Battery-grade high-purity manganese sulfate and preparation process thereof

Abstract

The invention provides battery-grade high-purity manganese sulfate and a preparation process thereof.The preparation process comprises the steps that manganese oxide ore and pyrite are added into water to be evenly mixed, then sulfuric acid is added for a reaction, after the reaction reaches the end point, a first impurity removal agent is added into a reaction system for impurity removal, and a manganese sulfate solution is obtained after filtering; heating and pre-concentrating the manganese sulfate solution to obtain a manganese sulfate concentrated solution; adding sulfuric acid into the manganese sulfate concentrated solution for reaction, and dehydrating to obtain manganese sulfate powder; after the manganese sulfate powder is re-dissolved by using sulfuric acid, adding a second impurity removal agent into the re-dissolved solution to remove impurities; and heating and crystallizing the solution subjected to impurity removal, and dehydrating to obtain the battery-grade high-purity manganese sulfate powder. The preparation process provided by the invention can realize preparation of high-purity manganese sulfate only through one-time crystallization, and has the advantages of low energy consumption, low cost and no fluorine.

Description

Technical Field

[0001] The invention relates to the technical field of manganese sulfate preparation, and in particular to battery-grade high-purity manganese sulfate and a preparation process thereof. Background Art

[0002] As a new generation of environmentally friendly, high-energy batteries, lithium-ion batteries have become one of the focuses of the development of the battery industry. The positive electrode material is the core of lithium batteries. Lithium manganese oxide, nickel-manganese binary materials, and nickel-cobalt-manganese ternary materials are important positive electrode materials for lithium-ion batteries. To obtain high-quality manganese-based positive electrode materials, the purity problem of manganese-based raw materials must first be solved. Whether it is manganese sulfate used directly to produce ternary materials or manganese dioxide or other forms of manganese oxide used to produce lithium manganese oxide, battery-grade high-purity manganese sulfate must first be obtained.

[0003] The main characteristics of battery-grade high-purity manganese sulfate are high purity and low impurity content. The difficulty of impurity removal during the production process is the removal of Ca, Mg, K, and Na in the product. In the related art, the main processes for producing battery-grade high-purity manganese sulfate are: recrystallization method, metal manganese sheet method, fluorination method, etc. However, the above processes all have disadvantages, such as high energy consumption of recrystallization method, high cost of metal manganese sheet method, and high fluorine content and strong corrosion to equipment in the product obtained by fluorination method.

[0004] Therefore, based on the above problems, there is an urgent need to provide a battery-grade high-purity manganese sulfate and a preparation process thereof. Summary of the invention

[0005] The embodiment of the present invention provides a battery-grade high-purity manganese sulfate and a preparation process thereof. The preparation process can realize the preparation of high-purity manganese sulfate with only one crystallization, and has the advantages of low energy consumption, low cost and no fluorine.

[0006] In a first aspect, the present invention provides a process for preparing battery-grade high-purity manganese sulfate, the preparation process comprising the following steps:

[0007] (1) adding manganese oxide ore and pyrite to water and mixing them evenly, then adding sulfuric acid to react, and after the reaction reaches an end point, adding a first impurity remover to the reaction system to remove impurities, and filtering to obtain a manganese sulfate solution;

[0008] (2) heating the manganese sulfate solution for pre-concentration to obtain a manganese sulfate concentrated solution;

[0009] (3) adding sulfuric acid to the manganese sulfate concentrate to react, and obtaining manganese sulfate powder after dehydration;

[0010] (4) after re-dissolving the manganese sulfate powder with water, adding a second impurity remover to the re-dissolved solution to remove impurities;

[0011] (5) The impurity-removed solution is heated and crystallized, and the battery-grade high-purity manganese sulfate powder is obtained after dehydration.

[0012] Preferably, before step (1), the method further comprises the steps of acid washing and water washing the manganese oxide ore and the pyrite ore respectively.

[0013] More preferably, during the pickling process, the content of sulfuric acid is 3-10% of the content of the manganese oxide ore or pyrite, and during the water washing process, the mass ratio of the water content to the Gabonese oxide ore or pyrite is (2-3):1.

[0014] Preferably, in step (1), the content of pyrite is 25-30% of the content of manganese oxide ore, the mass ratio of the total amount of pyrite and Gabon manganese oxide to water is 1:(2-3), and the content of sulfuric acid is 0.42-0.55 times the content of manganese oxide ore.

[0015] Preferably, in step (1), the reaction temperature is 85-90°C and the reaction time is 6-8h.

[0016] Preferably, in step (1), before adding the first impurity remover to the reaction system for impurity removal, the step further includes adding a neutralizing agent to the reaction system to adjust the pH value to above 5.0.

[0017] More preferably, the neutralizing agent is calcium oxide.

[0018] Preferably, in step (1), the first impurity remover comprises barium sulfide and hydrogen peroxide.

[0019] More preferably, the amount of barium sulfide added is 3-7 kg / m 3 The amount of hydrogen peroxide added is 0.2-2kg / m 3 .

[0020] Preferably, in step (2), the heating temperature is 85-90° C. and the heating time is 6-8 h.

[0021] Preferably, in step (2), the concentration of the manganese sulfate concentrate is 43-45 wt%.

[0022] Preferably, in step (3), the amount of sulfuric acid added is 400-600 Kg / m 3 .

[0023] Preferably, in step (3), the reaction temperature is 20-80°C and the reaction time is 2-3h.

[0024] Preferably, in step (4), the concentration of the return solution is 40-45% by weight, the second impurity remover is hydrogen peroxide, and the amount of the second impurity remover added is 0.2-2 kg / m 3 .

[0025] Preferably, before adding the second impurity remover to the return solution for impurity removal, the method further comprises adding metallic manganese powder to the return solution to adjust the pH value of the return solution to above 4.5.

[0026] Preferably, in step (5), the temperature of the heating crystallization is above 95°C, and the concentration of the solution after heating crystallization is 53-60 ppm.

[0027] In a second aspect, the present invention provides a battery-grade high-purity manganese sulfate prepared by the preparation process described in any one of the first aspects above.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] In the present invention, firstly, two mineral resources, manganese oxide ore and pyrite, are used as raw materials, sulfuric acid is added to react under certain conditions, and a targeted impurity remover is added to the reaction system to remove impurities, so as to obtain a manganese sulfate solution; then, the manganese sulfate solution is heated and pre-concentrated, so that calcium sulfate impurities in the solution are precipitated under the common ion effect, so as to reduce the calcium sulfate impurities in the manganese sulfate concentrated solution; further, sulfuric acid is added to the manganese sulfate concentrated solution again for acid precipitation, so that easily soluble magnesium impurities and the like are retained in the solution, and manganese sulfate powder with higher purity is precipitated; finally, the manganese sulfate powder is re-dissolved by sulfuric acid and impurities are removed again, and battery-grade high-purity manganese sulfate powder can be obtained after heating and crystallization; it can be seen that in the present invention, a plurality of processes are combined and carried out step by step, and battery-grade high-purity manganese sulfate can be obtained by heating and crystallization only once, and the invention has the advantages of low energy consumption, low cost and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 The present invention provides a process flow chart for preparing battery-grade high-purity manganese sulfate. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] The present invention provides a preparation process of battery-grade high-purity manganese sulfate, which comprises the following steps:

[0034] (1) adding manganese oxide ore and pyrite to water and mixing them evenly, then adding sulfuric acid to react, and after the reaction reaches an end point, adding a first impurity remover to the reaction system to remove impurities, and filtering to obtain a manganese sulfate solution;

[0035] (2) heating the manganese sulfate solution for pre-concentration to obtain a manganese sulfate concentrated solution;

[0036] (3) adding sulfuric acid to the manganese sulfate concentrate to react, and obtaining manganese sulfate powder after dehydration;

[0037] (4) after re-dissolving the manganese sulfate powder with water, adding a second impurity remover to the re-dissolved solution to remove impurities;

[0038] (5) The impurity-removed solution is heated and crystallized, and the battery-grade high-purity manganese sulfate powder is obtained after dehydration.

[0039] In the embodiment of the present invention, firstly, two mineral resources, manganese oxide ore and pyrite, are used as raw materials, sulfuric acid is added and reacted under certain conditions, and a targeted impurity remover is added to the reaction system for impurity removal to obtain a manganese sulfate solution, and then the manganese sulfate solution is heated and pre-concentrated, so that calcium sulfate impurities in the solution are precipitated under the common ion effect to reduce the calcium sulfate impurities in the manganese sulfate concentrate, and further, sulfuric acid is added to the manganese sulfate concentrate again for acid precipitation, so that easily soluble magnesium impurities and the like are retained in the solution, and manganese sulfate powder with higher purity is precipitated, and finally, the manganese sulfate powder is re-dissolved with sulfuric acid and impurities are removed again, and battery-grade high-purity manganese sulfate powder can be obtained after heating and crystallization; it can be seen that in the present invention, a plurality of processes are combined and carried out step by step, and battery-grade high-purity manganese sulfate can be obtained by only one heating and crystallization, which has the advantages of low energy consumption, low cost and high yield.

[0040] According to some preferred embodiments, before step (1), the steps of acid washing and water washing the manganese oxide ore and the pyrite are also included; during the acid washing process, the content of sulfuric acid is 3-10% (for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%) of the content of the manganese oxide ore or the pyrite, and during the water washing process, the ratio of the mass content of water to the Gabonese oxide ore or the pyrite is (2-3):1 (for example, it can be 2:1, 2.5:1 or 3:1).

[0041] For manganese oxide ore and pyrite with high content of calcium and magnesium impurities, before manganese oxide and pyrite react, in the embodiment of the present invention, a certain mass of manganese oxide ore and pyrite can be added to sulfuric acid for pickling for about 1 hour. During the pickling process, part of the calcium and magnesium impurities in the manganese oxide ore and pyrite are acidified, and then the manganese oxide ore and pyrite after pickling and dehydration are added to the washing bucket for washing for about 1 hour, so as to further remove the acid solution and calcium and magnesium impurities remaining on the surface of manganese oxide ore and pyrite. In this way, the impurities such as calcium and magnesium in manganese oxide ore and pyrite can be partially removed in advance through the pickling and washing steps, effectively reducing their content in the reaction leaching solution. At the same time, in the embodiment of the present invention, by the reasonable control of the ore raw material and sulfuric acid content during the pickling process, the soluble impurities such as calcium and magnesium in the two ore raw materials can be effectively removed while consuming as little sulfuric acid as possible.

[0042] According to some preferred embodiments, in step (1), the content of pyrite is 25-30% of the content of manganese oxide ore (for example, it can be 25%, 26%, 27%, 28%, 29% or 30%), the mass ratio of the total amount of pyrite and manganese oxide to water is 1: (2-3) (for example, it can be 1: 2, 1: 2.5 or 1: 3), and the content of sulfuric acid is 0.42-0.55 times the content of manganese oxide ore (for example, it can be 0.42 times, 0.45 times, 0.48 times, 0.5 times or 0.55 times); in step (1), the reaction temperature is 85-90 ° C (for example, it can be 85 ° C, 88 ° C, 89 ° C or 90 ° C), and the reaction time is 6-8 h (for example, it can be 6 h, 7 h or 8 h).

[0043] In the embodiment of the present invention, Gabon manganese oxide ore with high manganese and manganese plus iron content is used, and a certain content of pyrite is used as a reducing agent to perform an oxidation-reduction reaction in a sulfuric acid solution system. By controlling the contents of the two ore raw materials and the sulfuric acid solution during the reaction process, it is beneficial to keep a small amount of sulfuric acid as much as possible in the solution when generating a manganese sulfate solution and an iron sulfate solution, thereby ensuring better reaction efficiency and economy.

[0044] According to some preferred embodiments, in step (1), before adding the first impurity remover to the reaction system for impurity removal, the step further includes adding a neutralizing agent to the reaction system to adjust the pH value to above 5.0; the neutralizing agent is calcium oxide.

[0045] According to some preferred embodiments, in step (1), the first impurity remover comprises barium sulfide and hydrogen peroxide; the addition amount of the barium sulfide is 3 to 7 kg / m 3 (For example, it can be 3Kg / m 3 , 4Kg / m 3 , 5Kg / m 3 , 6Kg / m 3 or 7Kg / m 3 ), the amount of hydrogen peroxide added is 0.2-2kg / m 3 (For example, it can be 0.2Kg / m 3 , 0.5Kg / m 3 , 1Kg / m 3 , 1.5Kg / m 3 or 2Kg / m 3 ), the mass concentration of hydrogen peroxide is 30%.

[0046] After the redox reaction, the impurity ferric sulfate is introduced into the solution system, and other metal impurities such as iron and aluminum, and heavy metal impurities (such as cobalt, nickel, zinc, etc.) are contained in the two ore raw materials. Therefore, in the embodiment of the present invention, the first impurity remover is used to remove the heavy metal impurities in the current reaction system respectively. Since the solution system after the reaction is an acidic system, before adding the first impurity remover, in the embodiment of the present invention, calcium oxide is first used to neutralize the reaction system to adjust the pH value of the solution system to above 5.0. In this way, it is not only conducive to the hydrolysis and precipitation of iron and aluminum metal ion impurities, but also can avoid the barium sulfide in the first impurity remover from being added to the solution system to be reacted, so that the barium sulfide and heavy metal impurities (cobalt, nickel, zinc) can undergo a replacement reaction to generate heavy metal precipitates, and the addition of hydrogen peroxide can oxidize the iron heavy metal element or divalent iron ions into trivalent iron ions, so as to facilitate their hydrolysis and precipitation. Finally, after there are no heavy metals and iron and aluminum impurities in the detection system, the solution can be taken after filter pressing to remove the heavy metal impurities and other impurities.

[0047] According to some preferred embodiments, in step (2), the heating temperature is 85-90°C (for example, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C), and the heating time is 6-8h (for example, 6h, 7h or 8h); the concentration of the manganese sulfate concentrate is 43-45g / ml (for example, 43g / ml, 44g / ml or 45g / ml).

[0048] In the embodiment of the present invention, the solution obtained after impurity removal and filtration is pre-concentrated under heating conditions to increase the concentration of manganese ions in the solution. In addition, during the pre-concentration process, calcium sulfate in the solution is precipitated under the common ion effect, and then the manganese sulfate concentrate is cooled. Finally, most of the calcium sulfate impurities can be removed by filter pressing the high-concentration manganese sulfate solution.

[0049] At the same time, the embodiment of the present invention controls the concentration of the manganese sulfate concentrate after pre-concentration to 43-45 g / L (according to the Mn concentration of 160-200 g / L in the solution), which is not only conducive to removing most of the calcium sulfate impurities, thereby obtaining a manganese sulfate concentrate with a high manganese content, but also conducive to the subsequent rapid acquisition of high-purity manganese sulfate powder.

[0050] According to some preferred embodiments, in step (3), the amount of sulfuric acid added is 400-600 Kg / m 3 (For example, it can be 400Kg / m 3 , 500Kg / m 3 or 600Kg / m 3 ); the reaction temperature is 20-80°C (for example, 20°C, 30°C, 40°C, 60°C or 80°C), and the reaction time is 2-3h (for example, 2h, 2.5h or 3h).

[0051] In the embodiment of the present invention, by further adding manganese sulfate concentrate to the solution at a pressure of 400-600 kg / m 3 Sulfuric acid is added to react. Since the concentration of manganese sulfate is high and the concentration of other impurity ions is low, manganese sulfate can be precipitated from the solution after adding a certain amount of sulfuric acid, while other impurities such as potassium and magnesium ions remain in the solution. After filtration, manganese sulfate powder with relatively high purity can be obtained.

[0052] At the same time, the experiment of the present invention proves that adding an appropriate amount of sulfuric acid to the manganese sulfate concentrate is conducive to obtaining manganese sulfate powder with higher yield and higher purity. If the content of sulfuric acid is too low, it is not conducive to precipitating more manganese sulfate powder from the solution. If the content of sulfuric acid is too high, other impurities such as magnesium sulfate will be precipitated, which is not conducive to ensuring the high purity of the manganese sulfate powder.

[0053] It is confirmed in the examples of the present invention that when the temperature during the acid precipitation process is relatively high, such as in the range of 46-80° C., the manganese sulfate powder has a higher yield, but the purity is relatively poor; while when the temperature is relatively low, such as in the range of 20-45° C., the yield of the manganese sulfate powder will be reduced by 5-10%, but the impurity content in the manganese sulfate powder will be lower and the purity will be higher; therefore, the temperature of the acid precipitation process can be controlled according to the actual demand for manganese sulfate powder (such as purity or yield).

[0054] According to some preferred embodiments, in step (4), the concentration of the return solution is 40-45% of the mass concentration of hydrogen peroxide, and the addition amount of the second impurity remover is 0.2-2 kg / m 3 (For example, it can be 0.2Kg / m 3 , 0.5Kg / m 3 , 1Kg / m 3 , 1.5Kg / m 3 or 2Kg / m 3 ); before adding the second impurity remover to the return solution for impurity removal, the method further comprises adding metallic manganese powder to the return solution to adjust the pH of the return solution to above 4.5.

[0055] In the embodiment of the present invention, after obtaining manganese sulfate powder, sulfuric acid is further used to dissolve the manganese sulfate powder back to obtain a certain concentration of back solution, which is beneficial to reduce the energy consumption of the subsequent crystallization process, and in order to further remove trace impurities in manganese sulfate, high-purity metallic manganese is used to adjust the pH value of the back solution to 4.5-5.0, so that other trace impurities such as trivalent iron ions can be hydrolyzed and precipitated. At the same time, adding hydrogen peroxide to the solution can oxidize iron impurities introduced by equipment or improper operation to trivalent iron ions, and then hydrolyze and precipitate in the solution of the above pH value, and a high-purity manganese sulfate solution can be obtained after filter pressing. In this way, the manganese sulfate can be secondary impurity-removed through the above operation, which is beneficial to further improve the purity of manganese sulfate.

[0056] It should be noted that, in the embodiments of the present invention, the sulfuric acid used is concentrated sulfuric acid with a concentration of 98%, and in order to avoid the introduction of impurities into the solution during the operation process or experimental equipment, the embodiments of the present invention preferably use equipment (such as plastic equipment) that is acid-resistant, high-temperature-resistant and fluorine-free.

[0057] According to some preferred embodiments, in step (5), the temperature of the heating crystallization is above 95°C (for example, it can be 95°C, 100°C, 105°C, 110°C, 115°C, 118°C or 120°C), and the concentration of the solution after heating crystallization is 53-60°C (for example, it can be 53°C, 55°C, 56°C, 58°C or 60°C).

[0058] In the embodiment of the present invention, through the above-mentioned pretreatment impurity removal, pre-concentration impurity removal and acid precipitation impurity removal processes, the manganese sulfate solution in the present invention only needs to be heated and crystallized once to obtain a high-yield, high-purity battery-grade manganese sulfate powder, thereby avoiding the problem of high energy consumption caused by multiple crystallizations.

[0059] It should be noted that before heating and crystallizing, an appropriate amount of sulfuric acid can be added to the solution before crystallization according to the pH requirements of the final battery-grade high-purity manganese sulfate powder. At the same time, in order to prevent manganese sulfate from oxidizing and discoloring under high temperature, an appropriate amount of hydrogen peroxide can be added to the solution before crystallization to adjust the color of the manganese oxide solution. At the same time, the amount of sulfuric acid and hydrogen peroxide added can be added according to actual needs.

[0060] In summary, in the embodiments of the present invention, by using sulfuric acid as the reaction system, manganese oxide ore and pyrite as raw materials, and combining a series of processes such as sulfuric acid pretreatment, heating pre-concentration, acid precipitation and re-dissolution crystallization, calcium, magnesium, potassium, sodium and other metal ions in the manganese sulfate solution can be effectively removed, and a high-yield battery-grade high-purity manganese sulfate powder can be obtained; the preparation process in the present invention is short, the acid content is high, but the acid is not consumed, and the dehydrated acid solution can be used in other processes, and the crystallization process has low energy consumption, and the energy-consuming processes are only the pre-concentration process and the final crystallization process, which has obvious cost advantages.

[0061] The embodiment of the present invention further provides a battery-grade high-purity manganese sulfate, which is prepared by any of the preparation processes described above.

[0062] In order to more clearly illustrate the technical solution and advantages of the present invention, a battery-grade high-purity manganese sulfate and its preparation process are described in detail through several embodiments below.

[0063] Embodiment 1:

[0064] (1) Add 1000 kg of Gabonese manganese oxide ore and 1000 kg of pyrite to two pickling barrels respectively, then add 30 kg of concentrated sulfuric acid to the two pickling barrels respectively, stir and mix for 1 hour, and then use a dehydrator to dehydrate; then, place the pickled Gabonese manganese oxide ore and pyrite in two water washing barrels respectively, add clean water to the water washing barrels at a liquid-to-solid ratio of 3:1, stir and wash for 1 hour, and obtain the pre-treated Gabonese manganese oxide ore and pyrite after dehydration; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0065] (2) adding the pretreated Gabonese manganese oxide ore and pyrite into a reaction barrel, adding clean water into the reaction barrel at a liquid-to-solid ratio of 3:1, mixing well, then adding sulfuric acid, stirring and mixing well, then adding steam to a temperature of 85° C. and reacting for 6 hours; wherein the content of sulfuric acid is 0.55 times the content of the Gabonese manganese oxide ore;

[0066] After the reaction reaches the end point, first add a neutralizer (calcium oxide) to the reaction system to adjust the pH value of the reaction system to 5.0, then add the first impurity remover, industrial barium sulfide 5Kg / m 3 and 1 kg / m3 of hydrogen peroxide with a mass concentration of 30% 3After impurities are removed and filtered, a manganese sulfate solution is obtained; wherein the mass of the pyrite is 30% of the mass of the Gabonese manganese oxide ore; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0067] (3) The manganese sulfate solution obtained after impurity removal is pumped into a pre-concentration barrel, and steam is turned on to 85° C. for heating and pre-concentration until the concentration of the solution reaches 45 ppm, and then the concentration is stopped; the solution is discharged into a cooling barrel for static cooling, stirred to cool, and then allowed to stand for cooling, and finally filtered to obtain a manganese sulfate concentrate; the dehydrated mother liquor is pumped into a collection tank for secondary utilization;

[0068] (4) Send the manganese sulfate concentrate to the acid precipitation tank at 500 kg / m 3 Add sulfuric acid in an amount of 1000 mg / L to the acid precipitation barrel, control the system temperature at 25°C to react for 2 hours, and then dehydrate to obtain manganese sulfate powder; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0069] (5) Place manganese sulfate powder in a neutralization barrel, add sulfuric acid to the neutralization barrel for re-dissolution, so that the concentration of the re-solution is 42%, add high-purity metallic manganese powder to the re-solution to neutralize the pH value of the re-solution to 5.0, and then add the second impurity remover (hydrogen peroxide with a mass concentration of 30%) 1 kg / m 3 Perform secondary impurity removal and obtain a manganese sulfate solution after filter pressing;

[0070] (6) According to actual needs, sulfuric acid is added to the manganese sulfate solution in step (5) to adjust the pH value to 2.8-3.5, and then hydrogen peroxide (1 kg / m 3 ) Adjust the color of the solution, then open the steam to 110°C for evaporation and crystallization, stop after crystallization reaches 60°C, dry the sample after dehydration, and collect the dehydrated mother liquor for secondary utilization to obtain battery-grade high-purity manganese sulfate powder.

[0071] During the experiment, the solution components in each step of Example 1 were detected using an inductively coupled plasma spectrometer. The detection results are shown in Table 1.

[0072] Embodiment 2:

[0073] (1) Add 1000 kg of Gabonese manganese oxide ore and 1000 kg of pyrite to two pickling barrels respectively, then add 100 kg of concentrated sulfuric acid to the two pickling barrels respectively, stir and mix for 1 hour, and then use a dehydrator to dehydrate; then, place the pickled Gabonese manganese oxide ore and pyrite in two water washing barrels respectively, add clean water to the water washing barrels at a liquid-to-solid ratio of 3:1, stir and wash for 1 hour, and obtain the pre-treated Gabonese manganese oxide ore and pyrite after dehydration; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0074] (2) adding the pretreated Gabonese manganese oxide ore and pyrite into a reaction barrel, adding clean water into the reaction barrel at a liquid-to-solid ratio of 3:1, mixing well, then adding sulfuric acid, stirring and mixing well, then adding steam to a temperature of 90° C. and reacting for 6 hours; wherein the content of sulfuric acid is 0.45 times the content of the Gabonese manganese oxide ore;

[0075] After the reaction reaches the end point, first add a neutralizer (calcium oxide) to the reaction system to adjust the pH value of the reaction system to 5.0, then add the first impurity remover, industrial barium sulfide 7Kg / m 3 and 2 kg / m3 of hydrogen peroxide with a mass concentration of 30% 3 After impurities are removed and filtered, a manganese sulfate solution is obtained; wherein the mass of the pyrite is 25% of the mass of the Gabonese manganese oxide ore; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0076] (3) The manganese sulfate solution obtained after impurity removal is pumped into a pre-concentration barrel, and steam is turned on to 90° C. for heating and pre-concentration until the concentration of the solution is 43 ppm, and then the concentration is stopped; the solution is discharged into a cooling barrel for static cooling, stirred to cool, and then allowed to stand for cooling, and finally filtered to obtain a manganese sulfate concentrate; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0077] (4) Send the manganese sulfate concentrate to the acid precipitation tank at 600 kg / m 3 Add sulfuric acid in an amount of 1000 mg / L to the acid precipitation barrel, control the system temperature at 25°C to react for 2 hours, and then dehydrate to obtain manganese sulfate powder; the dehydrated mother liquor is pumped into a collection pool for secondary utilization;

[0078] (5) Place manganese sulfate powder in a neutralization barrel, add sulfuric acid to the neutralization barrel for re-dissolution, so that the concentration of the re-solution is 42%, add high-purity metallic manganese powder to the re-solution to neutralize the pH value of the re-solution to 5.0, and then add the second impurity remover (hydrogen peroxide with a mass concentration of 30%) to the re-solution. 3 Perform secondary impurity removal and obtain a manganese sulfate solution after filter pressing;

[0079] (6) According to actual needs, sulfuric acid is added to the manganese sulfate solution in step (5) to adjust the pH value to 2.8-3.5, and then hydrogen peroxide (1 kg / m 3 ) Adjust the color of the solution, then open the steam to 120°C for evaporation and crystallization, stop when the crystallization reaches 55°C, dry the sample after dehydration, and the dehydrated mother liquor enters the collection pool for secondary utilization to obtain battery-grade high-purity manganese sulfate powder.

[0080] Embodiment 3:

[0081] Example 3 is basically the same as Example 1, except that in step (1), during the pickling process, the content of sulfuric acid is 25 kg.

[0082] Embodiment 4:

[0083] Example 4 is substantially the same as Example 1, except that in step (3), the concentration of the manganese sulfate concentrate is 40 ppm.

[0084] Embodiment 5:

[0085] Example 5 is basically the same as Example 1, except that in step (4), the 3 Add sulfuric acid in the acid precipitation tank.

[0086] Comparative Example 1:

[0087] Comparative Example 1 is substantially the same as Example 1, except that the pretreatment process in step (1) is omitted, that is, the Gabonese manganese oxide ore and pyrite are directly added to the reaction barrel to react with sulfuric acid.

[0088] Comparative Example 2:

[0089] Comparative Example 2 is substantially the same as Example 1, except that the neutralization and impurity removal step in step (2) is removed, that is, the pretreated Gabonese manganese oxide ore and pyrite are reacted with sulfuric acid and then directly sent to the pre-concentration barrel for pre-concentration.

[0090] Comparative Example 3:

[0091] Comparative Example 3 is substantially the same as Example 1, except that step (3) is omitted, that is, the manganese sulfate solution obtained after impurity removal in step (2) is directly sent to the acid precipitation tank for acid precipitation.

[0092] Comparative Example 4:

[0093] Comparative Example 4 is substantially the same as Example 1, except that step (4) is omitted, that is, the manganese sulfate concentrate obtained in step (3) is directly heated and crystallized.

[0094] The components in the high-purity manganese sulfate powders (hereinafter referred to as samples) prepared in Examples 2 to 5 and Comparative Examples 1 to 4 were detected using an inductively coupled plasma spectrometer. The detection results are shown in Table 5.

[0095] Table 1 Average test results before and after pre-concentration

[0096]

[0097] The effect of pre-concentration and impurity removal was investigated by obtaining average values ​​from multiple groups of data. It can be seen from Table 1 that after pre-concentration treatment, the Mn concentration increased to about 195 g / L on average, the Ca concentration decreased significantly from 628 mg / L to about 230 mg / L, the Mg content was lower than 300 mg / L, and the content of other impurities was lower than 20 mg / L.

[0098] Table 2 Detection results of sample components after acid precipitation

[0099]

[0100]

[0101] As can be seen from Table 2, compared with Table 1, the contents of Ca, Mg and H2SO4 in multiple batches of products obtained after acid precipitation and dehydration were reduced and relatively stable, with average values ​​of Ca: 50ppm; Mg: 63.21ppm, H2SO4: 3.68%, among which the contents of Ca and Mg decreased most significantly.

[0102] Table 3 Detection results of sample solution after re-dissolution, neutralization and impurity removal

[0103]

[0104] It can be seen from Table 3 that after re-dissolution and impurity removal, the Ca content of multiple batches of solutions is lower than 30 mg / L, and the Mg content is lower than 40 mg / L, which creates conditions for crystallization to obtain low-content Ca and Mg battery-grade high-purity manganese sulfate products.

[0105] Table 4 Test results of samples after crystallization

[0106]

[0107] It can be seen from Table 4 that after heating and crystallizing the low Ca and Mg content solution obtained after re-dissolution, neutralization and impurity removal, the Ca and Mg contents in the obtained battery-grade high-purity manganese sulfate product are less than 30 ppm, and multiple batches of products are obtained continuously, and the samples have good reproducibility.

[0108] Table 5

[0109]

[0110] It can be seen from Table 5 that, compared with the comparative example, the manganese sulfate product prepared in the embodiment of the present invention has the advantages of high purity, low energy consumption, low cost and high yield.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for preparing battery-grade high-purity manganese sulfate, characterized in that: The preparation process comprises the following steps: (1) adding manganese oxide ore and pyrite to water and mixing them evenly, then adding sulfuric acid to react, and after the reaction reaches an end point, adding a first impurity remover to the reaction system to remove impurities, and filtering to obtain a manganese sulfate solution; (2) heating the manganese sulfate solution for pre-concentration to obtain a manganese sulfate concentrated solution; (3) adding sulfuric acid to the manganese sulfate concentrate to react, and obtaining manganese sulfate powder after dehydration; (4) after re-dissolving the manganese sulfate powder with water, adding a second impurity remover to the re-dissolved solution to remove impurities; (5) The impurity-removed solution is heated and crystallized, and the battery-grade high-purity manganese sulfate powder is obtained after dehydration.

2. The preparation process according to claim 1, characterized in that: Before step (1), the method further comprises the steps of acid washing and water washing the manganese oxide ore and the pyrite ore respectively; Preferably, during the pickling process, the content of sulfuric acid is 3-10% of the content of the manganese oxide ore or pyrite, and during the water washing process, the mass ratio of water content to the Gabonese oxide ore or pyrite is (2-3):

1.

3. The preparation process according to claim 1, characterized in that: In step (1), the content of pyrite is 25-30% of the content of manganese oxide ore, the mass ratio of the total amount of pyrite and manganese oxide ore to water is 1:(2-3), and the content of sulfuric acid is 0.42-0.55 times the content of manganese oxide ore; and / or In step (1), the reaction temperature is 85-90°C and the reaction time is 6-8h.

4. The preparation process according to claim 1, characterized in that: In step (1), before adding the first impurity remover to the reaction system for impurity removal, the method further comprises adding a neutralizing agent to the reaction system to adjust the pH value to above 5.0; preferably, the neutralizing agent is calcium oxide.

5. The preparation process according to claim 1 or 4, characterized in that: In step (1), the first impurity remover comprises barium sulfide and hydrogen peroxide; preferably, the addition amount of the barium sulfide is 3-7 kg / m 3 The amount of hydrogen peroxide added is 0.2-2kg / m 3 .

6. The preparation process according to claim 1, characterized in that: In step (2), the heating temperature is 85-90°C and the heating time is 6-8h; and / or The concentration of the manganese sulfate concentrate is 43-45 wt%.

7. The preparation process according to claim 1, characterized in that: In step (3), the amount of sulfuric acid added is 400-600 kg / m 3 ; and / or In step (3), the reaction temperature is 20-80°C and the reaction time is 2-3h.

8. The preparation process according to claim 1, characterized in that: In step (4), the concentration of the return solution is 40-45% and the second impurity remover is hydrogen peroxide. The addition amount of the second impurity remover is 0.2-2 kg / m 3 ; and / or Before adding the second impurity remover to the return solution for impurity removal, the method further includes adding metal manganese powder to the return solution to adjust the pH value of the return solution to above 4.

5.

9. The preparation process according to claim 1, characterized in that: In step (5), the temperature of the heating crystallization is above 95°C, and the concentration of the solution after heating crystallization is 53-60%.

10. A battery-grade high-purity manganese sulfate, characterized in that: The method is prepared by the preparation process described in any one of claims 1 to 9.

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