Method for clean production of manganous-manganic oxide

Abstract

The invention discloses a method for cleanly producing manganous-manganic oxide, which comprises the following steps: purifying pyrolusite leachate, adding water for dilution to prepare a manganese sulfate solution with the concentration of 0.6-1.5 mol / L, slowly adding ammonia water with the mass fraction of 10-25% into the manganese sulfate solution, and simultaneously stirring to control the pH value of the solution at the end point to be 8.5-11; adding ammonia water, introducing air and assisting microwave treatment to oxidize, stopping adding the ammonia water, continuously stirring for 2-3 hours, cooling the solution to room temperature, filtering, and washing a filter cake with deionized water to obtain the manganous-manganic oxide; and heating and drying the manganous-manganic oxide, and cooling to obtain the high-purity manganous-manganic oxide. The method is simple to operate and low in production cost, and the produced manganous-manganic oxide is high in purity and large in specific surface area.

Description

Technical Field

[0001] The invention belongs to the technical field of battery materials, and particularly relates to a method for cleanly producing manganese manganese tetroxide. Background Art

[0002] After continuous improvement and development, lithium-ion batteries can provide stable current and voltage at any time, and the batteries are convenient, fast, safe and reliable to use, and have been widely used in daily life. Among the many types of batteries, lithium-ion batteries and aqueous zinc-ion batteries have great advantages and are considered to be green batteries with bright prospects.

[0003] For lithium-ion batteries, developing electrode materials with stable structure and excellent electrochemical performance is the goal of researchers. Among them, manganese-based oxides, especially MnO2, have attracted widespread attention due to their rich storage capacity, low pollution, high discharge voltage and large specific capacity. The research and progress of MnO2 has aroused people's strong interest in other manganese-based oxides such as Mn3O4. However, Mn3O4 will have a series of problems in the charge and discharge process, such as Mn 2+ Dissolution will occur, the volume changes greatly, the conductivity is low, and the redox kinetics are slow, resulting in unstable structure, fast capacity decay, low specific capacity, and poor rate performance, which seriously limits the practical application of Mn3O4. At the same time, the existing Mn3O4 preparation process also has some problems, such as heat control and reaction conditions are difficult to control, a lot of manganese dioxide and manganese trioxide are mixed in the product, the conversion rate of manganese tetraoxide is not high, and the specific surface area is small, which makes it difficult for the product to meet the needs of the development of the electronics industry and the new energy industry. Summary of the invention

[0004] Aiming at the defect that the product of the prior art process for preparing trimanganese tetraoxide is mixed with many inclusions, resulting in a low conversion rate of trimanganese tetraoxide, the present invention provides a method for cleanly producing trimanganese tetraoxide, which has simple operation, low production cost, and the produced trimanganese tetraoxide has high purity and large specific surface area.

[0005] The present invention is achieved through the following technical solutions: A method for cleanly producing manganese tetraoxide comprises the following steps: S1: purifying the pyrolusite leaching solution and diluting it with water to prepare a 0.6-1.5 mol / L manganese sulfate solution; S2: Slowly add 10% to 25% ammonia water to the manganese sulfate solution while stirring, control the ammonia water drop rate to 2.5 mL / min to 4.5 mL / min, and control the solution endpoint pH value to 8.5 to 11; S3: while adding ammonia water, introducing air for oxidation, and placing the mixed solution in a microwave for reaction; the microwave power is 800-900 W, the reaction temperature is 80-140° C., and the microwave irradiation time is 30-60 min; S4: After stopping the addition of ammonia water, continue stirring for 2 to 3 hours, filter the solution after cooling to room temperature, and wash the filter cake with deionized water. The filter cake is the manganese tetraoxide precursor; S5: heating and drying the trimanganese tetraoxide precursor, and obtaining high-purity trimanganese tetraoxide after cooling.

[0006] As a further improvement of the present invention, the purification method of the pyrolusite leaching solution in step S1 is as follows: Q1: Add ammonia water to the pyrolusite leaching solution to adjust the pH to 4-5, react for 1-2 hours, and then filter to obtain filtrate A; Q2: Heat the filtrate A to 50-60°C, add ammonium sulfide solid at 1.0-1.5 g / L, stir and react for 1-2 hours, then add polyacrylamide flocculant at 1-1.2 g / L, continue stirring and reacting for 1-2 hours, then let stand for 6-10 hours, and filter to obtain filtrate B; Q3: Heat the filtrate B to 50-55°C, then add ammonium fluoride solid at 1.6-2 g / L, stir and react for 1-2 hours, and filter to obtain the purified pyrolusite leaching solution.

[0007] As a further improvement of the present invention, the washing liquid produced in step S4 is added with a precipitant and a flocculant to react for 24 to 48 hours and then filtered, the filter residue is sent to step S1 for dissolution to prepare a manganese sulfate solution, and the filtrate is sent to evaporation and crystallization, and after drying, it is sent to the downstream process to produce by-products; The precipitant is one or a combination of ammonium sulfide, sodium hydroxide, sodium carbonate, ammonia water, ammonium bicarbonate, and sodium bicarbonate; The flocculant is one or a combination of polyacrylamide, sodium polyacrylate, polyethyleneimine, polydimethyldiallylammonium chloride and polyacrylamide.

[0008] As a further improvement of the present invention, in step S2, 4 g / L to 6 g / L of ammonium chloride is added to the manganese sulfate solution as a reaction catalyst.

[0009] As a further improvement of the present invention, in step S2, 10 to 20 ml of ethanol and 10 to 15 ml of ethylene dichloride are added to the solution as a mixed dispersant.

[0010] As a further improvement of the present invention, step S5 uses a flash dryer for heating and drying, with an inlet temperature of 200-300°C, an outlet temperature of 100-120°C, a negative pressure of 500-1000Pa, and a crushing and stirring speed of 100-150r / min.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The method of the present invention is simple to operate, has low production cost, and the produced manganese tetraoxide has high purity and large specific surface area. The product can reach the following technical indicators: Mn ≥ 71%, Si ≤ 20ppm, Ca ≤ 50ppm, Mg ≤ 50ppm, Se ≤ 5ppm, and the contents of other components are in accordance with GB / T21836-2008; specific surface area BET ≥ 10m 2 / g. DETAILED DESCRIPTION

[0012] The present invention is further described below with reference to the embodiments. In the embodiments, unless otherwise specified, the technical means used are all conventional technical means in the art. Example 1

[0013] A method for cleanly producing manganese tetraoxide comprises the following steps: S1: purifying the pyrolusite leaching solution and diluting it with water to prepare a 0.6 mol / L manganese sulfate solution; The purification method of pyrolusite leaching solution is as follows: Q1: Add ammonia water to the pyrolusite leaching solution to adjust the pH to 4, react for 1 hour and filter to obtain filtrate A; Q2: Filtrate A was heated to 50°C, and 1.0 g / L of ammonium sulfide solid was added, stirred for 1 hour, and then 1 g / L of polyacrylamide flocculant was added, and the stirring reaction was continued for 1 hour, and then allowed to stand for 6 hours, and filtered to obtain filtrate B; Q3: Heat the filtrate B to 50°C, then add ammonium fluoride solid at 1.6 g / L, stir and react for 1 hour, and filter to obtain the purified pyrolusite leaching solution.

[0014] S2: Slowly add 10% ammonia water by mass to the manganese sulfate solution while stirring, control the dropping rate of the ammonia water to 2.5 ml / min, and control the end point pH value of the solution to 8.5; at the same time, add 4 g / L ammonium chloride as a reaction catalyst to the manganese sulfate solution, add 10 ml of ethanol as a dispersant, and add 10 ml of ethanol and 10 ml of dichloroethane as a mixed dispersant.

[0015] S3: while adding ammonia water, introducing air for oxidation, and placing the mixed solution in a microwave for reaction; the microwave power is 800 W, the reaction temperature is 140° C., and the microwave irradiation time is 60 min.

[0016] S4: After stopping the addition of ammonia water, continue stirring for 2 hours, filter the solution after cooling to room temperature, and wash the filter cake with deionized water. The filter cake is the manganese tetraoxide precursor.

[0017] S5: Use a flash dryer for heating and drying, with an inlet temperature of 200°C, an outlet temperature of 100°C, a negative pressure of 500Pa, and a crushing and stirring speed of 100r / min. After cooling, high-purity manganese tetraoxide is obtained. Example 2

[0018] A method for cleanly producing manganese tetraoxide comprises the following steps: S1: purifying the pyrolusite leaching solution and diluting it with water to prepare a 1.5 mol / L manganese sulfate solution; The purification method of pyrolusite leaching solution is as follows: Q1: Add ammonia water to the pyrolusite leaching solution to adjust the pH to 5, react for 2 hours and then filter to obtain filtrate A; Q2: Heat the filtrate A to 60°C, add 1.5 g / L of ammonium sulfide solid, stir for 2 hours, then add 1.2 g / L of polyacrylamide flocculant, continue stirring for 2 hours, then let stand for 10 hours, and filter to obtain filtrate B; Q3: Heat the filtrate B to 55°C, then add 2 g / L of solid ammonium fluoride, stir and react for 2 hours, and filter to obtain the purified pyrolusite leaching solution.

[0019] S2: Slowly add 25% ammonia water by mass to the manganese sulfate solution while stirring, control the dropping rate of the ammonia water to 4.5 ml / min, and control the end point pH value of the solution to 11; at the same time, add 6 g / L ammonium chloride as a reaction catalyst to the manganese sulfate solution, add 20 ml of ethanol as a dispersant, and add 20 ml of ethanol and 15 ml of dichloroethane as a mixed dispersant.

[0020] S3: while adding ammonia water, introducing air for oxidation, and placing the mixed solution in a microwave for reaction; the microwave power is 800-900 W, the reaction temperature is 80-140° C., and the microwave radiation time is 30-60 min.

[0021] S4: After stopping the addition of ammonia water, continue stirring for 3 hours, filter the solution after cooling to room temperature, and wash the filter cake with deionized water. The filter cake is the manganese tetraoxide precursor; add ammonium sulfide precipitant and polyacrylamide flocculant to the generated washing liquid, let it stand for 48 hours and then filter it, send the filter residue to step S1 for dissolution to prepare manganese sulfate solution, send the filtrate to evaporation crystallization, and send it to the downstream process to produce by-products after drying; S5: Use a flash dryer for heating and drying, with an inlet temperature of 200-300°C, an outlet temperature of 100-120°C, a negative pressure of 500-1000Pa, a crushing and stirring speed of 100-150r / min, and high-purity manganese tetraoxide is obtained after cooling. Example 3

[0022] A method for cleanly producing manganese tetraoxide comprises the following steps: S1: purifying the pyrolusite leaching solution and diluting it with water to prepare a 1.2 mol / L manganese sulfate solution; The purification method of pyrolusite leaching solution is as follows: Q1: Add ammonia water to the pyrolusite leaching solution to adjust the pH to 5, react for 2 hours and then filter to obtain filtrate A; Q2: Filtrate A was heated to 55°C, and solid ammonium sulfide was added at 1.2 g / L, stirred for 1 hour, and then polyacrylamide flocculant was added at 1.1 g / L, and the stirring reaction was continued for 1 hour, and then allowed to stand for 8 hours, and filtered to obtain filtrate B; Q3: Heat the filtrate B to 52°C, then add ammonium fluoride solid at 1.8 g / L, stir and react for 2 hours, and filter to obtain the purified pyrolusite leaching solution.

[0023] S2: Slowly add 20% ammonia water by mass to the manganese sulfate solution while stirring, control the dropping rate of the ammonia water to 3.0 ml / min, and control the end point pH value of the solution to 9.5; at the same time, add 5 g / L ammonium chloride as a reaction catalyst to the manganese sulfate solution, add 15 ml of ethanol as a dispersant, and add 15 ml of ethanol and 12 ml of dichloroethane as a mixed dispersant.

[0024] S3: while adding ammonia water, introducing air for oxidation, and placing the mixed solution in a microwave for reaction; the microwave power is 800-900 W, the reaction temperature is 80-140° C., and the microwave radiation time is 30-60 min.

[0025] S4: After stopping the addition of ammonia water, continue stirring for 3 hours, filter the solution after cooling to room temperature, and wash the filter cake with deionized water. The filter cake is the manganese tetraoxide precursor; sodium hydroxide, sodium carbonate precipitant, sodium polyacrylate, and polyacrylamide flocculant are added to the generated washing liquid to react for 24 hours and then filtered. The filter residue is sent to step S1 for dissolution to prepare a manganese sulfate solution, and the filtrate is sent to evaporation and crystallization, and after drying, it is sent to the downstream process to produce by-products.

[0026] S5: Use a flash dryer for heating and drying, with an inlet temperature of 200-300°C, an outlet temperature of 100-120°C, a negative pressure of 500-1000Pa, a crushing and stirring speed of 100-150r / min, and high-purity manganese tetraoxide is obtained after cooling.

[0027] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A method for clean production of manganese tetraoxide, characterized in that: The following steps are involved: S1: purifying the pyrolusite leaching solution and diluting it with water to prepare a 0.6-1.5 mol / L manganese sulfate solution; S2: Slowly add 10% to 25% ammonia water to the manganese sulfate solution while stirring, control the ammonia water drop rate to 2.5 mL / min to 4.5 mL / min, and control the solution endpoint pH value to 8.5 to 11; S3: while adding ammonia water, introducing air for oxidation, and placing the mixed solution in a microwave for reaction; the microwave power is 800-900 W, the reaction temperature is 80-140° C., and the microwave irradiation time is 30-60 min; S4: After stopping the addition of ammonia water, continue stirring for 2 to 3 hours, filter the solution after cooling to room temperature, and wash the filter cake with deionized water. The filter cake is the manganese tetraoxide precursor; S5: heating and drying the trimanganese tetraoxide precursor, and obtaining high-purity trimanganese tetraoxide after cooling.

2. A method for clean production of manganese tetraoxide according to claim 1, characterized in that: The purification method of the pyrolusite leaching solution in step S1 is as follows: Q1: Add ammonia water to the pyrolusite leaching solution to adjust the pH to 4-5, react for 1-2 hours, and then filter to obtain filtrate A; Q2: Heat the filtrate A to 50-60°C, add ammonium sulfide solid at 1.0-1.5 g / L, stir and react for 1-2 hours, then add polyacrylamide flocculant at 1-1.2 g / L, continue stirring and reacting for 1-2 hours, then let stand for 6-10 hours, and filter to obtain filtrate B; Q3: Heat the filtrate B to 50-55°C, then add ammonium fluoride solid at 1.6-2 g / L, stir and react for 1-2 hours, and filter to obtain the purified pyrolusite leaching solution.

3. A method for clean production of manganese tetraoxide according to claim 1, characterized in that: The washing liquid produced in step S4 is added with a precipitant and a flocculant to react for 24 to 48 hours and then filtered. The filter residue is sent to step S1 for dissolution to prepare a manganese sulfate solution, and the filtrate is sent to evaporation and crystallization, and after drying, it is sent to the downstream process to produce by-products; The precipitant is one or a combination of ammonium sulfide, sodium hydroxide, sodium carbonate, ammonia water, ammonium bicarbonate, and sodium bicarbonate; The flocculant is one or a combination of polyacrylamide, sodium polyacrylate, polyethyleneimine, polydimethyldiallylammonium chloride and polyacrylamide.

4. A method for clean production of manganese tetraoxide according to claim 1, characterized in that: In step S2, 4 g / L to 6 g / L of ammonium chloride is added to the manganese sulfate solution as a reaction catalyst.

5. The method for clean production of manganese tetraoxide according to claim 1, characterized in that: In step S2, 10 to 20 mL of ethanol and 10 to 15 mL of ethylene dichloride are added to the solution as a mixed dispersant.

6. The method for clean production of manganese tetraoxide according to claim 1, characterized in that: The step S5 adopts a flash dryer for heating and drying, with an inlet temperature of 200-300° C., an outlet temperature of 100-120° C., a negative pressure of 500-1000 Pa, and a crushing and stirring speed of 100-150 r / min.