A method for resource utilization of cyanex272 raffinate in manganese sulfate production

Abstract

The application discloses a method for recycling raffinate of Cyanex272 in manganese sulfate production, wherein in the first step, liquid alkali is added into the solution and air is introduced, pH is maintained at 8.5-9.0, and reaction is carried out for more than 1h, so that manganese is removed to 2mg / L or below; under the condition of pH=8.5-9.0, calcium basically does not precipitate; under the condition of pH=8.5-9.0, divalent manganese is oxidized into trivalent manganese by air, and precipitates are removed from the solution; compared with the prior art, in which liquid alkali is adjusted to pH above 10 to directly precipitate manganese, the method can save liquid alkali, reduce production cost, and well reduce the content of calcium in manganese slag, and the generated hydroxyl manganese can be used as an oxidizing agent. The method disclosed by the application can make the content of manganese, phosphorus and other impurities in the obtained solution not more than 2mg / L, and the content of calcium not more than 20mg / L, so that the treatment requirements of the Cyanex272 raffinate are met, the purity of the evaporation crystallization product, industrial sodium sulfate, can reach the standard of external sales, the value of the byproduct is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of chemical production technology, specifically relating to a method for the resource utilization of Cyanex 272 raffinate in manganese sulfate production. Background Technology

[0002] In the hydrometallurgical process of cobalt and nickel, manganese, as a by-product, is often used to produce battery-grade manganese sulfate. During this process, Cyanex 272 extractant is used to extract manganese and separate it from calcium. The Cyanex 272 raffinate contains 1-2 g / L calcium, 0.1-1 g / L manganese, 100-300 mg / L total phosphorus, 600-800 mg / L COD, and 20-50 g / L sodium sulfate. The pH of the Cyanex 272 raffinate is approximately 4.5-5.5. In current production processes, liquid alkali precipitation is often used during manganese removal. To precipitate manganese to a acceptable level, the pH needs to be adjusted to 10.0-10.5, which causes some calcium co-precipitation. The manganese hydroxide contains some calcium hydroxide. The manganese hydroxide is generally dissolved and re-enters the extraction section. The presence of calcium increases the load on the extraction line. Moreover, existing technologies often use sodium fluoride for calcium removal, which introduces fluoride. Fluoride residue is a hazardous waste, and the wastewater needs to be defluorinated with resin. The resin regeneration process generates a large amount of wash water that needs to be treated, resulting in high environmental costs. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method for the resource utilization of Cyanex 272 raffinate in manganese sulfate production, specifically including the following:

[0004] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0005] (1) Manganese precipitation: Add liquid alkali to the Cyanex272 raffinate and purge with air to maintain the pH of the solution at 8.5-9.0 to carry out the manganese precipitation reaction; after the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue; at pH=8.5-9.0, calcium will not precipitate. At pH=8.5-9.0, divalent manganese will be oxidized by air to trivalent manganese, forming a precipitate that is removed from the solution. Compared with adjusting the pH to above 10 with liquid alkali to directly precipitate manganese, this method can effectively reduce the calcium content in the manganese residue. The hydroxy manganese generated by this method can be used as an oxidant.

[0006] (2) Calcium precipitation: Sodium carbonate is used for calcium precipitation in this scheme. After adjusting the pH of the solution to 8.5-9.0 in the first step of manganese precipitation, sodium carbonate is added to the solution to carry out the calcium precipitation reaction. Before adding sodium carbonate, the calcium ion concentration is tested. 1 mol of calcium ions is added to 1.2-1.3 mol of sodium carbonate. After the reaction is completed, the solution is filtered to obtain the second filtrate and calcium carbonate residue.

[0007] (3) Phosphorus removal: Add 5‰-10‰ of polyferric solution to the second filtrate, and then add liquid alkali to adjust the pH of the solution to 4.5-5.5 to carry out the phosphorus removal reaction; after the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag;

[0008] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Then stop adding sulfuric acid solution and continue stirring for more than 1 hour.

[0009] (5) Evaporation and crystallization: Add liquid alkali to the third filtrate after removing carbonate ions, adjust the pH of the solution to 6-7, and then enter the MVR for evaporation and crystallization to obtain industrial sodium sulfate.

[0010] Preferably, the mass concentration of the liquid alkali in step (1) is 8-12%; the reaction time of the manganese precipitation reaction is ≥1h.

[0011] Preferably, in step (1), the manganese content in the first filtrate is ≤2 mg / L.

[0012] Preferably, the reaction time of the calcium precipitation reaction in step (2) is ≥0.5h.

[0013] Preferably, in step (2), the calcium content in the second filtrate is ≤20 mg / L.

[0014] Preferably, the reaction temperature of each step (1)-(4) is 50-60℃.

[0015] Preferably, the mass concentration of the liquid alkali in step (3) is 30-35%; the reaction temperature of the phosphorus removal reaction is 50-60℃, and the reaction time is ≥1h.

[0016] Preferably, the phosphorus content in the third filtrate of step (3) is ≤1 mg / L and the COD content is reduced to 150-290 mg / L.

[0017] Preferably, the mass concentration of the liquid alkali in step (5) is 30-35%.

[0018] The beneficial effects of this invention are:

[0019] (1) This invention discloses a method for the resource utilization of Cyanex 272 raffinate in manganese sulfate production. The first step involves adding liquid alkali to the solution and introducing air to maintain a pH of 8.5-9.0. After reacting for more than 1 hour, manganese is removed to 2 mg / L or less. At pH 8.5-9.0, calcium essentially does not precipitate. At pH 8.5-9.0, divalent manganese is oxidized to trivalent manganese by air, forming a precipitate that is removed from the solution. Compared to the prior art of adjusting the pH to above 10 with liquid alkali to directly precipitate manganese, this method saves liquid alkali, reduces production costs, and effectively reduces the calcium content in the manganese slag. Furthermore, the generated hydroxyl manganese can be used as an oxidant. Moreover, this method uses sodium carbonate for calcium precipitation, eliminating the use of hazardous materials and the generation of hazardous waste. The additional carbonate ions can be converted into carbon dioxide, thus not affecting the crystallization of sodium sulfate.

[0020] (2) This invention discloses a method for the resource utilization of Cyanex 272 raffinate in manganese sulfate production. It uses sodium carbonate for calcium removal, avoiding the use of sodium fluoride and producing no harmful fluorides, making it more environmentally friendly. Furthermore, it specifies the pH, reaction time, and reaction temperature for each process step, including manganese precipitation, calcium precipitation, phosphorus removal, and evaporation crystallization, providing the optimal treatment scheme for Cyanex 272 raffinate. This ensures the final treatment effect, ensuring that the content of impurities such as manganese, calcium, and phosphorus in the final solution does not exceed 2 mg / L, meeting the treatment requirements for Cyanex 272 raffinate. Simultaneously, it ensures that the purity of the evaporated crystallized product, industrial sodium sulfate, meets the standards for external sale, increasing the value of by-products and reducing production costs. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the method disclosed in this invention. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments shown below do not limit the scope of the invention as described in the claims. Furthermore, the complete contents of the configurations illustrated in the following embodiments are not limited to those necessary for the solution of the invention as described in the claims.

[0023] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0024] (1) Manganese precipitation: Add 8-12% liquid alkali to the Cyanex272 raffinate and purge with air to maintain the pH of the solution at 8.5-9.0. Carry out the manganese precipitation reaction for ≥1h. After the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue. The manganese content in the first filtrate is ≤2mg / L.

[0025] (2) Precipitation of calcium: Add 1.2-1.3 times the excess of sodium carbonate to the first filtrate to carry out the precipitation reaction. The reaction temperature is 50-60℃ and the reaction time is ≥0.5h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue. The calcium content in the second filtrate is ≤20mg / L.

[0026] (3) Phosphorus removal: Add 5‰-10‰ of polyferric solution to the second filtrate, and then add 30-35% liquid alkali to adjust the pH of the solution to 4.5-5.5 to carry out the phosphorus removal reaction. The reaction temperature is 50-60℃ and the reaction time is ≥1h. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag. The phosphorus content in the third filtrate is ≤1mg / L and the COD content is reduced to 150-290mg / L.

[0027] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Then stop adding sulfuric acid solution and continue stirring for more than 1 hour. The reaction temperature of each step (1)-(4) is 50-60℃.

[0028] (5) Evaporation and crystallization: Add 30-35% liquid alkali to the third filtrate after removing carbonate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0029] Example 1

[0030] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0031] (1) Manganese precipitation: Add 10% liquid alkali to the Cyanex 272 raffinate and purge with air to maintain the pH of the solution at 8.5-9.0 to carry out the manganese precipitation reaction for ≥1h; after the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue.

[0032] (2) Precipitation of calcium: Add 1.3 times the excess of sodium carbonate to the first filtrate to carry out the precipitation reaction. The reaction temperature is 60℃ and the reaction time is ≥0.5h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue.

[0033] (3) Phosphorus removal: Add 10‰ of the polyferric solution to the second filtrate, and then add 35% liquid alkali to adjust the pH of the solution to 4.5-5.5 to carry out the phosphorus removal reaction for ≥1h; after the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0034] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third solution and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 1.2 hours. The reaction temperature of steps (1)-(4) is 60°C.

[0035] (5) Evaporation and crystallization: Add 35% liquid alkali to the third filtrate after removing carbonate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0036] The contents of impurities such as calcium, manganese, and phosphorus in the Cyanex 272 raffinate and the solution treated by the method of this embodiment are shown in Table 1, #1.

[0037] Example 2

[0038] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0039] (1) Manganese precipitation: Add 12% liquid alkali to the Cyanex 272 raffinate and purge with air to maintain the pH of the solution at 8.8-9.0 for manganese precipitation reaction for 1.5 hours; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxyl residue.

[0040] (2) Precipitation of calcium: Add 1.2 times the excess of sodium carbonate to the first filtrate to carry out the precipitation reaction. The reaction temperature is 55℃ and the reaction time is 1h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue.

[0041] (3) Phosphorus removal: Add 8‰ of the polyferric solution to the second filtrate, and then add 30% liquid alkali to adjust the pH of the solution to 4.8-5.0 to carry out the phosphorus removal reaction for 2 hours; after the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0042] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 2 hours. The reaction temperature of steps (1)-(4) is 55℃.

[0043] (5) Evaporation and crystallization: Add 30% liquid alkali to the third filtrate after removing carbonate ions, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0044] The contents of impurities such as calcium, manganese, and phosphorus in the Cyanex 272 raffinate and the solution treated by the method of this embodiment are shown in Table 1, #2.

[0045] Example 3

[0046] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0047] (1) Manganese precipitation: Add 8% liquid alkali to the Cyanex 272 raffinate and purge with air to maintain the pH of the solution at 8.5-8.7 for manganese precipitation reaction for 2 hours; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxyl residue.

[0048] (2) Precipitation of calcium: Add 1.25 times the excess of sodium carbonate to the first filtrate to carry out the precipitation reaction. The reaction temperature is 50℃ and the reaction time is 1h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue.

[0049] (3) Phosphorus removal: Add 5‰ of the polyferric solution to the second filtrate, and then add 33% liquid alkali to adjust the pH of the solution to 4.5-4.7 to carry out the phosphorus removal reaction for 1.5 hours; after the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0050] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 1.5 hours. The reaction temperature of steps (1)-(4) is 57°C.

[0051] (5) Evaporation and crystallization: Add 33% liquid alkali to the third filtrate after removing carbonate ions, adjust the pH of the solution to 6.3-6.5, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0052] The contents of impurities such as calcium, manganese, and phosphorus in the Cyanex 272 raffinate and the solution treated by the method of this embodiment are shown in Table 1, #3.

[0053] Table 1. Impurity content data of Cyanex 272 raffinate before and after treatment in Examples 1-3.

[0054]

[0055] Example 4

[0056] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0057] (1) Manganese precipitation: Add 9% liquid alkali to the Cyanex 272 raffinate and purge with air to maintain the pH of the solution at 8.6-8.9 for manganese precipitation reaction for 1.3 hours; after the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue. The manganese content in the first filtrate is ≤1.8 mg / L.

[0058] (2) Calcium precipitation: Add 1.3 times the excess sodium carbonate to the first filtrate to carry out the calcium precipitation reaction at a temperature of 58°C for 0.8 hours. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue. The calcium content in the second filtrate is ≤0.5 mg / L.

[0059] (3) Phosphorus removal: Add 7‰ of the polyferric solution to the second filtrate, and then add 32% liquid alkali to adjust the pH of the solution to 4.8-5.2 to carry out the phosphorus removal reaction for 1.2 hours. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag. The phosphorus content in the third filtrate is 0.75 mg / L and the COD content is reduced to 200 mg / L.

[0060] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 2.5 hours. The reaction temperature of steps (1)-(4) is 58°C.

[0061] (5) Evaporation and crystallization: Add 34% liquid alkali to the third filtrate after removing carbonate ions, adjust the pH of the solution to 6.8-6.9, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0062] Example 5

[0063] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0064] (1) Manganese precipitation: Add 11% liquid alkali to the Cyanex 272 raffinate and purge with air to maintain the pH of the solution at 8.8-9.0 for manganese precipitation reaction for 2.2 hours; after the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue. The manganese content in the first filtrate is ≤0.8mg / L.

[0065] (2) Calcium precipitation: Add 1.28 times the excess of sodium carbonate to the first filtrate to carry out the calcium precipitation reaction at a reaction temperature of 52℃ for 1.5h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue. The calcium content in the second filtrate is ≤0.3mg / L.

[0066] (3) Phosphorus removal: Add 9‰ of the polyferric solution to the second filtrate, and then add 31% liquid alkali to adjust the pH of the solution to 5.1-5.5 to carry out the phosphorus removal reaction for 2.5 hours. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag. The phosphorus content in the third filtrate is ≤0.5mg / L and the COD content is reduced to 160mg / L.

[0067] (4) Remove carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 2 hours. The reaction temperature of steps (1)-(4) is 52℃.

[0068] (5) Evaporation and crystallization: Add 31% liquid alkali to the third filtrate after removing carbonate ions, adjust the pH of the solution to 6.3-6.6, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0069] Example 6

[0070] A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0071] (1) Manganese precipitation: Add 8.5% liquid alkali to the Cyanex272 raffinate and purge with air to maintain the pH of the solution at 8.5-9.0 for manganese precipitation reaction for 1 hour; after the reaction is completed, filter to obtain the first filtrate and hydroxy manganese residue. The manganese content in the first filtrate is ≤1.5mg / L.

[0072] (2) Calcium precipitation: Add 1.3 times the excess sodium carbonate to the first filtrate to carry out the calcium precipitation reaction at a reaction temperature of 50℃ for 0.7h. After the reaction is completed, filter to obtain the second filtrate and calcium carbonate residue. The calcium content in the second filtrate is ≤0.1mg / L.

[0073] (3) Phosphorus removal: Add 7‰ of the polyferric solution to the second filtrate, and then add 34% liquid alkali to adjust the pH of the solution to 4.9-5.3 to carry out the phosphorus removal reaction for 1.8 hours. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag. The phosphorus content in the third filtrate is ≤0.2mg / L and the COD content is reduced to 190mg / L.

[0074] (4) Removal of carbonate: Slowly add sulfuric acid solution to the third filtrate and stir until no more bubbles are generated. Stop adding sulfuric acid and continue stirring for 1.8 hours. The reaction temperature of steps (1)-(4) is 50°C.

[0075] (5) Evaporation and crystallization: Add 34% liquid alkali to the third filtrate after removing carbonate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for resource utilization of Cyanex 272 raffinate in manganese sulfate production, characterized by, The method comprises the following steps: (1) Manganese precipitation: adding liquid alkali into the Cyanex272 raffinate and passing air into the solution to maintain the pH of the solution at 8.5-9.0 to carry out the manganese precipitation reaction; after the reaction is completed, filtering to obtain a first filtrate and a manganese hydroxide residue; (2) Calcium precipitation: adding an excess of 1.2-1.3 times of sodium carbonate into the first filtrate to carry out the calcium precipitation reaction; after the reaction is completed, filtering to obtain a second filtrate and a calcium carbonate residue; (3) Phosphorus removal: adding a polyferric solution accounting for 5‰-10‰ of the volume of the solution into the second filtrate, and then adding liquid alkali to adjust the pH of the solution to 4.5-5.5 to carry out the phosphorus removal reaction; after the reaction is completed, filtering to obtain a third filtrate and a phosphorus-containing iron residue; (4) Carbonate removal: slowly adding sulfuric acid solution into the third filtrate and stirring until no bubbles are generated, then stopping adding the sulfuric acid solution and continuing to stir for more than 1h; (5) Evaporation crystallization: adding liquid alkali into the third filtrate after the removal of the carbonate to adjust the pH of the solution to 6-7, and then carrying out evaporation crystallization to obtain industrial sodium sulfate.

2. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 1, characterized in that, The mass concentration of the liquid alkali in step (1) is 8-12%; the reaction time of the manganese precipitation reaction is ≥1h.

3. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 2, characterized in that, The manganese content in the first filtrate in step (1) is ≤2mg / L.

4. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 1, characterized in that, The reaction time of the calcium precipitation reaction in step (2) is ≥0.5h.

5. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 4, characterized in that, The calcium content in the second filtrate in step (2) is ≤20mg / L.

6. The method for resource utilization of Cyanex 272 raffinate in manganese sulfate production according to any one of claims 1-5, characterized in that, The reaction temperature of steps (1)-(4) is 50-60℃.

7. A process for the resource utilisation of Cyanex 272 raffinate in the production of manganese sulfate according to any one of claims 1 to 5, characterised in that, The mass concentration of the liquid alkali in step (3) is 30-35%; the reaction temperature of the phosphorus removal reaction is 50-60℃, and the reaction time is ≥1h.

8. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 7, characterized in that, The phosphorus content in the third filtrate in step (3) is ≤1mg / L, and the COD content is reduced to 150-290mg / L.

9. A method for resource utilization of Cyanex 272 raffinate in the production of manganese sulfate according to claim 7, characterized in that, The mass concentration of the liquid alkali in step (5) is 30-35%.

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