag. However, the following technical problems still exist: after high-temperature calcination, ammonium sulfate slag will generate nitrogen oxides and sulfur dioxide polluting gases. After being emitted into the atmosphere, these acidic gases will form acid rain, causing environmental pollution and failing to meet environmental protection requirements. If the generated nitrogen oxides and sulfur dioxide polluting gases are to be desulfurized and denitrified, additional desulfurization and denitrification equipment is required, which increases the cost of recycling and treatment. Summary of the Invention

[0005] In view of this, the present invention provides a method for the resource utilization of electrolytic manganese ammonium sulfate slag, in order to solve the technical problem that nitrogen oxides and sulfur dioxide polluting gases are generated during the treatment of ammonium sulfate slag.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for resource utilization of electrolytic manganese ammonium sulfate residue includes the following steps:

[0008] S1. Mix and dissolve the ammonium sulfate residue with water, and stir for a predetermined time to obtain crude ammonium sulfate solution;

[0009] S2. Add a sulfiding agent to the crude ammonium sulfate solution to precipitate and remove heavy metal ions from the crude ammonium sulfate solution, so as to obtain a pretreated crude ammonium sulfate solution, wherein the heavy metal ions are manganese ions;

[0010] S3. Add fluorinating agent to the pretreated crude ammonium sulfate solution and add sodium carbonate to adjust the pH of the pretreated crude ammonium sulfate solution to a predetermined pH, so that calcium and magnesium ions in the pretreated crude ammonium sulfate solution precipitate to obtain a pretreated ammonium sulfate suspension.

[0011] S4. Use a plate press filter to initially filter the pretreated ammonium sulfate suspension. The suspended particles in the pretreated ammonium sulfate suspension are removed by the plate press filter to obtain the pretreated ammonium sulfate solution.

[0012] S5. The pretreated ammonium sulfate solution is further filtered using a security filter and a chelating resin tower. The security filter is provided with filter holes of a predetermined size to filter out solid particles in the pretreated ammonium sulfate solution that exceed the diameter of the filter holes. The chelating resin tower is filled with a predetermined material to chemically adsorb specific ions in the ammonium sulfate solution. Through the two-stage filtration of the security filter and the chelating resin tower, the concentrations of manganese ions, magnesium ions, calcium ions, and solid particles in the ammonium sulfate solution are reduced to predetermined standards to obtain a bipolar membrane electrodialysis feed solution. The specific ions include manganese ions, magnesium ions, and calcium ions.

[0013] S6. The bipolar membrane electrodialysis feed solution is pumped into the bipolar membrane electrodialysis stack and flows into the salt chamber of the stack. Under the action of a DC electric field, the ammonium sulfate in the bipolar membrane electrodialysis feed solution dissociates to generate sulfate ions (SO4). 2− With ammonium ions NH 4+ sulfate ions SO42- 2− Through the anion exchange membrane of the bipolar membrane electrodialysis stack, ions migrate to the acid chamber of the bipolar membrane electrodialysis stack, where they react with hydrogen ions (H+) generated by the bipolar membrane in the acid chamber. + This combines to form dilute sulfuric acid with a concentration of approximately 1.5 mol / L, and the ammonium ion NH₄⁻ 4+ The cation exchange membrane of the bipolar membrane electrodialysis stack migrates to the alkaline chamber of the bipolar membrane electrodialysis stack, where it reacts with hydroxide ions (OH-) generated by the bipolar membrane. -By combining the generated dilute ammonia solution with a concentration of approximately 1.5 mol / L, the feed solution for bipolar membrane electrodialysis is pre-filtered using the aforementioned plate filter and security filter. This effectively prevents solid particles in the feed solution from clogging the channels of the bipolar membrane electrodialysis stack and from mechanically scratching or damaging the bipolar membranes. Furthermore, the use of a chelating resin tower for chemical ion adsorption of the feed solution effectively prevents manganese, magnesium, and calcium ions from forming scale on the ion exchange membranes of the bipolar membrane electrodialysis stack. This avoids problems such as decreased ion exchange membrane permeability, increased membrane resistance, and reduced ion migration efficiency caused by scaling.

[0014] S7. The dilute sulfuric acid in the acid chamber of the bipolar membrane electrodialysis stack is sent to the acid concentration device and concentrated to the predetermined concentration. Then, it is sent to the leaching process of the electrolytic manganese workshop for reuse. The dilute ammonia in the alkali chamber of the bipolar membrane electrodialysis stack is sent to the stripping distillation device and stripped to the predetermined concentration. Then, it is sent to the electrolytic cell of the electrolytic manganese workshop for reuse. In the salt chamber of the bipolar membrane electrodialysis stack, the ammonium sulfate concentration of the bipolar membrane electrodialysis feed solution after passing through the bipolar membrane electrodialysis is reduced to the predetermined concentration. It can then be used to dissolve ammonium sulfate slag. The final products of the resource utilization treatment of ammonium sulfate slag are sulfuric acid and ammonia, with no polluting gas generated.

[0015] Preferably, the predetermined time in step S1 is 30 minutes.

[0016] Preferably, the sulfiding agent in step S2 is either manganese sulfide or barium sulfide.

[0017] Preferably, the fluorinating agent in step S3 is ammonium fluoride, and the predetermined pH is 9-10.

[0018] Preferably, the predetermined size in step S5 is 0.2 μm, the predetermined material is an iminodiacetic acid type chelating resin, and the predetermined standard is Mn. 2+ Concentration <0.05 mg / L, Ca 2+ Concentration <0.5 mg / L, Mg 2+ Concentration <0.5 mg / L, solid particle concentration <0.5 mg / L.

[0019] Preferably, the bipolar membrane electrodialysis stack in step S6 consists of 200 pairs of membrane stacks, and the operating current density of the bipolar membrane electrodialysis stack is 30 mA / cm².

[0020] Preferably, the chemical equation for the acid chamber of the bipolar membrane electrodialysis stack in step S6 is: H + +SO4 2- →H2SO4, the chemical equation for the alkaline chamber of the bipolar membrane electrodialysis stack is: NH 4+ +OH -→NH3·H2O.

[0021] Preferably, in step S7, the predetermined concentration of dilute sulfuric acid is 60%, the predetermined concentration of dilute ammonia is 15%, and the predetermined concentration of ammonium sulfate is 0.1 mol / L.

[0022] The above-mentioned method for the resource utilization of electrolytic manganese ammonium sulfate slag involves dissolving the ammonium sulfate slag in water, adding a sulfiding agent and a fluorinating agent for precipitation, and then subjecting it to three-stage filtration via a plate-press filter, a security filter, and a chelating resin tower to obtain a bipolar membrane electrodialysis feed solution. The three-stage filtration method effectively prevents solid particles and metal ions in the bipolar membrane electrodialysis feed solution from damaging the bipolar membrane electrodialysis stack. The bipolar membrane electrodialysis stack then treats the feed solution, and under the action of direct current, the ammonium sulfate in the feed solution is separated into sulfate ions (SO4) ions. 2− With ammonium ions NH 4+ and respectively react with hydrogen ions H + With hydroxide ions OH - The process involves combining the production of dilute sulfuric acid and dilute ammonia. The dilute sulfuric acid is concentrated, and the dilute ammonia is stripped and distilled before being discharged into the electrolytic manganese production workshop for recycling. In the entire process of resource utilization of electrolytic manganese ammonium sulfate slag, no polluting gases are generated, which meets environmental protection requirements. There is no need to add desulfurization and denitrification equipment for treating polluting gases, thus reducing the cost of ammonium sulfate slag recycling. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a bipolar membrane electrodialysis stack. Detailed Implementation

[0024] To better understand the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0025] A method for resource utilization of electrolytic manganese ammonium sulfate residue includes the following steps:

[0026] S1. Mix and dissolve 1 ton of ammonium sulfate residue with 3 tons of water, and stir for 30 minutes to obtain crude ammonium sulfate solution;

[0027] S2. Add manganese sulfide to the crude ammonium sulfate solution to precipitate and remove manganese ions from the crude ammonium sulfate solution, so as to obtain pretreated crude ammonium sulfate solution.

[0028] S3. Add ammonium fluoride to the pretreated crude ammonium sulfate solution and add sodium carbonate to adjust the pH of the pretreated crude ammonium sulfate solution to 9-10, so that calcium and magnesium ions in the pretreated crude ammonium sulfate solution precipitate to obtain a pretreated ammonium sulfate suspension.

[0029] S4. Use a plate press filter to initially filter the pretreated ammonium sulfate suspension. The suspended particles in the pretreated ammonium sulfate suspension are removed by the plate press filter to obtain the pretreated ammonium sulfate solution.

[0030] S5. The pretreated ammonium sulfate solution is further filtered using a security filter and a chelating resin tower. The security filter has 0.2 μm pores to remove solid particles exceeding the pore diameter from the pretreated ammonium sulfate solution. The chelating resin tower is filled with a predetermined material to chemically adsorb specific ions in the ammonium sulfate solution. Through the two-stage filtration of the security filter and the chelating resin tower, the Mn in the ammonium sulfate solution is reduced. 2+ Concentration <0.05 mg / L, Ca 2+ Concentration <0.5 mg / L, Mg 2+ The concentration is <0.5 mg / L, and the solid particle concentration is <0.5 mg / L, to obtain a bipolar membrane electrodialysis feed solution, wherein the specific ions include manganese ions, magnesium ions, and calcium ions;

[0031] S6, please see Figure 1 The bipolar membrane electrodialysis feed solution is pumped into the bipolar membrane electrodialysis stack and flows into the salt chamber of the stack. Under the action of a DC electric field, the ammonium sulfate in the bipolar membrane electrodialysis feed solution dissociates to generate sulfate ions (SO4). 2− With ammonium ions NH 4+ sulfate ions SO42- 2− Through the anion exchange membrane of the bipolar membrane electrodialysis stack, ions migrate to the acid chamber of the bipolar membrane electrodialysis stack, where they react with hydrogen ions (H+) generated by the bipolar membrane in the acid chamber. + This combines to form dilute sulfuric acid with a concentration of approximately 1.5 mol / L, and the ammonium ion NH₄⁻ 4+ The cation exchange membrane of the bipolar membrane electrodialysis stack migrates to the alkaline chamber of the bipolar membrane electrodialysis stack, where it reacts with hydroxide ions (OH-) generated by the bipolar membrane. − By combining the generated dilute ammonia solution with a concentration of approximately 1.5 mol / L, the feed solution for bipolar membrane electrodialysis is pre-filtered using the aforementioned plate filter and security filter. This effectively prevents solid particles in the feed solution from clogging the channels of the bipolar membrane electrodialysis stack and from mechanically scratching or damaging the bipolar membranes. Furthermore, the use of a chelating resin tower for chemical ion adsorption of the feed solution effectively prevents manganese, magnesium, and calcium ions from forming scale on the ion exchange membranes of the bipolar membrane electrodialysis stack. This avoids problems such as decreased ion exchange membrane permeability, increased membrane resistance, and reduced ion migration efficiency caused by scaling.

[0032] S7. The dilute sulfuric acid in the acid chamber of the bipolar membrane electrodialysis stack is sent to the acid concentration device. After the dilute sulfuric acid is concentrated to 60%, it is sent to the leaching process of the electrolytic manganese workshop for reuse. The dilute ammonia in the alkali chamber of the bipolar membrane electrodialysis stack is sent to the stripping distillation device. After the dilute ammonia is stripped and distilled to 15%, it is sent to the electrolytic cell of the electrolytic manganese workshop for reuse. In the salt chamber of the bipolar membrane electrodialysis stack, after the ammonium sulfate concentration of the bipolar membrane electrodialysis feed solution is reduced to 0.1 mol / L, it can be used to dissolve ammonium sulfate slag. The final products of the resource-based treatment of ammonium sulfate slag are sulfuric acid and ammonia, with no polluting gas generated.

[0033] Furthermore, the bipolar membrane electrodialysis stack described in step S6 consists of 200 pairs of membrane stacks, and the operating current density of the bipolar membrane electrodialysis stack is 30 mA / cm².

[0034] Preferably, the chemical equation for the acid chamber of the bipolar membrane electrodialysis stack in step S6 is: H + +SO4 2- →H2SO4, the chemical equation for the alkaline chamber of the bipolar membrane electrodialysis stack is: NH 4+ +OH - →NH3·H2O.

[0035] Furthermore, the bipolar membrane electrodialysis stack is also equipped with an online cleaning system, which automatically switches to acid washing or alkaline washing mode when the membrane stack voltage rises abnormally to remove the inorganic scale layer on the membrane surface.

[0036] In summary, the above-mentioned method for the resource utilization of electrolytic manganese ammonium sulfate slag involves dissolving the ammonium sulfate slag in water, adding a sulfiding agent and a fluorinating agent for precipitation, and then subjecting it to three-stage filtration via a plate-press filter, a security filter, and a chelating resin tower to obtain a bipolar membrane electrodialysis feed solution. This feed solution is then treated in a bipolar membrane electrodialysis stack, where ammonium sulfate is separated into sulfate ions (SO4) under the action of direct current. 2− With ammonium ions NH 4+ and respectively react with hydrogen ions H + With hydroxide ions OH - By combining the generated dilute sulfuric acid and dilute ammonia, the dilute sulfuric acid is concentrated and the dilute ammonia is stripped and distilled before being discharged into the electrolytic manganese production workshop for recycling. In the entire process of resource utilization of electrolytic manganese ammonium sulfate slag, the produced sulfuric acid and ammonia can be transported into the electrolytic manganese workshop for recycling, realizing the resource utilization of electrolytic manganese ammonium sulfate slag, reducing production costs, and after 720 hours of continuous operation testing, the bipolar membrane stack voltage is stable, no obvious scaling phenomenon is observed, and the conversion rate of ammonium sulfate slag reaches more than 92%, achieving zero emission of ammonia nitrogen and sulfur dioxide pollutants in the electrolytic manganese ammonium sulfate slag treatment process, which meets environmental protection requirements.

[0037] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for the resource utilization of electrolytic manganese ammonium sulfate residue, characterized in that, Includes the following steps: S1. Mix and dissolve the ammonium sulfate residue with water, and stir for a predetermined time to obtain crude ammonium sulfate solution; S2. Add a sulfiding agent to the crude ammonium sulfate solution to precipitate and remove heavy metal ions from the crude ammonium sulfate solution, so as to obtain a pretreated crude ammonium sulfate solution, wherein the heavy metal ions are manganese ions; S3. Add fluorinating agent to the pretreated crude ammonium sulfate solution and add sodium carbonate to adjust the pH of the pretreated crude ammonium sulfate solution to a predetermined pH, so that calcium and magnesium ions in the pretreated crude ammonium sulfate solution precipitate to obtain a pretreated ammonium sulfate suspension. S4. Use a plate press filter to initially filter the pretreated ammonium sulfate suspension. The suspended particles in the pretreated ammonium sulfate suspension are removed by the plate press filter to obtain the pretreated ammonium sulfate solution. S5. The pretreated ammonium sulfate solution is further filtered using a security filter and a chelating resin tower. The security filter is provided with filter holes of a predetermined size to filter out solid particles in the pretreated ammonium sulfate solution that exceed the diameter of the filter holes. The chelating resin tower is filled with a predetermined material to chemically adsorb specific ions in the ammonium sulfate solution. Through the two-stage filtration of the security filter and the chelating resin tower, the concentrations of manganese ions, magnesium ions, calcium ions, and solid particles in the ammonium sulfate solution are reduced to predetermined standards to obtain a bipolar membrane electrodialysis feed solution. The specific ions include manganese ions, magnesium ions, and calcium ions. S6. The bipolar membrane electrodialysis feed solution is pumped into the bipolar membrane electrodialysis stack and flows into the salt chamber of the stack. Under the action of a DC electric field, the ammonium sulfate in the bipolar membrane electrodialysis feed solution dissociates to generate sulfate ions (SO4). 2− With ammonium ions NH 4+ sulfate ions SO42- 2− Through the anion exchange membrane of the bipolar membrane electrodialysis stack, ions migrate to the acid chamber of the bipolar membrane electrodialysis stack, where they react with hydrogen ions (H+) generated by the bipolar membrane in the acid chamber. + This combines to form dilute sulfuric acid with a concentration of approximately 1.5 mol / L, and the ammonium ion NH₄⁻ 4+ The cation exchange membrane of the bipolar membrane electrodialysis stack migrates to the alkaline chamber of the bipolar membrane electrodialysis stack, where it reacts with hydroxide ions (OH-) generated by the bipolar membrane. - By combining the generated dilute ammonia solution with a concentration of approximately 1.5 mol / L, the feed solution for bipolar membrane electrodialysis is pre-filtered using the aforementioned plate filter and security filter. This effectively prevents solid particles in the feed solution from clogging the channels of the bipolar membrane electrodialysis stack and from mechanically scratching or damaging the bipolar membranes. Furthermore, the use of a chelating resin tower for chemical ion adsorption of the feed solution effectively prevents manganese, magnesium, and calcium ions from forming scale on the ion exchange membranes of the bipolar membrane electrodialysis stack. This avoids problems such as decreased ion exchange membrane permeability, increased membrane resistance, and reduced ion migration efficiency caused by scaling. S7. The dilute sulfuric acid in the acid chamber of the bipolar membrane electrodialysis stack is sent to the acid concentration unit and concentrated to a predetermined concentration. Then, it is sent to the leaching process of the electrolytic manganese workshop for reuse. The dilute ammonia in the alkali chamber of the bipolar membrane electrodialysis stack is sent to the stripping distillation unit and stripped to a predetermined concentration. Then, it is sent to the electrolytic cell of the electrolytic manganese workshop for reuse. In the salt chamber of the bipolar membrane electrodialysis stack, the ammonium sulfate concentration of the bipolar membrane electrodialysis feed solution after passing through the bipolar membrane electrodialysis is reduced to a predetermined concentration. It can then be used to dissolve ammonium sulfate slag. The final products of the resource-based treatment of ammonium sulfate slag are sulfuric acid and ammonia, with no polluting gas generated.

2. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The predetermined time mentioned in step S1 is 30 minutes.

3. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The sulfiding agent mentioned in step S2 is either manganese sulfide or barium sulfide.

4. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The fluorinating agent mentioned in step S3 is ammonium fluoride, and the predetermined pH is 9-10.

5. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The predetermined size mentioned in step S5 is 0.2 μm, the predetermined material is iminodiacetic acid type chelating resin, and the predetermined standard is Mn. 2+ Concentration <0.05 mg / L, Ca 2+ Concentration <0.5 mg / L, Mg 2+ Concentration <0.5 mg / L, solid particle concentration <0.5 mg / L.

6. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The bipolar membrane electrodialysis stack described in step S6 consists of 200 membrane stacks, and the operating current density of the bipolar membrane electrodialysis stack is 30 mA / cm².

7. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, The chemical equation for the acid chamber of the bipolar membrane electrodialysis stack in step S6 is: H + +SO4 2- →H2SO4, the chemical equation for the alkaline chamber of the bipolar membrane electrodialysis stack is: NH 4+ +OH - →NH3·H2O.

8. The method for resource utilization of electrolytic manganese ammonium sulfate slag according to claim 1, characterized in that, In step S7, the predetermined concentration of dilute sulfuric acid is 60%, the predetermined concentration of dilute ammonia is 15%, and the predetermined concentration of ammonium sulfate is 0.1 mol / L.

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