阅读说明：本技术 一种低成本高容量锰酸锂前驱体的制备方法 (Preparation method of low-cost high-capacity lithium manganate precursor ) 是由 曹栋强 许泽辉 屈建高 黄飞中 方明 邱颖 罗瑞平 王从泽 任红霞 于 2021-01-25 设计创作，主要内容包括：本发明涉及锰酸锂前驱体制备技术领域,具体而言,涉及一种低成本高容量锰酸锂前驱体材料及其改性制备方法。本发明一种低成本高容量锰酸锂前驱体的制备方法,包括如下步骤：(1)原料的选择；(2)原料的处理；(3)溶液除杂；(4)分离液PH值和温度调节；(5)分离液中Mn2+氧化；(6)沉淀并掺杂包覆；(7)反应合成与分离；(8)四氧化三锰的干燥包装。本发明提供了一种低成本、高性能、结构稳定、掺杂包覆改性的锰酸锂前驱体----四氧化三锰的制备方法。(The invention relates to the technical field of lithium manganate precursor preparation, in particular to a low-cost high-capacity lithium manganate precursor material and a modified preparation method thereof. The invention relates to a preparation method of a low-cost high-capacity lithium manganate precursor, which comprises the following steps: (1) selecting raw materials; (2) processing raw materials; (3) removing impurities from the solution; (4) adjusting the pH value and the temperature of the separation solution; (5) oxidizing Mn2+ in the separation liquid; (6) precipitating, doping and coating; (7) reaction synthesis and separation; (8) and (5) drying and packaging the manganous-manganic oxide. The invention provides a preparation method of doped, coated and modified lithium manganate precursor-manganous oxide, which has the advantages of low cost, high performance, stable structure and doping.)

1. A preparation method of a low-cost high-capacity lithium manganate precursor is characterized by comprising the following steps:

selection of raw materials

Selecting waste manganese liquid or waste manganese slag;

(2) treatment of raw materials

Carrying out acidity adjustment and dissolution on the waste manganese liquid or the waste manganese slag, and adjusting the pH value of the solution to 2.5-3.5;

(3) removing impurities from solution

Firstly, adding polyalcohol amine cationic surfactant into solution in a reactor according to the proportion of 0.2-0.4 g/L, adding precipitator A into the solution according to the metering ratio according to the content of different impurities in the solution in a reaction container, stirring for 30-60 minutes at a set rotating speed, standing for 60 minutes, separating, and performing next-step impurity removal on separated liquid;

secondly, removing impurities, namely adding a precipitator B into the separation liquid according to the characteristics of impurity ions in the separation liquid, stirring for 30-60 minutes at a set rotating speed, standing for 60 minutes, separating, and allowing the separation liquid to enter the next working procedure;

(4) pH and temperature control of the separation liquid

Firstly, introducing polyalcohol nonionic surfactant into a separation solution at a ratio of 0.2-0.4 g/l, and adjusting the pH value of the separation solution to 7-10 by adopting 25-30% alkaline solution; simultaneously, heating to 50-70 ℃ for constant-temperature reaction;

(5) oxidation of Mn2+ in the separated liquid

Introducing an oxidant according to the content of Mn2+ in the separation liquid and the amount of Mn4+ required for preparing manganous-manganic oxide, measuring a certain amount of hydrogen peroxide, slowly adding the separation liquid into a reaction container at a set speed when the pH value of the separation liquid is more than or equal to 6.5, slowly dropping 25-30% of alkaline solution while carrying out oxidation reaction, keeping the pH value of the solution between 6.5 and 7, and stirring at a set rotating speed;

(6) precipitating and doping coating

Along with the adjustment of the pH value of the separation liquid and the oxidation reaction, the precipitation of the manganous-manganic oxide begins; after the pH value of the solution is adjusted to a set value, introducing a dopable coating element source X according to 0.4-1.0% of the theoretical synthesis amount of the manganous-manganic oxide;

(7) reaction synthesis and separation

After the doped coating element source is introduced, continuously stirring at constant temperature for reaction for 120 minutes, stopping heating, and then separating and washing; the separated solid phase enters the next drying procedure, and the separated liquid enters an MVR system for purification and reuse;

(8) dry package of mangano-manganic oxide

And separating the solid phase, drying at the drying temperature of 100-160 ℃ for 6 hours, crushing, sieving, demagnetizing and packaging to obtain the finished product.

2. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: the acid used for acidity adjustment and dissolution in the step (2) is sulfuric acid.

3. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: and (3) the alkaline solution in the steps (4) and (5) is sodium hydroxide or ammonia water.

4. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: the oxidant in the step (5) is hydrogen peroxide.

5. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: and (3) the coating element source X in the step (6) is an oxide or chloride or hydroxide of Cr, Al, Mg and Nb elements.

6. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: the precipitator A is manganese sulfate.

7. The method for preparing a low-cost high-capacity lithium manganate precursor according to claim 1, wherein: the precipitant B is sodium sulfide.

Technical Field

The invention relates to the technical field of lithium manganate precursor preparation, in particular to a low-cost high-capacity lithium manganate precursor material and a modified preparation method thereof.

Technical Field

At present, the market of the cobalt salt industry is well developed under the drive of the new energy industry, but the treatment of waste manganese liquid caused by the preparation of cobalt salt always troubles cobalt salt manufacturers (the waste manganese liquid is treated with negative value at present). About 21000 million liters of waste liquid is produced according to 14 million tons of annual supply and demand of cobalt salt in the current market, and about 1.5 to 2 million tons of manganese metal is produced according to the manganese content in the waste liquid. Theoretically, there is an amount of about 2 to 2.7 ten thousand tons in terms of manganomanganic oxide.

Lithium manganate is taken as a lithium battery positive electrode material and is always favored by people in the small lithium battery industry due to low cost and high safety; at present, the market application of lithium manganate is more and more extensive due to the development of dynamic manganese and the continuous improvement of the cycle performance thereof. The manganous-manganic oxide is an important manganese source precursor for manufacturing the dynamic lithium manganate with high capacity and high cycle performance. However, at present, the main manufacturers in the manganese source market (Guizhou Hongxing, Hunan Tan electrochemical, Yunan Guiliu and Guangxi Huiyuan) in China do not have the technology for preparing the trimanganese tetroxide; the manufacturers really put on the market and producing the manganomanganic oxide in batches only have the natural source of steel in Anhui province. The manganomanganic oxide project synthesized by Darongyuan in Guizhou is also in active production expansion, but because of the technical process limitation of the preparation, the manganomanganic oxide product has high selling price (1.3-1.6 ten thousand/ton) and no market advantage.

Disclosure of Invention

The invention aims to provide a preparation method of doped, coated and modified lithium manganate precursor-manganous oxide with low cost, high performance and stable structure, and the specific scheme is as follows:

a preparation method of a low-cost high-capacity lithium manganate precursor comprises the following steps:

(1) selection of raw materials

Selecting waste manganese liquid or waste manganese slag;

(2) treatment of raw materials

Carrying out acidity adjustment and dissolution on the waste manganese liquid or the waste manganese slag, and adjusting the pH value of the solution to 2.5-3.5;

(3) removing impurities from solution

Firstly, adding polyalcohol amine cationic surfactant into solution in a reactor according to the proportion of 0.2-0.4 g/L, adding precipitator A into the solution according to the metering ratio according to the content of different impurities in the solution in a reaction container, stirring for 30-60 minutes at a set rotating speed, standing for 60 minutes, separating, and performing next-step impurity removal on separated liquid;

secondly, removing impurities, namely adding a precipitator B into the separation liquid according to the characteristics of impurity ions in the separation liquid, stirring for 30-60 minutes at a set rotating speed, standing for 60 minutes, separating, and allowing the separation liquid to enter the next working procedure;

(4) pH and temperature control of the separation liquid

Firstly, introducing polyalcohol nonionic surfactant into a separation solution at a ratio of 0.2-0.4 g/l, and adjusting the pH value of the separation solution to 7-10 by adopting 25-30% alkaline solution; simultaneously, heating to 50-70 ℃ for constant-temperature reaction;

(5) oxidation of Mn2+ in the separated liquid

Introducing an oxidant according to the content of Mn2+ in the separation liquid and the amount of Mn4+ required for preparing manganous-manganic oxide, measuring a certain amount of hydrogen peroxide, slowly adding the separation liquid into a reaction container at a set speed when the pH value of the separation liquid is more than or equal to 6.5, slowly dropping 25-30% of alkaline solution while carrying out oxidation reaction, keeping the pH value of the solution between 6.5 and 7, and stirring at a set rotating speed;

(6) precipitating and doping coating

Along with the adjustment of the pH value of the separation liquid and the oxidation reaction, the precipitation of the manganous-manganic oxide begins; after the pH value of the solution is adjusted to a set value, introducing a dopable coating element source X according to 0.4-1.0% of the theoretical synthesis amount of the manganous-manganic oxide;

(7) reaction synthesis and separation

After the doped coating element source is introduced, continuously stirring at constant temperature for reaction for 120 minutes, stopping heating, and then separating and washing; the separated solid phase enters the next drying procedure, and the separated liquid enters an MVR system for purification and reuse;

(8) dry package of mangano-manganic oxide

And separating the solid phase, drying at the drying temperature of 100-160 ℃ for 6 hours, crushing, sieving, demagnetizing and packaging to obtain the finished product.

The acid used for acidity adjustment and dissolution in the step (2) is sulfuric acid.

And (3) the alkaline solution in the steps (4) and (5) is sodium hydroxide or ammonia water.

The oxidant in the step (5) is hydrogen peroxide.

And (3) the coating element source X in the step (6) is an oxide or chloride or hydroxide of Cr, Al, Mg and Nb elements.

The precipitator A is manganese sulfate.

The precipitant B is sodium sulfide.

The innovation points of the invention are as follows: (1) the adopted raw materials are industrial waste materials, and the raw materials are cobalt salt waste liquid or waste residue, so that the cost is very low, and a feasible method is provided for the treatment of the waste liquid and the waste residue of a cobalt salt manufacturer; (2) in the preparation process, the preparation of the material is modified by adopting a surfactant (agglomeration of material precipitates and impurity inclusion are reduced, and the purity and yield of the prepared material are improved); (3) different doped coating element sources are introduced in the precipitation preparation link for modification, so that the phenomenon of uneven mixing of the doped coating element sources introduced in the lithium manganate preparation is avoided.

Drawings

FIG. 1 is a particle size distribution diagram of the manganomanganic oxide material synthesized in example 1;

FIG. 2 is a graph showing the particle size distribution of a lithium manganate material prepared from manganomanganic oxide of example 1;

FIG. 3 is an electron micrograph of trimanganese tetroxide synthesized in example 1;

FIG. 4 is a graph showing the first 1C discharge curve (button cell CR2032, discharge cut-off voltage 3.0V) of the lithium manganate material prepared from manganomanganic oxide of example 1.

Figure 5 is a graph of button cell CR2032 discharge cycles (100 times) of the lithium manganate material made from manganomanganic oxide of example 1.

Detailed Description

Example 1

Taking 500ml of waste manganese liquid of Grignard company, firstly, adding polyethylene glycol amine into the waste manganese liquid according to the proportion of 0.2-0.4 g/l; adjusting the pH value of the solution to 3 by using 25% sodium hydroxide; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the waste manganese solution, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, separating and washing; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 60 minutes, standing for 60 minutes, and performing secondary separation and impurity removal; adding polyethylene glycol 2000 into the separated liquid at a ratio of 0.2-0.4 g/L; adjusting the pH value of the separation solution by using 25% sodium hydroxide, stirring (rotating speed 500 r/min) and heating (set temperature 65 ℃); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 9, 0.52 g of chromic oxide is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 120 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example is dark brown red in color, has 69.86% of main Mn content, has a spinel structure in crystal form and has a medium particle size of 8.22 mu m. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 125 mAh/g.

Example 2

Taking 500ml of waste manganese liquid of Grignard company, firstly, adding polyethylene glycol amine into the waste manganese liquid according to the proportion of 0.2-0.4 g/l; adjusting the pH value of the solution to 3 by using 25% sodium hydroxide; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the waste manganese solution, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, separating and washing; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, and performing secondary separation and impurity removal; adding polyethylene glycol 2000 into the separated liquid at a ratio of 0.2-0.4 g/L; adjusting pH of the separated liquid with 25% sodium hydroxide (pH = 8.7), stirring (rotation speed 500 r/min), and heating (set temperature 60 deg.C); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 8.7, 1.6 g of aluminum chloride is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 160 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example is dark brown red in color, the main content of Mn is 69.69%, the crystal form is a spinel structure, and the medium particle size is 9.23 mu m. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 120 mAh/g.

Example 3

Dissolving manganese slag of Grignard company with sulfuric acid to prepare 500ml of solution with equal content of manganese, and adding polyethylene glycol amine according to the proportion of 0.2-0.4 g/L; adjusting the pH value of the solution to 3.5 by using 25% sodium hydroxide; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the solution, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, separating and washing; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 60 minutes, standing for 60 minutes, and performing secondary separation and impurity removal; adding polyethylene glycol 4000 into the separated liquid in a ratio of 0.2-0.4 g/L; adjusting pH of the separated liquid with 25% sodium hydroxide (set pH = 10), stirring (rotation speed 500 r/min), and heating (set temperature 70 deg.C); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 10, 1.82 g of chromium chloride is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 120 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example is dark brown red in color, has 70.06% of main Mn content, has a spinel structure in crystal form and has a medium particle size of 10.5 mu m. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 125 mAh/g.

Example 4

Taking 500ml of waste manganese liquid of Grignard company, firstly, adding polyethylene glycol amine into the waste manganese liquid according to the proportion of 0.2-0.4 g/l; adjusting the pH value of the solution to 2.5 by using 25% ammonia water; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the waste manganese solution, stirring (the rotating speed is 400 r/min) for 60 minutes, standing for 60 minutes, and performing centrifugal separation and precipitation; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, and removing impurities for the second time; adding polyethylene glycol 2000 into the separated liquid at a ratio of 0.2-0.4 g/L; adjusting pH of the separated liquid with 25% ammonia water (set pH = 8.5), stirring (rotation speed 500 r/min), and heating (set temperature 60 deg.C); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 8, 0.5 g of magnesium hydroxide is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 120 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example is dark brown red in color, has 69.73% of main Mn content, has a spinel structure in crystal form and has a medium particle size of 8.56 mu m. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 120 mAh/g.

Example 5

Taking 500ml of waste manganese liquid of Grignard company, firstly, adding polyethylene glycol amine into the waste manganese liquid according to the proportion of 0.2-0.4 g/l; adjusting the pH value of the solution to 3 by using 25% ammonia water; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the waste manganese solution, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, separating and precipitating; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, and removing impurities for the second time; adding polyethylene glycol 4000 into the separated liquid in a ratio of 0.2-0.4 g/L; adjusting pH of the separated liquid with 25% ammonia water (set pH = 8.7), stirring (rotation speed 500 r/min), and heating (set temperature 65 deg.C); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 8.7, 1.02 g of aluminum oxide is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 160 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example is dark brown red in color, has 69.57% of main Mn content, has a spinel structure in crystal form and has a medium particle size of 8.75 mu m. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 120 mAh/g.

Example 6

Dissolving manganese slag of Grignard company with sulfuric acid to prepare 500ml of solution with equal content of manganese, and adding polyethylene glycol amine according to the proportion of 0.2-0.4 g/L; adjusting the pH value of the solution to 3 by using 25% ammonia water; introducing a precipitator A (manganese sulfate) according to the content of precipitable metal impurities in the solution, stirring (the rotating speed is 400 r/min) for 40 minutes, standing for 60 minutes, separating and washing; adding a precipitator B (sodium sulfide) into the separation liquid, stirring (the rotating speed is 400 r/min) for 30 minutes, standing for 60 minutes, and removing impurities for the second time; adding polyethylene glycol 4000 into the separated liquid in a ratio of 0.2-0.4 g/L; adjusting pH of the separated liquid with 25% ammonia water (set pH = 8.7), stirring (rotation speed 500 r/min), and heating (set temperature 65 deg.C); when the pH value of the solution is more than or equal to 6.5, adding 20 ml of 30% hydrogen peroxide by using a peristaltic pump (at 3 ml/min); after the pH value of the solution is adjusted to a set value of 8.7, 0.8 g of niobium oxide is added; the heating was stopped, and the mixture was stirred for another 120 minutes, separated, washed, and dried (set temperature 160 ℃ C., drying time 6 hours).

The manganomanganic oxide prepared in the example has a deep brown red color, the main content of Mn is 70.1%, the crystal form is a spinel structure, and the medium particle size is 10.62 microns. The lithium manganate is prepared from the manganous manganic oxide, and the button cell (CR 2032) detects that the 1C discharging gram capacity is more than or equal to 125 mAh/g.

The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and those skilled in the art can make various corresponding changes and modifications according to the present invention without departing from the spirit and the essence of the present invention, but these corresponding changes and modifications should fall within the protection scope of the appended claims.