Application and preparation method of a high-performance lithium silicate-based CO2 adsorbent

Abstract

This invention discloses a method for preparing a high-performance lithium silicate-based CO2 adsorbent, which involves lithium silicate (Li4SiO4) mixed with waste lithium-ion battery cathode material and crystalline silicon waste. The specific steps of the preparation method are as follows: (1) Mix and grind waste lithium-ion battery cathode material, crystalline silicon waste and Li2CO3; (2) Add an appropriate amount of deionized water to the mixture and stir evenly, then place it in a mold for pressing; (3) Place the material into a graphite crucible and place it in an induction furnace for reaction melting; (4) Take out the slag and grind it, add an appropriate amount of Li2CO3, mix thoroughly and then place it in a horizontal resistance furnace for calcination, finally obtaining the lithium silicate-based CO2 adsorbent. It reduces and recovers Ni, Co and Mn in waste lithium-ion battery cathode material, while Li+ in the battery cathode material serves as part of the lithium source and forms LixSiOy material with the by-product SiO2. The two waste materials are prepared into a high-performance CO2 adsorbent, realizing the high-value utilization of solid waste resources, reducing production costs, and having a positive impact on environmental protection.

Description

Technical Field

[0001] This invention discloses the application and preparation method of a high-performance lithium silicate-based CO2 adsorbent, which relates to the technical field. Background Technology

[0002] Li4SiO4 is used as a high-temperature CO2 adsorbent due to its excellent adsorption performance. Methods for preparing lithium silicate mainly include solid-phase methods, sol-gel methods, and co-precipitation methods. In existing research on lithium silicate preparation, most materials (Li2CO3, LiNO3, LiOH, and SiO2) are used as raw materials, resulting in high preparation costs.

[0003] To reduce costs, engineers in the field have adopted inexpensive silicon-containing materials while maintaining the adsorption performance of the adsorbent. However, in studies on the preparation of lithium silicate using existing inexpensive silicon sources, it was found that the selected silicon sources have high impurity content, which directly affects the purity of the lithium silicate material and thus leads to a decrease in CO2 adsorption performance.

[0004] Content of this invention

[0005] The purpose of this invention is to provide an application and preparation method of a high-performance lithium silicate-based CO2 adsorbent, solving the problem in the prior art that it is impossible to balance CO2 adsorption performance and manufacturing cost.

[0006] To achieve the above-mentioned technical objectives and effects, the invention is implemented through the following technical solution:

[0007] A high-performance lithium silicate-based CO2 adsorbent comprises lithium silicate (Li4SiO4) doped with used lithium-ion battery cathode material and crystalline silicon waste.

[0008] Furthermore, it can be applied to adsorb CO2.

[0009] Another objective of this invention is to disclose the application of a high-performance lithium silicate-based CO2 adsorbent, which has a saturated adsorption capacity of 22.43wt%-34.20wt% for isothermal adsorption of CO2 at 700℃.

[0010] Another objective of this invention is to disclose a method for preparing a high-performance lithium silicate-based CO2 adsorbent, the specific steps of which are as follows:

[0011] (1) Mix and grind waste lithium-ion battery cathode material, crystalline silicon waste and Li2CO3;

[0012] (2) Add an appropriate amount of deionized water to the mixture and stir evenly. Then, put it into a mold for tableting.

[0013] (3) The material is loaded into a graphite crucible and placed in an induction furnace for reaction melting;

[0014] (4) Take out the smelting slag and grind it. Add an appropriate amount of Li2CO3, mix thoroughly, and then put it into a horizontal resistance furnace for calcination to finally obtain lithium silicate-based CO2 adsorbent.

[0015] Furthermore, in step (1), waste lithium-ion battery cathode material and Li2CO3 are used as lithium sources for preparing Li4SiO4 material, and crystalline silicon waste is used as silicon source for preparing Li4SiO4 material. The materials are prepared by controlling the Li / Si ratio in the system to be 4 to 4.4 mol.

[0016] Furthermore, in step (2), deionized water is added to the mixture to increase the viscosity between the materials, and the ratio of the mixture to water is controlled to be 10g / ml.

[0017] Furthermore, in step (2), the mixture is loaded into a mold with a diameter of 25 mm, and the pressure is controlled within the range of 10 MPa-15 MPa.

[0018] Furthermore, in step (3), the induction furnace is used for reaction melting, and the temperature is controlled within the range of 1500℃~1550℃ for 1 hour.

[0019] Furthermore, in step (4), the composition ratio of Li4SiO4 to Li2SiO3 is calculated by RIR semi-quantitative analysis based on the XRD phase of the smelting slag, and Li2CO3 is added and calcined to obtain CO2 adsorbent.

[0020] Furthermore, in step (4), argon gas is introduced into a horizontal resistance furnace and calcined for 2 to 6 hours at a temperature range of 600°C to 900°C to obtain Li4SiO4 material.

[0021] Beneficial effects:

[0022] This invention uses silicon waste generated in the photovoltaic industry as a reducing agent to reduce and recover Ni, Co, and Mn from waste lithium-ion battery cathode materials. Simultaneously, Li+ from the battery cathode material serves as a partial lithium source, reacting with the byproduct SiO2 to form LixSiOy material. These two types of waste are then used to prepare a high-performance CO2 adsorbent, achieving high-value utilization of solid waste resources, reducing production costs, and having a positive impact on environmental protection.

[0023] Due to the problem that a large amount of smelting slag cannot be effectively treated in the pyrometallurgical recycling process of waste lithium batteries, this invention makes reasonable use of smelting slag by adding Li2CO3 as a slag-forming agent and controlling the composition of smelting slag to be LixSiOy. Using smelting slag as a raw material for preparing Li4SiO4 can optimize the reaction process of the roasting experiment and reduce the reaction temperature and time.

[0024] High-purity silicon from crystalline silicon waste is used to reduce and remove most of the Ni, Co, and Mn in the cathode material of waste lithium-ion batteries. The unreduced Mn3+ remains in the lithium silicate slag and plays a role in doping and modification. Compared with the Li4SiO4 material prepared by the traditional solid-state method, it has the characteristics of large specific surface area, small particle size, and loose and porous structure, which is conducive to increasing the contact area between CO2 and Li4SiO4 material and has good CO2 adsorption performance.

[0025] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of the method for preparing high-performance lithium silicate-based CO2 adsorbent according to an embodiment of the present invention.

[0027] Figure 2 The results are the carbon dioxide adsorption test results described in the embodiments of the present invention. Detailed Implementation

[0028] To more clearly illustrate the technical solution of the present invention, the present invention will be described in detail below with reference to embodiments.

[0029] Example 1

[0030] A method for preparing high-performance lithium silicate-based CO2 adsorbents (see...) Figure 1 The specific steps are as follows:

[0031] (1) Take 20g of waste battery positive electrode material, 5g of crystalline silicon waste and 17.5g of Li2CO3, mix them and put them into a beaker. Add 4ml of deionized water and stir well.

[0032] (2) Place the mixture obtained in step (1) into a mold and maintain the pressure at 15 MPa for 10 minutes;

[0033] (3) Place the block material from step (2) into a graphite crucible, wrap the crucible with a layer of heat-insulating cotton, and keep the melting temperature at 1550℃ in an induction furnace for 1 hour. After the temperature inside the furnace drops to room temperature, take it out and process it to obtain lithium silicate slag.

[0034] (4) Grind the lithium silicate slag obtained in step (3) into powder, add some Li2CO3, mix well and put it into a horizontal resistance furnace, introduce argon gas, control the heating rate to be 10℃ / min, raise it to 600℃ and keep it for 4 hours to obtain Li4SiO4 material.

[0035] The results are as follows Figure 2 The figure shows the weight change curve of the Li4SiO4 material obtained in Example 1 when it is isothermally adsorbed CO2 at 700℃, with a saturated adsorption capacity of 22.43 wt%.

[0036] Example 2

[0037] A method for preparing high-performance lithium silicate-based CO2 adsorbents (see...) Figure 1 The specific steps are as follows:

[0038] (1) Take 20g of waste battery positive electrode material, 5g of crystalline silicon waste and 17.5g of Li2CO3, mix them and put them into a beaker. Add 4ml of deionized water and stir well.

[0039] (2) Place the mixture obtained in step (1) into a mold and maintain the pressure at 15 MPa for 10 minutes;

[0040] (3) Place the block material from step (2) into a graphite crucible, wrap the crucible with a layer of heat-insulating cotton, and keep the melting temperature at 1550℃ in an induction furnace for 1 hour. After the temperature inside the furnace drops to room temperature, take it out and process it to obtain lithium silicate slag.

[0041] (4) Grind the lithium silicate slag obtained in step (3) into powder, add some Li2CO3, mix well and put it into a horizontal resistance furnace, introduce argon gas, control the heating rate to be 10℃ / min, raise it to 700℃ and keep it for 4 hours to obtain Li4SiO4 material.

[0042] The results are as follows Figure 2 The figure shows the weight change curve of the Li4SiO4 material obtained in Example 1 when it is isothermally adsorbed CO2 at 700℃, with a saturated adsorption capacity of 31.17wt%.

[0043] Example 3

[0044] A method for preparing high-performance lithium silicate-based CO2 adsorbents (see...) Figure 1 The specific steps are as follows:

[0045] (1) Take 20g of waste battery positive electrode material, 5g of crystalline silicon waste and 17.5g of Li2CO3, mix them and put them into a beaker. Add 4ml of deionized water and stir well.

[0046] (2) Place the mixture obtained in step (1) into a mold and maintain the pressure at 15 MPa for 10 minutes;

[0047] (3) Place the block material from step (2) into a graphite crucible, wrap the crucible with a layer of heat-insulating cotton, and keep the melting temperature at 1550℃ in an induction furnace for 1 hour. After the temperature inside the furnace drops to room temperature, take it out and process it to obtain lithium silicate slag.

[0048] (4) Grind the lithium silicate slag obtained in step (3) into powder, add some Li2CO3, mix well and put it into a horizontal resistance furnace, introduce argon gas, control the heating rate to be 10℃ / min, raise it to 800℃ and keep it for 4 hours to obtain Li4SiO4 material.

[0049] The results are as follows Figure 2 The figure shows the weight change curve of the Li4SiO4 material obtained in Example 1 when it is isothermally adsorbed CO2 at 700℃, with a saturated adsorption capacity of 34.20 wt%.

[0050] Example 4

[0051] A method for preparing high-performance lithium silicate-based CO2 adsorbents (see...) Figure 1 The specific steps are as follows:

[0052] (1) Take 20g of waste battery positive electrode material, 5g of crystalline silicon waste and 17.5g of Li2CO3, mix them and put them into a beaker. Add 4ml of deionized water and stir well.

[0053] (2) Place the mixture obtained in step (1) into a mold and maintain the pressure at 15 MPa for 10 minutes;

[0054] (3) Place the block material from step (2) into a graphite crucible, wrap the crucible with a layer of heat-insulating cotton, and keep the melting temperature at 1550℃ in an induction furnace for 1 hour. After the temperature inside the furnace drops to room temperature, take it out and process it to obtain lithium silicate slag.

[0055] (4) Grind the lithium silicate slag obtained in step (3) into powder, add some Li2CO3, mix well and put it into a horizontal resistance furnace, introduce argon gas, control the heating rate to be 10℃ / min, raise it to 900℃ and keep it for 4 hours to obtain Li4SiO4 material.

[0056] The results are as follows Figure 2 The figure shows the weight change curve of the Li4SiO4 material obtained in Example 1 when it is isothermally adsorbed CO2 at 700℃, with a saturated adsorption capacity of 32.38 wt%.

[0057] The above are merely some of the embodiments of this application and are not intended to limit the application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments shall still fall within the scope of protection of the technical solution of this application.

Claims

1. A method for preparing a high-performance lithium silicate-based CO2 adsorbent, characterized in that, The high-performance lithium silicate-based CO2 adsorbent comprises: lithium silicate Li4SiO4 doped with used lithium-ion battery cathode material and crystalline silicon waste; the high-performance lithium silicate-based CO2 adsorbent is applied to adsorb CO2, and the saturated adsorption capacity of CO2 at a constant temperature of 700℃ is 22.43wt%-34.20wt%; the specific steps of the preparation method are as follows: (1) Mix and grind waste lithium-ion battery cathode material, crystalline silicon waste and Li2CO3; (2) Add an appropriate amount of deionized water to the mixture and stir evenly. Then, put it into a mold for tableting. (3) The material is loaded into a graphite crucible and placed in an induction furnace for reaction melting; (4) Take out the smelting slag and grind it. Add an appropriate amount of Li2CO3, mix thoroughly, and then put it into a horizontal resistance furnace for calcination to finally obtain lithium silicate-based CO2 adsorbent. In step (1), waste lithium-ion battery cathode material and Li2CO3 are used as lithium sources for preparing Li4SiO4 material, and crystalline silicon waste is used as silicon source for preparing Li4SiO4 material. The materials are prepared by controlling the Li / Si ratio in the system to be 4 to 4.4 mol. In step (2), deionized water is added to the mixture to increase the viscosity between the materials, and the ratio of the mixture to water is controlled to be 10g / mL. In step (2), the mixture is loaded into a mold with a diameter of 25 mm, and the pressure is controlled within the range of 10 MPa-15 MPa. In step (3), the reaction melting in the induction furnace is controlled at a temperature of 1500℃~1550℃ for 1 hour. In step (4), the composition ratio of Li4SiO4 to Li2SiO3 is calculated by RIR semi-quantitative analysis based on the XRD phase of the smelting slag, and Li2CO3 is added and calcined to obtain CO2 adsorbent. In step (4), argon gas is introduced into a horizontal resistance furnace and calcined for 2 to 6 hours at a temperature range of 600°C to 900°C to obtain Li4SiO4 material.

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