A method for treating cyanex272 raffinate in manganese sulfate production

Abstract

The application discloses a treatment method for Cyanex272 raffinate in manganese sulfate production, sodium fluoride in the prior art is replaced by sodium phosphate to precipitate calcium ions, no hazardous waste is generated in the treatment process, and since the treatment of the Cyanex272 raffinate itself needs to remove phosphorus, no pollutants are additionally introduced, the safety of the treatment process is improved, and the environmental protection cost is effectively reduced. In addition to removing calcium by using phosphoric acid, the method also limits specific process parameters such as pH, reaction time and reaction temperature of processes such as manganese precipitation, calcium precipitation, phosphorus removal and evaporation crystallization, provides an optimal treatment scheme for the Cyanex272 raffinate, ensures the final treatment effect, so that the content of impurities such as manganese and phosphorus in the obtained solution is not more than 1 mg / L, and the content of calcium is not more than 201 mg / L, the treatment requirements of the Cyanex272 raffinate are met, meanwhile, 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 treating 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 production, Cyanex 272 extractant is used to extract manganese and separate it from calcium. The Cyanex 272 raffinate obtained after extraction contains 1-2 g / L of calcium, 0.1-1 g / L of manganese, 100-300 mg / L of total phosphorus, 600-800 mg / L of COD, and 20-50 g / L of sodium sulfate. The pH of the Cyanex 272 raffinate is approximately 4.5-5.5. In existing production processes, sodium fluoride is commonly used for calcium removal. This method introduces fluoride, and the fluoride slag is classified as hazardous waste. Furthermore, the wastewater requires subsequent resin defluorination, and the resin regeneration process generates a large amount of wash water that needs treatment, 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 treating Cyanex 272 raffinate in manganese sulfate production, specifically including the following:

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

[0005] (1) Manganese precipitation: Add liquid alkali to the Cyanex 272 raffinate to maintain the pH of the solution at 10-10.5 and carry out the manganese precipitation reaction; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue; the manganese hydroxide residue obtained in this step can be returned to the previous process for dissolution, which can effectively recover manganese. In this process, about 30% of calcium will precipitate. Some calcium hydroxide will be mixed in the manganese hydroxide. The liquid alkali added in this process should not be too concentrated, and it is advisable to control it at 10%. Adding too concentrated liquid alkali will cause an increase in calcium co-precipitation.

[0006] (2) Precipitation of calcium: Add 1.2-1.3 times the excess of sodium phosphate to the first filtrate to carry out the precipitation reaction; after the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue;

[0007] Ksp[CaF2]=2.7×10 -11

[0008] Ksp[Ca3(PO4)2]=1.04×10 -24

[0009] Based on the solubility product constant, calcium phosphate is less soluble than calcium fluoride, therefore sodium phosphate is used as a precipitant to remove calcium precipitate.

[0010] (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.

[0011] (4) Evaporation and crystallization: Add liquid alkali to the third filtrate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0012] Preferably, the mass concentration of the liquid alkali in step (1) is 8-12%; and the reaction time of the manganese precipitation reaction is ≥0.5h.

[0013] Preferably, in step (1), the manganese content in the first filtrate is ≤1 mg / L; and the calcium content in the first filtrate is 25-35% lower than that in the Cyanex 272 raffinate.

[0014] Preferably, the reaction temperature of the calcium precipitation reaction in step (2) is 50-60℃ and the reaction time is ≥0.5h.

[0015] Preferably, in step (2), the calcium content in the second filtrate is ≤20 mg / L.

[0016] 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.

[0017] Preferably, the phosphorus content in the third filtrate of step (3) is ≤1 mg / L and the COD content is reduced to 200-250 mg / L.

[0018] Preferably, the mass concentration of the liquid alkali in step (4) is 30-35%.

[0019] The beneficial effects of this invention are:

[0020] (1) The present invention discloses a method for treating Cyanex 272 raffinate in the production of manganese sulfate, which uses sodium phosphate instead of sodium fluoride in the prior art to precipitate calcium ions. No hazardous waste is generated during the treatment process. Since the treatment of Cyanex 272 raffinate itself requires phosphorus removal, no additional pollutants are introduced. This method can improve the safety of the treatment process while effectively reducing environmental protection costs.

[0021] (2) The present invention discloses a method for treating Cyanex 272 raffinate in the production of manganese sulfate. In addition to using sodium phosphate to remove calcium, it also limits the specific process parameters such as pH, reaction time, and reaction temperature of each process flow such as manganese precipitation, calcium precipitation, phosphorus removal, and evaporation crystallization. It provides the best treatment scheme for Cyanex 272 raffinate, ensuring the final treatment effect. The content of impurities such as manganese, calcium, and phosphorus in the final solution does not exceed 1 mg / L, which meets the treatment requirements of Cyanex 272 raffinate. At the same time, it ensures that the purity of industrial sodium sulfate, the product of evaporation crystallization, can meet the standards for external sale, thereby increasing the value of by-products and reducing production costs. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the method disclosed in this invention. Detailed Implementation

[0023] 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.

[0024] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0025] (1) Manganese precipitation: Add 8-12% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10-10.5, and carry out the manganese precipitation reaction for ≥0.5h. After the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue. The manganese content in the first filtrate is ≤1mg / L. The calcium content in the first filtrate is 25-35% lower than that in the Cyanex 272 raffinate.

[0026] (2) Calcium precipitation: Add 1.2-1.3 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 50-60℃ and the reaction time is ≥0.5h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue. The calcium content in the second filtrate is ≤20mg / L.

[0027] (3) Phosphorus removal: Add 5‰-10‰ of polyferric solution to the second filtrate, followed by adding 30-35% liquid alkali to adjust the pH to 4.5-5.5, and carry out the phosphorus removal reaction at a temperature of 50-60℃ for ≥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 200-250mg / L.

[0028] (4) Evaporation and crystallization: Add liquid alkali with a mass concentration of 30-35% to the third filtrate, 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 treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0031] (1) Manganese precipitation: Add 8% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10-10.3, and carry out the manganese precipitation reaction for 1 hour; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue;

[0032] (2) Calcium precipitation: Add 1.2 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 50℃ and the reaction time is 1h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue.

[0033] (3) Phosphorus removal: Add 5‰ of the polyferric solution to the second filtrate, and then add 30% liquid alkali to adjust the pH of the solution to 4.5-5.0. The phosphorus removal reaction is carried out at 50℃ for 1 hour. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0034] (4) Evaporation and crystallization: Add 30% liquid alkali to the third filtrate, adjust the pH of the solution to 6-6.5, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0035] 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.

[0036] Example 2

[0037] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0038] (1) Manganese precipitation: Add 12% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10.2-10.5, and carry out the manganese precipitation reaction for 0.8 h; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue;

[0039] (2) Calcium precipitation: Add 1.3 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 60℃ and the reaction time is 0.8h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue.

[0040] (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 4.8-5.5 to carry out the phosphorus removal reaction. The reaction temperature is 60℃ and the reaction time is 2h. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0041] (4) Evaporation and crystallization: Add 35% liquid alkali to the third filtrate, adjust the pH of the solution to 6.8-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0042] 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.

[0043] Example 3

[0044] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0045] (1) Manganese precipitation: Add 10% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10.1-10.4, and carry out the manganese precipitation reaction for 2 hours; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue.

[0046] (2) Calcium precipitation: Add 1.25 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 55℃ and the reaction time is 2h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue.

[0047] (3) Phosphorus removal: Add 8‰ of the polyferric solution to the second filtrate, and then add 32% liquid alkali to adjust the pH of the solution to 4.9-5.2 to carry out the phosphorus removal reaction. The reaction temperature is 55℃ and the reaction time is 2h. After the reaction is completed, filter to obtain the third filtrate and phosphorus-containing iron slag.

[0048] (4) Evaporation and crystallization: Add 32% liquid alkali to the third filtrate, adjust the pH of the solution to 6.9-7.4, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0049] 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.

[0050] As can be seen from the data in Table 1, the contents of calcium, manganese, COD and TP in the Cyanex 272 raffinate after treatment by the method disclosed in this invention are significantly reduced, indicating that the treatment method disclosed in this invention is effective.

[0051] Table 1. Impurity content data of Cyanex 272 raffinate before and after treatment in Examples 1-3.

[0052]

[0053] Example 4

[0054] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0055] (1) Manganese precipitation: Add 11% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10.1-10.2, and carry out the manganese precipitation reaction for 1.5 hours; after the reaction, filter to obtain the first filtrate and manganese hydroxide residue; the manganese content in the first filtrate is ≤1 mg / L; the calcium content in the first filtrate is 32% lower than the calcium content in the Cyanex 272 raffinate;

[0056] (2) Calcium precipitation: Add 1.28 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 58℃ and the reaction time is 1.5h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue. The calcium content in the second filtrate is ≤20mg / L.

[0057] (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 4.7-5.3 to carry out the phosphorus removal reaction at 58℃ for 1.5h. 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 220mg / L.

[0058] (4) Evaporation and crystallization: Add 32% liquid alkali to the third filtrate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0059] Example 5

[0060] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0061] (1) Manganese precipitation: Add 9% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10-10.1, and carry out the manganese precipitation reaction for 0.5 h; after the reaction, filter to obtain the first filtrate and manganese hydroxide filter residue; the manganese content in the first filtrate is ≤0.9 mg / L; the calcium content in the first filtrate is 28% lower than the calcium content in the Cyanex 272 raffinate;

[0062] (2) Calcium precipitation: Add 1.25 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 56℃ and the reaction time is 0.5h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue. The calcium content in the second filtrate is ≤15mg / L.

[0063] (3) Phosphorus removal: Add 6‰ of the polyferric solution to the second filtrate, and then add 31% liquid alkali to adjust the pH of the solution to 4.8-5.1 to carry out the phosphorus removal reaction at 56℃ for 1 hour. 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 250mg / L.

[0064] (4) Evaporation and crystallization: Add 30% liquid alkali to the third filtrate, adjust the pH of the solution to 6.8-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0065] Example 6

[0066] A method for treating Cyanex 272 raffinate in manganese sulfate production includes the following steps:

[0067] (1) Manganese precipitation: Add 12% liquid alkali to the Cyanex 272 raffinate, maintain the pH of the solution at 10.4-10.5, and carry out the manganese precipitation reaction for 3 hours; after the reaction, filter to obtain the first filtrate and manganese hydroxide residue; the manganese content in the first filtrate is ≤0.4mg / L; the calcium content in the first filtrate is 35% lower than the calcium content in the Cyanex 272 raffinate;

[0068] (2) Calcium precipitation: Add 1.3 times the excess of sodium phosphate to the first filtrate to carry out the calcium precipitation reaction. The reaction temperature of the calcium precipitation reaction is 60℃ and the reaction time is 3h. After the reaction is completed, filter to obtain the second filtrate and calcium phosphate residue. The calcium content in the second filtrate is ≤13mg / L.

[0069] (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 4.6-5.3 to carry out the phosphorus removal reaction at 60℃ for 3 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 ≤0.3mg / L and the COD content is reduced to 200mg / L.

[0070] (4) Evaporation and crystallization: Add 33% liquid alkali to the third filtrate, adjust the pH of the solution to 6.8-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

[0071] 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 treating Cyanex 272 raffinate in manganese sulfate production, characterized in that, Includes the following steps: (1) Manganese precipitation: Add liquid alkali to the Cyanex 272 raffinate to maintain the pH of the solution at 10-10.5 and carry out the manganese precipitation reaction; after the reaction is completed, filter to obtain the first filtrate and manganese hydroxide residue; (2) Calcium precipitation: Add 1.2-1.3 times the excess of sodium phosphate to the first filtrate to carry out the calcium 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 phosphate residue. (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. 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. (4) Evaporation and crystallization: Add liquid alkali to the third filtrate, adjust the pH of the solution to 6-7, and then carry out evaporation and crystallization to obtain industrial sodium sulfate.

2. The method for treating Cyanex 272 raffinate in manganese sulfate production 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 ≥0.5h.

3. The method for treating Cyanex 272 raffinate in manganese sulfate production according to claim 2, characterized in that, Step (1) The manganese content in the first filtrate is ≤1 mg / L; the calcium content in the first filtrate is 25-35% lower than that in the Cyanex 272 raffinate.

4. The method for treating Cyanex 272 raffinate in manganese sulfate production according to claim 1, characterized in that, Step (2) The calcium content in the second filtrate is ≤20mg / L.

5. The method for treating Cyanex 272 raffinate in manganese sulfate production according to any one of claims 1-4, characterized in that, The mass concentration of the liquid alkali in step (3) is 30-35%.

6. The method for treating Cyanex 272 raffinate in manganese sulfate production according to claim 5, characterized in that, In step (3), the phosphorus content in the third filtrate is ≤1 mg / L and the COD content is reduced to 200-250 mg / L.

7. The method for treating Cyanex 272 raffinate in manganese sulfate production according to claim 5, characterized in that, The mass concentration of the liquid alkali in step (4) is 30-35%.

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