Preparation method and application of silicon-based molecular sieve loaded with manganese lithium ion sieve

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a preparation method and application of a silicon-based molecular sieve loaded with a manganese lithium ion sieve. The preparation method comprises the following steps: fully stirring and complexing a lithium salt, a manganese salt and an acid aqueous solution through an acid complexing method, adding hydrophilic white carbon black and an ion introduction agent, fully stirring, drying, grinding, calcining and carrying out acid leaching treatment to obtain the silicon-based molecular sieve loaded with the manganese lithium ion sieve. According to the method, the solution loss of manganese in the acid leaching process is effectively inhibited through the acid resistance and the high specific surface area characteristic of the silicon-based molecular sieve, meanwhile, the lithium ion adsorption capacity is improved, the adsorption performance is excellent, the method is suitable for efficient extraction of lithium in the salt lake brine, and a new way is provided for green development of lithium resources.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrometallurgy, and particularly relates to a preparation method and application of a silicon-based molecular sieve loaded with a manganese-based lithium ion sieve. BACKGROUND

[0002] Lithium is widely used in lithium-ion batteries, nuclear energy, special alloys and other fields as an important resource. With the rapid development of the new energy vehicle industry, the global demand for lithium has surged, but about 72% of the proven lithium resources are contained in salt lake brine with a high magnesium-lithium ratio (Mg 2+ / Li+>500). Traditional extraction technologies (such as solvent extraction, electrodialysis, and coprecipitation) are difficult to achieve efficient lithium extraction due to poor selectivity, high energy consumption, and serious pollution. The adsorption method has become a research hotspot due to its simple operation and environmental friendliness, and the manganese-based lithium ion sieve has attracted much attention due to its high adsorption capacity and excellent selectivity. However, the manganese-based ion sieve is prone to Mn 3+ disproportionation during the acid leaching and desorption process, which seriously restricts its industrial application.

[0003] In the prior art, in order to inhibit manganese dissolution, researchers attempt to improve the material performance by doping (such as Fe, Co, Mg) or structural modification (such as poration, composite carrier loading). For example, although the manganese-based ion sieve prepared by the high-temperature solid-phase method or the hydrothermal method can improve the performance, there are still problems such as low specific surface area and uneven pore distribution, which leads to slow adsorption kinetics. In addition, the traditional carrier (such as activated carbon, metal oxide) is prone to corrosion under acidic conditions, which cannot effectively protect the active components. In recent years, silicon-based molecular sieves have been used to load adsorption materials to enhance performance due to their high specific surface area, acid resistance, and adjustable pore structure, but the existing methods (such as impregnation and physical mixing) are difficult to achieve uniform combination of active components and carriers, which leads to a significant decrease in adsorption capacity.

[0004] Therefore, it is of great significance to develop a preparation method of an adsorption material with low cost, high adsorption activity and corrosion resistance. In view of the current situation, the application aims to provide a preparation method of a silicon-based molecular sieve loaded with a manganese-based lithium ion sieve. SUMMARY

[0005] The application proposes a silicon-based molecular sieve loaded with a manganese-based lithium ion sieve prepared by an acid complexation method to optimize the pore structure and adsorption performance of the molecular sieve material, so as to solve the problems of high manganese dissolution and low material adsorption performance in the prior art.

[0006] The technical scheme adopted by the application is as follows:

[0007] A preparation method of a silicon-based molecular sieve loaded with a manganese-based lithium ion sieve, comprising the following steps:

[0008] 1) Dissolve 3-16 parts of lithium salt and 6-10 parts of manganese salt in ionized water according to mass fraction, add 21-30 parts of acid to conduct metal ion complexation reaction, then add 20-30 parts of hydrophilic white carbon black, and simultaneously add 10-20 parts of ion introduction agent, and conduct stirring reaction to form a colloid;

[0009] 2) After drying the colloid at 100-120℃ for 8 hours, conduct grinding, calcination, and annealing treatment at a temperature decreasing rate of 3℃ / min, conduct stirring acid dipping of the powder with dilute hydrochloric acid solution, retain the solid component after centrifugal separation, and conduct vacuum drying at 100-120℃ for 8 hours to obtain a silicon-based molecular sieve loaded with manganese-based lithium ion sieve (SLMO).

[0010] Further, in step 1) of the above preparation method, the lithium salt is one or a mixture of two or more of lithium chloride (LiCl), lithium sulfate (Li2SO4), and lithium nitrate trihydrate (LiNO3·3H2O).

[0011] Further, in step 1) of the above preparation method, the manganese salt is one or a mixture of two or more of manganese sulfate monohydrate (MnSO4·H2O), manganese nitrate tetrahydrate (Mn(NO3)2·4H2O), and manganese chloride tetrahydrate (MnCl2·4H2O).

[0012] Further, in step 1) of the above preparation method, the acid is one or a mixture of two or more of oxalic acid (C2H2O4), tartaric acid (C4H6O6), and citric acid (C6H8O7).

[0013] Further, in step 1) of the above preparation method, the ion introduction agent is one or a mixture of two or more of ethylene glycol, glycerol, and polysorbate-20.

[0014] Further, in step 1) of the above preparation method, the stirring reaction lasts for 45-52 hours at a temperature of 45-52℃.

[0015] Further, in step 2) of the above preparation method, the calcination is conducted by increasing the temperature to 350-450℃ at a rate of 15-20℃ / min, and the calcination lasts for 5-7 hours.

[0016] Further, in step 2) of the above preparation method, the dilute hydrochloric acid solution has a concentration of 3.0-3.7wt.%.

[0017] Further, in step 2) of the above preparation method, the acid dipping lasts for 3-5 hours at a temperature of 25-30℃.

[0018] The silicon-based molecular sieve loaded with manganese-based lithium ion sieve prepared by the above preparation method is applied in lithium extraction from salt lake brine.

[0019] The beneficial effects of this invention are as follows: This invention effectively inhibits manganese dissolution through the high specific surface area and acid resistance of silicon-based molecular sieves, and achieves uniform loading of manganese and lithium active components with the carrier by combining acid complexation method, forming a hierarchical porous structure, which significantly improves the lithium ion adsorption capacity; the preparation process is simple and environmentally friendly, requiring no complex equipment or high-energy-consuming steps, and has the advantages of low cost, high adsorption capacity and multi-scenario application potential in the efficient lithium extraction from salt lake brine, providing an innovative solution for the green development and comprehensive utilization of lithium resources. Attached Figure Description

[0020] Figure 1 Scanning electron microscope image of the silicon-based molecular sieve with manganese-based lithium ion sieve prepared in Example 1.

[0021] Figure 2 X-ray diffraction patterns of silicon-based molecular sieves with manganese-based lithium ion sieves prepared in Examples 1, 2, and 3.

[0022] Figure 3 Fourier transform infrared spectra of the silicon-based molecular sieves with manganese-based lithium ion sieves prepared in Examples 1, 2, and 3.

[0023] Figure 4 The curves showing the relationship between adsorption capacity and adsorption time for the silicon-based molecular sieves with manganese-based lithium ion sieves prepared in Examples 1, 2, and 3. Detailed Implementation

[0024] The following specific embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the present invention should be covered within the scope of the claims of the present invention.

[0025] Example 1

[0026] According to the mass fractions, 3 parts LiCl and 6 parts MnSO4·H2O were dissolved in 300 mL of deionized water, and 21 parts oxalic acid (C2H2O4) were added to carry out a metal ion complexation reaction. Then, 20 parts hydrophilic silica and 10 parts ethylene glycol were added as ion-placing agents. The reaction was carried out at 45℃ with stirring for 45 hours to form a colloid. The colloid was dried at 100℃ for 8 hours, ground, heated to 350℃ at 15℃ / min, calcined for 7 hours, and then annealed at a cooling rate of 3℃ / min. The powder was then acid-leached with 3.0 wt.% dilute hydrochloric acid solution at 25℃ with stirring for 5 hours. After centrifugation, the solid components were retained and dried under vacuum at 100℃ for 8 hours to obtain a silicon-based molecular sieve (SLMO-1) supported on a manganese-based lithium ion sieve.

[0027] The scanning electron microscope results are as follows:Figure 1 As shown in the figure, the prepared silicon-based molecular sieve crystal grains are in a microspherical structure, the small spheres are combined with each other to form a loose porous structure, and are uniformly distributed, and the particle size of the small spheres is about 10 nm, having a nano-level structure.

[0028] Example 2

[0029] According to mass fractions, 16 parts of LiNO3·3H2O and 8 parts of Mn(NO3)2·4H2O were dissolved in 300 mL of ionized water, 30 parts of citric acid (C6H8O7) was added for metal ion complexation reaction, then 25 parts of hydrophilic white carbon black was added, 15 parts of glycerol was added as an ion introduction agent, the temperature was controlled at 48°C, and the reaction was stirred for 50 hours to form a colloid, the colloid was dried at 110°C for 8 hours, then ground, the temperature was increased to 400°C at a rate of 18°C / min, calcined for 6 hours, then annealed at a cooling rate of 3°C / min, the powder was stirred with a 3.4 wt.% dilute hydrochloric acid solution at 27°C for 4 hours of acid leaching, the solid component was retained after centrifugal separation, and vacuum drying was performed at 100°C for 8 hours to obtain a manganese-based lithium ion sieve loaded silicon-based molecular sieve (SLMO-2).

[0030] Example 3

[0031] According to mass fractions, 10 parts of Li2SO4 and 10 parts of MnCl2·4H2O were dissolved in 300 mL of ionized water, 25 parts of tartaric acid (C4H6O6) was added for metal ion complexation reaction, then 30 parts of hydrophilic white carbon black was added, 20 parts of polysorbate-20 was added as an ion introduction agent, the temperature was controlled at 50°C, and the reaction was stirred for 52 hours to form a colloid, the colloid was dried at 120°C for 8 hours, then ground, the temperature was increased to 450°C at a rate of 20°C / min, calcined for 5 hours, then annealed at a cooling rate of 3°C / min, the powder was stirred with a 3.7 wt.% dilute hydrochloric acid solution at 30°C for 3 hours of acid leaching, the solid component was retained after centrifugal separation, and vacuum drying was performed at 100°C for 8 hours to obtain a manganese-based lithium ion sieve loaded silicon-based molecular sieve (SLMO-3).

[0032] The X-ray diffraction analysis spectrum of SLMO-1, SLMO-2 and SLMO-3 is shown in Figure 2 As shown in the figure, for the three different samples, on the basis of the characteristic peak of silicon dioxide, there is a characteristic peak of Li4Mn5O 12 (JCPDS 46-0810), and this Li4Mn5O 12 belongs to the Fd-3m space group, and the unit cell parameter a = 8.162, which proves that the manganese-based ion sieve loaded silicon-based molecular sieve is successfully synthesized by the acid complexation method.

[0033] Fourier transform infrared spectra of SLMO-1, SLMO-2 and SLMO-3 are shown in Figure 3 Fig. 1, from which it can be seen that there are symmetric stretching vibration peaks of Si-O bond at 800 cm -1 and 480 cm -1 , asymmetric stretching vibration peak of Si-O-Si at 1070 cm -1 , stretching vibration peak of Mn-O bond at 621 cm -1 and stretching vibration peak of Li-O bond at 532 cm -1 From the infrared analysis spectrum, it can be seen that the manganese-based ion-loaded siliceous molecular sieve is successfully synthesized by the acid method.

[0034] Application of manganese-based lithium ion-loaded siliceous molecular sieve SLMO in lithium extraction from salt lake brine

[0035] Experimental method: Take salt lake brine (Mg / Li mass ratio = 50:1, Li+concentration 0.8 g·L -1 ), add SLMO-1, SLMO-2 and SLMO-3 obtained in Examples 1-3 respectively according to solid-liquid mass ratio 1:100, and adsorb at 25℃. Then use 3.7wt.% dilute hydrochloric acid solution, and desorb at room temperature for 2 hours according to solid-liquid mass ratio 1:10.

[0036] The adsorption capacity and adsorption time relationship curve is shown in Figure 4 Fig. 2, from which it can be seen that the adsorption rate is faster at 0-15h, and gradually decreases at 15-48h and gradually tends to adsorption dynamic equilibrium. At 21h, the three manganese-based lithium ion-loaded siliceous molecular sieves all reach adsorption equilibrium, and the saturated adsorption capacities of SLMO-1, SLMO-2 and SLMO-3 are 14.72 mg·g -1 , 15.74 mg·g -1 and 15.60 mg·g -1 , respectively.

Claims

1. A method for preparing a manganese-based lithium ion sieve-loaded silicon-based molecular sieve, characterized by, The method comprises the following steps: 1) Dissolve 3-16 parts of lithium salt and 6-10 parts of manganese salt in ionized water according to mass fraction, add 21-30 parts of acid to carry out metal ion complexation reaction, then add 20-30 parts of hydrophilic white carbon black, and simultaneously add 10-20 parts of ion introduction agent, and stir to form a colloid; 2) After drying the colloid at 100-120℃ for 8 hours, grind, calcine, and then carry out annealing treatment at a temperature reduction rate of 3℃ / min, stir the powder with a dilute hydrochloric acid solution, centrifugally separate, retain the solid component, and then vacuum dry at 100-120℃ for 8 hours to obtain a manganese-loaded lithium ion sieve silicon-based molecular sieve SLMO.

2. The production method according to claim 1, characterized by, In step 1), the lithium salt is one or a mixture of two or more of lithium chloride, lithium sulfate and lithium nitrate trihydrate.

3. The preparation method according to claim 1, characterized in that, In step 1), the manganese salt is one or a mixture of two or more of manganese sulfate monohydrate, manganese nitrate tetrahydrate and manganese chloride tetrahydrate.

4. The production method according to claim 1, characterized by, In step 1), the acid is one or a mixture of two or more of oxalic acid, tartaric acid and citric acid.

5. The preparation method according to claim 1, characterized in that, In step 1), the ion introduction agent is one or a mixture of two or more of ethylene glycol, glycerol and polysorbate-20.

6. The method of claim 1, wherein, In step 1), the stirring reaction lasts for 45-52 hours at a temperature of 45-52℃.

7. The preparation method according to claim 1, characterized in that, In step 2), the calcination is carried out by increasing the temperature to 350-450℃ at a rate of 15-20℃ / min, and calcining for 5-7 hours.

8. The method of claim 1, wherein, In step 2), the dilute hydrochloric acid solution has a concentration of 3.0-3.7wt.%.

9. The method of claim 1, wherein, In step 2), the acid immersion time is 3-5 hours at a temperature of 25-30℃.

10. Use of the manganese-loaded lithium ion sieve silicon-based molecular sieve prepared by the preparation method of any one of claims 1-9 in lithium extraction from salt lake brine.

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