Sodium manganese sulfate sulfuration impurity removal method

Abstract

The invention belongs to the technical field of new energy materials, and discloses a sodium manganese sulfate sulfuration impurity removal method, which is divided into two stages of sulfuration, the first stage is that sodium sulfide reacts with manganese sulfate, the pH value is controlled to be 5-6, the second stage is that a small amount of sodium sulfide is added for continuous sulfuration, the pH value is controlled to be stabilized at 6.4-7.0, and the content of calcium, magnesium and other impurities in manganese sulfate is reduced as much as possible through secondary sulfuration. And the generated manganese sulfide is treated in the later stage to obtain manganese sulfate with low content of impurities such as calcium and magnesium. The quality of the refined manganese sulfate solution is improved by using a simple process, the impurity content is reduced, and the quality stability of the manganese sulfate product is improved, so that the market competitiveness of the high-purity manganese sulfate product is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy materials and is a manganese sulfate purification and impurity removal technology. The method can be used to obtain refined high-purity manganese sulfate. Background Art

[0002] High-purity manganese sulfate has a wide range of applications and demands in electronics, batteries and other high-tech fields due to its unique physical and chemical properties. In the battery field, high-purity manganese sulfate is mainly used in the manufacture of lithium-ion batteries. As the positive electrode material of the battery, high-purity manganese sulfate can provide high energy density and high voltage, thereby improving the overall performance of the battery. With the popularization of high-tech products such as electric vehicles and wearable devices, the demand for lithium-ion batteries is also growing, which in turn drives the demand for high-purity manganese sulfate.

[0003] In recent years, with the continuous development of science and technology, the demand for high-purity manganese sulfate has continued to grow. Relevant patent applications include CN201310526817.8, a method for removing impurities from manganese sulfate by full carbonic acid leaching, and CN202111184418.9, a process and device for removing calcium ions from manganese sulfate solution. There are many methods of impurity removal technology in use and in development, but in actual production, there are generally problems such as poor product quality, introduction of new impurities during the impurity removal process, and cumbersome operation. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a sodium manganese sulfate sulfidation purification and impurity removal method, which provides a new technical route for the purification and impurity removal of manganese sulfate. Sodium sulfide is used to purify and remove impurities from manganese sulfate solution, and the content of impurities such as calcium and magnesium in manganese sulfate products can be reduced as much as possible while ensuring low production costs. The purpose is to improve the quality of refined manganese sulfate solution, reduce impurity content, and improve the quality stability of manganese sulfate products with a streamlined process, thereby improving the market competitiveness of high-purity manganese sulfate products. The present invention has the advantages of high degree of automation, low production cost, and low product impurity content.

[0005] The present invention adopts the following technical solutions:

[0006] A sodium manganese sulfate sulfidation impurity removal method comprises the following steps:

[0007] 1) Primary sulfidation: Add MnSO4 solution to the sulfidation tank I, and then add Na2S solution to the sulfidation tank I. The molar number of Na2S is higher than that of MnSO4, and the pH is controlled at 5-6;

[0008] When there is 1 / 2 tank of slurry in vulcanization tank Ⅰ, take a sample to test the pH of the slurry in vulcanization tank Ⅰ and stably control the pH to 5-6;

[0009] 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches 2 / 3, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction, secondary vulcanization, and control the final pH to 6.4-7.0;

[0010] 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

[0011] Preferably, the concentration of the MnSO4 solution in step 1) is 180-200 g / L.

[0012] Preferably, the concentration of Na2S solution in step 1) is 32-39 g / L.

[0013] The pressure of the reaction tank is 0-20 kPa, and the reaction temperature is 30-75°C.

[0014] This patent uses sodium sulfide to adjust the pH value by sulfidation. The sulfidation is divided into two stages. First, in the first stage, sodium sulfide is added to the reaction tank containing manganese sulfate to adjust the pH to 5-6. In the second stage, the slurry is transferred to the sulfidation tank and a small amount of sodium sulfide is added for continuous sulfidation. The high pH value is controlled to be stable at 6.4-7. The content of impurities such as calcium and magnesium in manganese sulfate is reduced as much as possible through secondary sulfidation. The generated manganese sulfide can be treated later to obtain manganese sulfate with lower impurities such as calcium and magnesium. The reaction principle is as follows:

[0015] Sulfide: MnSO4+Na2S→MnS↓+Na2SO4

[0016] The Na introduced by the process of the present invention + Can be separated during filtration.

[0017] The refined manganese sulfate solution of the present invention has Ca≤30ug / mL and Mg≤30ug / mL.

[0018] The use of sodium sulfide to purify and remove impurities from manganese sulfate solution is the only process in use in the country that can be found.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. Efficient separation: The impurity elements in manganese sulfate, such as calcium and magnesium, can be effectively removed by secondary sulfidation of manganese sulfate with sodium sulfide. This method can achieve deep removal of impurities and improve the purity of manganese sulfate.

[0021] 2. Mild conditions: The reaction conditions used are relatively mild and can be carried out at lower temperatures and pressures, thereby reducing dependence on equipment and energy consumption.

[0022] 3. Easy to operate: The process is simple, the device is not complicated, and it is easy to operate in actual production.

[0023] 4. Wide application scope: The process is not only applicable to the removal of impurities in manganese sulfate, but also can be applied to the preparation of other chemicals that need to remove impurity elements.

[0024] 5. High economic benefits: The process has high economic benefits, can increase the added value of manganese sulfate products, and bring more profits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic diagram of the process of the sodium manganese sulfate sulfidation impurity removal method. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] The present invention will be further described below in conjunction with specific embodiments.

[0028] Example 1

[0029] A sodium manganese sulfate sulfidation impurity removal method comprises the following steps:

[0030] 1) Primary vulcanization: Start stirring in the vulcanization tank I, open the MnSO4 feed valve of the vulcanization tank I, put 200g / L MnSO4 solution into the vulcanization tank I, and then add 37g / L Na2S solution into the vulcanization tank I, with the molar number of Na2S being slightly higher than that of MnSO4;

[0031] The pressure of the reaction tank is 15KPa, the reaction temperature is 65℃, when there is 1 / 2 tank of slurry in the vulcanization tank Ⅰ, take a sample to test the pH of the slurry in the vulcanization tank Ⅰ, if the pH value is 5-6, continue the vulcanization;

[0032] If the pH value is greater than 6, appropriately reduce the sulfiding agent flow rate or increase the MnSO4 flow rate (choose 1 from 2); if the pH value is less than 5, appropriately increase the sulfiding agent flow rate or reduce the MnSO4 flow rate (choose 1 from 2) until the pH value is stabilized at 5-6, and the final pH is 5.2;

[0033] 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches 2 / 3, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction. Secondary vulcanization, the pressure of the reaction tank is 10KPa, the reaction temperature is 75℃, and the pH value of the sample test is 6.4-7.0 (precision test paper) for qualified;

[0034] If the pH is greater than 7.0, appropriately reduce the sulfiding agent flow rate; if the pH is lower than 6.4, appropriately increase the sulfiding agent flow rate, control the final pH to 6.4-7.0, and measure 7.0;

[0035] 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

[0036] Example 2

[0037] A sodium manganese sulfate sulfidation impurity removal method comprises the following steps:

[0038] 1) Primary vulcanization: Start stirring in the vulcanization tank I, open the MnSO4 feed valve of the vulcanization tank I, put 190g / L MnSO4 solution into the vulcanization tank I, and then add 39g / L Na2S solution into the vulcanization tank I, where the molar number of Na2S is higher than that of MnSO4;

[0039] The pressure of the reaction tank is 3KPa, the reaction temperature is 75℃, and when there is 1 / 2 tank of slurry in the vulcanization tank Ⅰ, take a sample to test the pH of the slurry in the vulcanization tank Ⅰ. If the pH value is 5-6, continue the vulcanization;

[0040] If the pH value is greater than 6, appropriately reduce the sulfiding agent flow rate or increase the MnSO4 flow rate (choose 1 from 2); if the pH value is less than 5, appropriately increase the sulfiding agent flow rate or reduce the MnSO4 flow rate (choose 1 from 2) until the pH value is stabilized at 5-6, and the final pH is 5.0;

[0041] 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches the 2 / 3 position, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction. Secondary vulcanization, the pressure of the reaction tank is 8KPa, the reaction temperature is 40℃, and the pH value of the sample test is 6.4-7.0 (precision test paper) for qualified;

[0042] If the pH is greater than 7.0, appropriately reduce the sulfiding agent flow rate; if the pH is lower than 6.4, appropriately increase the sulfiding agent flow rate, control the final pH to 6.4-7.0, and measure 6.4;

[0043] 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

[0044] Example 3

[0045] A sodium manganese sulfate sulfidation impurity removal method comprises the following steps:

[0046] 1) Primary vulcanization: Start stirring in the vulcanization tank I, open the MnSO4 feed valve of the vulcanization tank I, put 180g / L MnSO4 solution into the vulcanization tank I, and then add 35g / L Na2S solution into the vulcanization tank I, with the molar number of Na2S being slightly higher than that of MnSO4;

[0047] The pressure of the reaction tank is 18KPa, the reaction temperature is 30℃, when there is 1 / 2 tank of slurry in the vulcanization tank Ⅰ, take a sample to test the pH of the slurry in the vulcanization tank Ⅰ, if the pH value is 5-6, continue the vulcanization;

[0048] If the pH value is greater than 6, appropriately reduce the sulfiding agent flow rate or increase the MnSO4 flow rate (choose 1 from 2); if the pH value is less than 5, appropriately increase the sulfiding agent flow rate or reduce the MnSO4 flow rate (choose 1 from 2) until the pH value is stabilized at 5-6, and the final pH is 5.5;

[0049] 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches the 2 / 3 position, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction. Secondary vulcanization, the pressure of the reaction tank is 16.5KPa, the reaction temperature is 30℃, and the pH value of the sample test is 6.4-7.0 (precision test paper) for qualified;

[0050] If the pH is greater than 7.0, appropriately reduce the sulfiding agent flow rate; if the pH is lower than 6.4, appropriately increase the sulfiding agent flow rate, control the final pH to 6.4-7.0, and measure 6.7;

[0051] 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

[0052] Example 4

[0053] A sodium manganese sulfate sulfidation impurity removal method comprises the following steps:

[0054] 1) Primary vulcanization: Start stirring in the vulcanization tank I, open the MnSO4 feed valve of the vulcanization tank I, put 185g / L MnSO4 solution into the vulcanization tank I, and then add 32g / L Na2S solution into the vulcanization tank I, with the molar number of Na2S being slightly higher than that of MnSO4;

[0055] The pressure of the reaction tank is 2KPa, the reaction temperature is 75℃, and when there is 1 / 2 tank of slurry in the vulcanization tank Ⅰ, take a sample to test the pH of the slurry in the vulcanization tank Ⅰ. If the pH value is 5-6, continue the vulcanization;

[0056] If the pH value is greater than 6, appropriately reduce the sulfiding agent flow rate or increase the MnSO4 flow rate (choose 1 from 2); if the pH value is less than 5, appropriately increase the sulfiding agent flow rate or reduce the MnSO4 flow rate (choose 1 from 2) until the pH value is stabilized at 5-6, and the final pH is 6.0;

[0057] 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches 2 / 3, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction. Secondary vulcanization, the pressure of the reaction tank is 12KPa, the reaction temperature is 60℃, and the pH value of the sample test is 6.4-7.0 (precision test paper) for qualified;

[0058] If the pH is greater than 7.0, appropriately reduce the sulfiding agent flow rate; if the pH is lower than 6.4, appropriately increase the sulfiding agent flow rate, control the final pH to 6.4-7.0, and measure 6.8;

[0059] 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

[0060] The data of manganese sulfate solution obtained by the process method described in the above embodiment are as follows:

[0061] Table 1 Comparison of impurity content of MnSO4 before and after purification and impurity removal using Na2S

[0062]

[0063]

[0064] Note: ND means “Not Detected”

[0065] It can be seen from the above data table 1 that the calcium and magnesium contents in the crude MnSO4 are all higher than 30ppm, while after purification and impurity removal with sodium sulfide using the process of the present invention, the calcium and magnesium contents in the manganese sulfate products obtained in the three experiments are all lower than 30ppm. The purification and impurity removal process of the present invention provides a new method for obtaining high-purity manganese sulfate.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for removing impurities by sulfidation with sodium manganese sulfate, characterized in that: The following steps are involved: 1) Primary sulfidation: Add MnSO4 solution to the sulfidation tank I, and then add Na2S solution to the sulfidation tank I. The molar number of Na2S is higher than that of MnSO4, and the pH is controlled at 5-6; When there is 1 / 2 tank of slurry in vulcanization tank Ⅰ, take a sample to test the pH of the slurry in vulcanization tank Ⅰ and stably control the pH to 5-6; 2) Secondary vulcanization: When the slurry level in the vulcanization tank I reaches 2 / 3, open the inlet and outlet valves of the vulcanization tank I pump and the inlet valve of the vulcanization tank II pump, start the vulcanization pump, and then adjust the valve of the sodium sulfide solution to mix the slurry in the vulcanization tank I and the Na2S solution and pump them into the vulcanization tank II for reaction, secondary vulcanization, and control the final pH to 6.4-7.0; 3) Filter press separation and purification: The qualified slurry after secondary sulfidization is separated by filter press, and the liquid is sampled for inspection. The solid obtained by filter press separation is manganese sulfide. Manganese sulfide is added to sulfuric acid to react to generate manganese sulfate solution. The endpoint pH is controlled to retain some impurities in the solid phase, and filtered again with a filter press to obtain a clear refined manganese sulfate solution.

2. A method for removing impurities by sulfidation of sodium manganese sulfate as claimed in claim 1, characterized in that: In step 1), the concentration of MnSO4 solution is 180-200 g / L.

3. A method for removing impurities by sulfidation of sodium manganese sulfate as claimed in claim 1, characterized in that: In step 1), the concentration of Na2S solution is 32-39 g / L.

4. A method for removing impurities by sulfidation of sodium manganese sulfate as claimed in claim 1, characterized in that: The pressure of the reaction tank is 0-20 kPa, and the reaction temperature is 30-75°C.

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