CN114671466A - High-purity manganese sulfate and method for preparing high-purity manganese sulfate by using solubility property - Google Patents

Abstract

The invention relates to high-purity manganese sulfate, which is characterized in that the content of manganese in the high-purity manganese sulfate is more than 32%, the content of K, Na, Ca and Mg impurities is less than 0.1%, and the content of heavy metal impurities and Fe impurities is less than 0.001%. The method can provide the high-purity manganese sulfate meeting the requirement of the lithium ion battery anode material, has the advantages of simple process, easy operation and low cost, and provides wide prospects for the industrial application of the high-purity manganese sulfate.

Description

A kind of high-purity manganese sulfate and method for preparing high-purity manganese sulfate by utilizing solubility property

technical field

The invention relates to the field of manganese sulfate, in particular to a high-purity manganese sulfate and a method for preparing high-purity manganese sulfate by utilizing solubility properties.

Background technique

Manganese sulfate is a very important basic manganese salt with a wide range of uses. At present, the production methods of high-purity manganese sulfate mainly include chemical precipitation method, electrolysis method, high temperature and high pressure crystallization method, etc. When manganese is enriched, a large amount of impurities also enter the leaching solution at the same time, so the leached manganese sulfate solution must be purified to remove impurities to ensure the purity of MnSO ₄ products.

At present, high-purity manganese sulfate is generally obtained from industrial-grade manganese sulfate after purification. Industrial-grade manganese sulfate contains many impurities, such as potassium salt, sodium salt, calcium salt and other metal salt impurities. In the process of removing these impurities, generally Impurities are relatively easy to remove, and because the chemical properties of calcium sulfate, magnesium sulfate and manganese sulfate are very similar, in the purification process, impurity calcium salts and magnesium salts are difficult to remove from the final product, resulting in excessive impurities in the product.

At present, the high-purity manganese sulfate solution cannot be obtained in the current process or the refining cost is relatively high. For example, Chinese patent CN102923783A discloses a battery-grade high-purity manganese sulfate monohydrate and a preparation method thereof. The preparation method is as follows: pyrolusite, pyrite or pyrite and industrial sulfuric acid are used as raw materials, hydrogen peroxide is added first, the temperature is controlled at 50-70 DEG C, BaS is added, the temperature is controlled at 30-50 DEG C, and hydrofluoric acid is added. , by adding the neutralizing agent MnCO ₃ to adjust to 5-6, then adding polyaluminum sulfate and polyacrylamide solution for flocculation and precipitation, after filtering, adding activated carbon to stand for adsorption, and finally passing into the circulation device equipped with activated alumina balls, and then The crystals were concentrated under normal pressure, washed and dried to obtain high-purity manganese sulfate monohydrate. For example, Chinese patent CN103626235A relates to a method for preparing high-purity manganese sulfate by recrystallization. In this invention, the method for preparing high-purity manganese sulfate by recrystallization takes ordinary manganese sulfate as the raw material, and obtains high-purity manganese sulfate through secondary pressure filtration and four-time recrystallization, which meets the index requirements of high-purity manganese sulfate. This shows that the recrystallization method is adopted. It is technically feasible to prepare high-purity manganese sulfate.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a high-purity manganese sulfate with low K, Na, Ca, Mg impurity content, low heavy metal impurity and Fe impurity content, and high manganese content, which can meet the needs of the positive electrode material of lithium ion batteries, and also provides a high-purity manganese sulfate. The invention discloses a method for preparing high-purity manganese sulfate by utilizing solubility properties with low cost, small investment and good product effect.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a high-purity manganese sulfate, wherein the manganese content in the high-purity manganese sulfate is more than 32%, and the impurity contents of K, Na, Ca and Mg are all less than 0.1%, and The contents of heavy metal impurities and Fe impurities are both lower than 0.001%.

Preferably, the heavy metal impurities include one or more of Co, Ni, Zn, Cu, Pb, Cr, and Cd.

A method of utilizing solubility properties to prepare high-purity manganese sulfate, comprising the steps:

In step 1, the crude manganese sulfate product is dissolved in water, and stirred at room temperature for 2 hours to obtain a 50% sample solution 1;

In step 2, after the 50% sample solution 1 obtained in the first step is allowed to stand for 15 hours, centrifugation and filtration are performed to obtain a filtrate 1 and a filter residue 1. The filtrate 1 is used for recycling, and the filter residue 1 is manganese sulfate precipitation;

Step 3, washing the manganese sulfate precipitation to meet the washing requirements to obtain manganese sulfate solid;

Step 4, adding water to the solid manganese sulfate, stirring at room temperature for 2h, to obtain sample solution 2;

Step 5, filter the sample solution 2 obtained in the step 4 to obtain a filtrate 2 and a filter residue 2, the filtrate 2 is a manganese sulfate solution, and the filter residue 2 is used for recycling;

Step 6, the manganese sulfate solution obtained in the step 5 is crystallized with a rotary evaporator, and the crystallization is stopped when the precipitated solid is about to pass the mother liquor, and then filtered to obtain the manganese sulfate solid;

In step 7, the solid manganese sulfate obtained in the step 6 is washed three times, dried and weighed to obtain a high-purity manganese sulfate product.

Preferably, the manganese sulfate crude product in the step 1 contains a large amount of metal elements, wherein the K ⁺ , Na ⁺ , Ca ²⁺ , Mg ^{2 +} impurity content is relatively high, and the water added in the step 1 and the step 4 is all It is deionized water, and the amount of water added is controlled to ensure that the solid-liquid ratio is 1:1.

Preferably, the temperature of the oil bath during the crystallization of the rotary evaporator in the sixth step is set to 120°C.

Preferably, the drying temperature in the seventh step is set to 80°C.

Preferably, in the step 1, the crude product of manganese sulfate is dissolved in water at constant temperature in a water bath.

Preferably, the filtration in all steps uses a vacuum suction filtration device.

Preferably, the washing requirement in the third step is that the solution does not become turbid when the BaCl ₂ solution is added to the washed solution.

Compared with the prior art, the present invention has the following beneficial effects:

1, the preparation method of the present invention can significantly reduce the content of K, Na, Ca, Mg impurities, heavy metal impurities and Fe impurities contained in the manganese sulfate solution after industrial manganese sulfate or manganese ore is leached with sulfuric acid, especially The impurity content of K, Na, Ca, and Mg is less than 0.1%, while the content of heavy metal impurities and Fe impurities is less than 0.0005%, and the manganese content in the obtained high-purity manganese sulfate is more than 32%, which can meet the requirements of power lithium-ion battery cathode materials. The need for high-purity manganese sulfate for ternary materials;

2. The process of the present invention only utilizes the solubility difference between manganese sulfate and other sulfates to separate it, avoiding the addition of other chemical reagents and complex chemical reactions, and does not require complex and expensive operating equipment itself, the process is relatively simple and easy to control, and the process The cost is relatively low, which provides a broad prospect for the industrial application of high-purity manganese sulfate.

Description of drawings

Fig. 1 is the schematic flow chart of the present invention;

Fig. 2 is the solubility curve schematic diagram of manganese sulfate at different temperatures;

Fig. 3 is the solubility table of different sulfates in manganese sulfate crude product;

Remarks: All data in Figure 3 are the solubility of aqueous solution at 1 atm, and the unit is g/100mL.

Detailed ways

The present invention will be described in detail below with reference to FIGS. 1-3 . The exemplary embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

A high-purity manganese sulfate, wherein the manganese content in the high-purity manganese sulfate is more than 32%, the contents of K, Na, Ca and Mg impurities are all less than 0.1%, and the contents of heavy metal impurities and Fe impurities are all less than 0.001%, The heavy metal impurities include one or more of Co, Ni, Zn, Cu, Pb, Cr, and Cd.

A method of utilizing solubility properties to prepare high-purity manganese sulfate, comprising the steps:

Step 1, add water to the crude manganese sulfate product and put it into a water bath to dissolve, because the dissolving process has a little exothermic phenomenon, the reaction temperature can be kept constant in the water bath, and the crude manganese sulfate in step 1 contains a large amount of metal elements, Among them, the impurity content of K ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ is relatively high, and the water is added while stirring during the adding process, and the amount of water added is controlled to maintain a solid-liquid ratio of 1:1. Stir at room temperature for 2h to fully dissolve the crude manganese sulfate product to obtain 50% sample solution 1;

Step 2, after the 50% sample solution 1 obtained in the first step is allowed to stand for 15 hours, centrifuge and filter to obtain filtrate 1 and filter residue 1. The solid-liquid separation can be better achieved by standing and centrifugation. Although there are impurities in the filtrate 1 , but its manganese content is also high. When it accumulates to a certain amount, it can be processed centrally, so as to be recycled and reused. The filter residue 1 is the precipitation of manganese sulfate, and only the filter residue 1 is retained in this filtration. Large sulfates, such as Fe ²⁺ , Na ⁺ , K ⁺ etc.;

Step ₃ , washing the manganese sulfate precipitation to meet the washing requirements, specifically adding a BaCl solution to the washed solution, if the solution does not remain turbid, the washing requirements are met, otherwise, the precipitation needs to be washed continuously until the washing requirements are met. , and finally obtain manganese sulfate solid;

Step 4, add water to the solid manganese sulfate, and control the amount of water added to ensure that the solid-liquid ratio is 1:1, and stir at room temperature for 2 hours to obtain sample solution 2;

Step 5, filter the sample solution 2 obtained in step 4 to obtain filtrate 2 and filter residue 2, the filtrate 2 is a manganese sulfate solution, and the filter residue 2 is used for recycling, and only the filtrate 2 is retained here to separate the solubility. Smaller sulfates such as CaSO ₄ ;

Step 6, the manganese sulfate solution obtained in the step 5 is crystallized with a rotary evaporator, and the oil bath temperature during the crystallization of the rotary evaporator is set to 120 ° C. According to the solubility of manganese sulfate, reversal will occur, that is, as the temperature increases. High, the solubility of manganese sulfate will increase first and then decrease, so using the particularity of manganese sulfate solubility with temperature change, it can be further separated from other impurity ions by controlling the crystallization temperature, and the amount of the remaining mother liquor needs to be controlled during crystallization If the mother liquor is all evaporated to dryness, other residual impurity ions will also be precipitated. If the mother liquor remains too much, the product will be lost too much, so when the precipitated solid is about to pass the mother liquor, that is, when the mother liquor is small, the crystallization process is ended, Then filter to obtain manganese sulfate solid;

In step 7, the solid manganese sulfate obtained in step 6 is washed three times, dried at a temperature of 80° C., and weighed to obtain a high-purity manganese sulfate product.

The water added in all steps is deionized water, and the filtration in all steps uses a vacuum suction filtration device. During filtration, the solution is slowly poured into the funnel to prevent the bottom sediment from being poured into the funnel.

Example 1

Take 50g of crude manganese sulfate product, add 50mL of deionized water to dissolve, the amount of deionized water added to ensure that the solid-liquid ratio is 1:1, stir at room temperature for 2h, make the volume to 50% of the sample solution 1, dissolve the crude manganese sulfate product in water, and at room temperature Stir for 2 hours to obtain 50% sample solution 1, let the 50% sample solution 1 stand for 15 hours to make solid-liquid layers, centrifuge and filter to obtain filtrate 1 and filter residue 1. In this step, only filter residue 1 and other metals with higher solubility are retained. Sulfate will remain in filtrate 1, separate from it, filter residue 1 is manganese sulfate precipitation, and manganese sulfate solid is obtained after manganese sulfate precipitation is fully washed, and deionized water is added in the manganese sulfate solid, and the solid-liquid ratio is also controlled to be 1: 1. Stir at room temperature for 2 hours to obtain sample solution 2. At this time, the color of sample solution 2 is darker. It can be preliminarily determined that the content of manganese sulfate in this solution is higher. After fully dissolving sample solution 2, filter to obtain filtrate 2 and filter residue 2. Only the filtrate 2 is left in one step, the slightly soluble CaSO ₄ is left in the filter residue 2, and the filtrate 2 is a manganese sulfate solution. Finally, the manganese sulfate solution is concentrated and crystallized with a rotary evaporator to control the temperature, and the manganese sulfate solid is obtained by filtration. Wash, dry and weigh to obtain a pink high-purity manganese sulfate product.

The following table data is the quality of the product of Example 1:

element unit Crude manganese sulfate Example 1 product Mn (manganese) % 36.17 34.82 Ca (Calcium) % 0.180 0.020 Fe (iron) % 0.007 <0.0005 K (potassium) % 0.002 0.001 Mg (magnesium) % 0.480 0.100 Na (sodium) % 0.150 0.025

Example 2

Take 100g of crude manganese sulfate product, add 100mL of deionized water to dissolve, the amount of deionized water added to ensure that the solid-liquid ratio is 1:1, stir at room temperature for 2 hours, and dilute to 50% of the sample solution 1, the crude manganese sulfate product is dissolved in water, and at room temperature Stir for 2 hours to obtain 50% sample solution 1, let the 50% sample solution 1 stand for 15 hours to make solid-liquid layers, centrifuge and filter to obtain filtrate 1 and filter residue 1. In this step, only filter residue 1 and other metals with higher solubility are retained. Sulfate will remain in filtrate 1, separate from it, filter residue 1 is manganese sulfate precipitation, and manganese sulfate solid is obtained after manganese sulfate precipitation is fully washed, and deionized water is added in the manganese sulfate solid, and the solid-liquid ratio is also controlled to be 1: 1. Stir at room temperature for 2 hours to obtain sample solution 2. At this time, the color of sample solution 2 is darker. It can be preliminarily determined that the content of manganese sulfate in this solution is higher. After fully dissolving sample solution 2, filter to obtain filtrate 2 and filter residue 2. Only the filtrate 2 is left in one step, the slightly soluble CaSO ₄ is left in the filter residue 2, and the filtrate 2 is a manganese sulfate solution. Finally, the manganese sulfate solution is concentrated and crystallized with a rotary evaporator to control the temperature, and the manganese sulfate solid is obtained by filtration. Wash, dry and weigh to obtain a pink high-purity manganese sulfate product.

The following table data is the quality of the product of Example 2:

Example 3

Take 25g of crude manganese sulfate product, add 25mL of deionized water to dissolve, the amount of deionized water added to ensure that the solid-liquid ratio is 1:1, stir at room temperature for 2h, dilute to 50% of sample solution 1, dissolve the crude manganese sulfate product in water, and at room temperature Stir for 2 hours to obtain 50% sample solution 1, let the 50% sample solution 1 stand for 15 hours to make solid-liquid layers, centrifuge and filter to obtain filtrate 1 and filter residue 1. In this step, only filter residue 1 and other metals with higher solubility are retained. Sulfate will remain in filtrate 1, separate from it, filter residue 1 is manganese sulfate precipitation, and manganese sulfate solid is obtained after manganese sulfate precipitation is fully washed, and deionized water is added in the manganese sulfate solid, and the solid-liquid ratio is also controlled to be 1: 1. Stir at room temperature for 2 hours to obtain sample solution 2. At this time, the color of sample solution 2 is darker. It can be preliminarily determined that the content of manganese sulfate in this solution is higher. After fully dissolving sample solution 2, filter to obtain filtrate 2 and filter residue 2. Only the filtrate 2 is left in one step, the slightly soluble CaSO ₄ is left in the filter residue 2, and the filtrate 2 is a manganese sulfate solution. Finally, the manganese sulfate solution is concentrated and crystallized with a rotary evaporator to control the temperature, and the manganese sulfate solid is obtained by filtration. Wash, dry and weigh to obtain a pink high-purity manganese sulfate product.

The following table data is the quality of the product of Example 3:

element unit Crude manganese sulfate Example 3 product Mn (manganese) % 36.17 36.24 Ca (Calcium) % 0.180 0.022 Fe (iron) % 0.007 <0.0005 K (potassium) % 0.002 0.001 Mg (magnesium) % 0.480 0.075 Na (sodium) % 0.150 0.021

It can be seen from the product quality of Example 1, Example 2 and Example 3 that the preparation method of the present invention can significantly reduce K, Na and Ca contained in industrial manganese sulfate or manganese sulfate leached with sulfuric acid from manganese ore. , Mg impurities, heavy metal impurities and Fe impurities, especially the content of K, Na, Ca, Mg impurities can be lower than 0.1%, while the content of heavy metal impurities and Fe impurities is lower than 0.0005%, the obtained high-purity manganese sulfate The manganese content is more than 32%, and the basic principle of the present invention is to utilize the solubility difference between manganese sulfate and other sulfates to remove impurity ions in three steps. Fe ²⁺ , Na ⁺ , K ⁺ etc. are removed by filtration. In the second step, metal ions whose solubility is less than manganese sulfate are left in the filter residue 2 and removed, such as CaSO ₄ . The third step uses the characteristics of different sulfate solubility with temperature. In the process of recrystallization, the method utilizes their physical properties to separate them, avoiding the addition of other chemical reagents and complex chemical reactions, and has greater practical value when applied to actual processes.

The technical solutions provided by the embodiments of the present invention have been described in detail above. The principles and implementations of the embodiments of the present invention are described in this paper by using specific examples. The descriptions of the above embodiments are only applicable to help understand the embodiments of the present invention. At the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation and application scope. To sum up, the contents of this specification should not be construed as limitations of the present invention.

Claims (9)

1. High-purity manganese sulfate is characterized in that: the content of manganese in the high-purity manganese sulfate is more than 32%, the content of K, Na, Ca and Mg impurities is lower than 0.1%, and the content of heavy metal impurities and Fe impurities is lower than 0.001%.

2. The high-purity manganese sulfate according to claim 1, wherein: the heavy metal impurities comprise one or more of Co, Ni, Zn, Cu, Pb, Cr and Cd.

3. A method for preparing high-purity manganese sulfate according to any one of claims 1-2 by using solubility properties, which comprises the following steps:

step one, adding water to a crude manganese sulfate product for dissolving, and stirring for 2 hours at normal temperature to obtain a 50% sample solution 1;

step two, standing the 50% sample solution 1 obtained in the step one for 15 hours, centrifuging, and filtering to obtain a filtrate 1 and a filter residue 1, wherein the filtrate 1 is used for recycling, and the filter residue 1 is manganese sulfate precipitate;

washing the manganese sulfate precipitate until the manganese sulfate precipitate meets the washing requirement to obtain a manganese sulfate solid;

adding water into the manganese sulfate solid, and stirring for 2 hours at normal temperature to obtain a sample solution 2;

step five, filtering the sample solution 2 obtained in the step four to obtain a filtrate 2 and a filter residue 2, wherein the filtrate 2 is a manganese sulfate solution, and the filter residue 2 is used for recycling;

step six, crystallizing the manganese sulfate solution obtained in the step five by using a rotary evaporator, and then filtering to obtain a manganese sulfate solid;

and seventhly, washing the manganese sulfate solid obtained in the sixth step for three times, drying and weighing to obtain a high-purity manganese sulfate product.

4. The method for preparing high-purity manganese sulfate according to claim 3, wherein the solubility property of the manganese sulfate is as follows: the manganese sulfate crude product in the step I contains a large amount of metal elements, wherein K is⁺、Na⁺、Ca²⁺、Mg²⁺And (3) the impurity content is higher, the water added in the first step and the fourth step is deionized water, and the added water amount is controlled to ensure that the solid-to-liquid ratio is 1: 1.

5. The method for preparing high-purity manganese sulfate according to claim 4, wherein the solubility property of the manganese sulfate is as follows: the oil bath temperature during the rotary evaporator crystallization in the sixth step was set to 120 ℃.

6. The method for preparing high-purity manganese sulfate according to claim 5, wherein the solubility property of the manganese sulfate is as follows: and in the seventh step, the drying temperature is set to be 80 ℃.

7. The method for preparing high-purity manganese sulfate according to claim 3, wherein the solubility property of the manganese sulfate is as follows: and (3) dissolving the manganese sulfate crude product in a water bath kettle in constant-temperature water.

8. The high-purity manganese sulfate and the method for preparing the high-purity manganese sulfate by using the solubility property according to claim 3, wherein the method comprises the following steps: a reduced-pressure suction filtration device was used for filtration in all steps.

9. The method for preparing high-purity manganese sulfate according to claim 3, wherein the solubility property of the manganese sulfate is as follows: the washing requirement in the third step is that BaCl is added into the washed solution₂The solution did not become cloudy.

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