Waste lithium battery recovery process based on carbon dioxide reinforced roasting

Abstract

The invention discloses a waste lithium battery recovery process based on carbon dioxide reinforced roasting. The waste lithium battery recovery process comprises the following steps: S1, pretreatment: disassembling, sorting, crushing and screening a discharged waste lithium battery to obtain positive and negative electrode mixed black powder; s2, CO2 reinforced roasting: mixing the anode and cathode mixed black powder with calcium oxide, introducing the mixture into a first section of a two-section roasting furnace, and roasting in a CO2 atmosphere; s3, mixed gas reduction roasting: sending a roasted product to a second section of the roasting furnace, and roasting under H2 / CO mixed gas; s4, carbonization and water leaching: performing CO2 carbonization and water leaching on the roasted product to obtain water leaching liquid and water leaching residues; s5, acid leaching: performing acid leaching on the water leaching residues obtained in the step S4 to obtain acid leaching liquid and acid leaching residues; and S6, extraction: performing impurity removal and extraction on the pickle liquor obtained in the step S5. The lithium recovery efficiency can be remarkably improved, meanwhile, the phosphorus and fluorine fixing efficiency is improved, the environmental pollution is small, and the energy consumption is low.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of resource recycling of waste lithium batteries, and particularly relates to a waste lithium battery recycling process based on carbon dioxide reinforced roasting. BACKGROUND

[0002] In recent years, the generation of a large number of waste lithium ion batteries has posed a severe challenge to electronic waste treatment and environmental protection. On the one hand, waste lithium ion batteries contain toxic and flammable electrolytes, heavy metals and other harmful components. If not properly treated, they can cause serious water and soil pollution, and even cause fires, explosions and other safety accidents. On the other hand, waste lithium ion batteries contain a large amount of lithium, cobalt, nickel, manganese, copper and other metal resources. If the battery elements can be efficiently recycled, the shortage of cobalt and lithium resources in China can be alleviated to a great extent.

[0003] There are two types of recycling processes for waste lithium batteries: pyrometallurgical recycling and hydrometallurgical recycling. The pyrometallurgical recycling process usually uses high-temperature roasting to extract valuable metals, which usually requires a high temperature of more than 1000℃, resulting in high energy consumption and the generation of toxic gases such as dioxin and fluoride. Additional tail gas treatment facilities are required, resulting in a significant increase in cost. The alloy generated by pyrometallurgical smelting needs to be further separated by hydrometallurgical process, and the overall process is complex. The purification degree and recovery rate of valuable metals in the traditional hydrometallurgical recycling process are higher than those in the pyrometallurgical recycling process, but the process is long, the efficiency is low, and a large amount of waste liquid is generated after organic solvent extraction, which also pollutes the environment. Moreover, the recovery of phosphorus and fluorine in waste lithium batteries has become a core challenge for environmental compliance. In the traditional process, most of the phosphorus and fluorine are discharged with the tail gas, causing pollution. The resource recycling of phosphorus and fluorine is challenging.

[0004] Currently, the pyrometallurgical process alone has the disadvantages of high energy consumption, high pollution and low resource utilization rate, while the conventional hydrometallurgical process is difficult to achieve selective leaching of lithium, resulting in a large amount of impurity metals in the leaching solution, high cost of subsequent impurity removal and purification, long process, and large loss of lithium. However, existing waste lithium battery recycling often only directly disposes of phosphorus and fluorine in the pyrolysis stage, resulting in waste of battery resources and failure to achieve resource recycling. SUMMARY

[0005] The purpose of the present application is to provide a waste lithium battery recycling process based on carbon dioxide reinforced roasting to solve the problems raised in the background.

[0006] In order to achieve the above purpose, the application adopts the following technical effects: A waste lithium battery recycling process based on carbon dioxide reinforced roasting, comprising the following steps: S1 pretreatment: disassembling, sorting, crushing and screening the discharged waste lithium batteries to obtain positive and negative mixed black powder; S2 CO2 reinforced roasting: the positive and negative electrode mixed black powder obtained in S1 is mixed with calcium oxide, and is roasted in the first stage of a two-stage roasting furnace under a CO2 atmosphere; S3 mixed gas reduction roasting: the roasting product of the first stage is sent to the second stage of the roasting furnace, and is roasted under a H2 / CO mixed gas; S4 carbonized water leaching: the roasting product is subjected to CO2 carbonized water leaching to obtain a water leaching solution and a water leaching residue, the water leaching solution is subjected to selective concentration separation, and lithium is recovered; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain an acid leaching solution and an acid leaching residue, the acid leaching residue is separated to obtain valuable metals of nickel, cobalt and manganese and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching solution obtained in S5 is subjected to impurity removal and extraction to obtain nickel, cobalt and manganese and recover them.

[0007] Further, in S1, the specific method is: the waste lithium battery is soaked in an inorganic salt solution for discharge treatment and drying, the completely discharged and dried battery is disassembled and sorted to obtain positive and negative electrode sheets, and finally the positive and negative electrode sheets are crushed and sieved to obtain positive and negative electrode mixed black powder.

[0008] Further, the inorganic salt solution is a sodium sulfate solution with a mass concentration of 5-10 wt %.

[0009] Further, the inorganic salt solution is a sodium sulfate solution with a mass concentration of 5 wt %.

[0010] Further, in S2, the molar ratio of the positive and negative electrode mixed black powder to calcium oxide is 1:5-5:1.

[0011] Further, in S2, the particle size of the calcium oxide is 10-100 μm.

[0012] Further, the specific method of step S2 is: the positive and negative electrode mixed black powder and calcium oxide are weighed according to the proportion, put into an air flow mill to mix and crush to obtain a mixture; the mixture is put into a ball mill tank protected by inert gas and nitrogen for ball milling; finally, the mixture after ball milling is sent to a roasting furnace with carbon dioxide for roasting to obtain a CO2 roasting product.

[0013] Further, the partial pressure of the introduced carbon dioxide is 0.03-0.3 MPa.

[0014] Further, the roasting temperature is 300-800 ℃, and the holding time is 30 min-120 min.

[0015] Further, in S3, the volume ratio of H2 to CO in the H2 / CO mixed gas is 3:1-1:3.

[0016] Further, in S3, the calcination temperature is 450℃, and the holding time is 30 min.

[0017] Further, in S3, the collected and reused CO2 after calcination is transported to the first-stage calcination.

[0018] Further, the calcination is matched with a corresponding flue gas collection device, and the collected carbon dioxide is reused after reaching the standard.

[0019] The application has the following technical effects: 1. In the pyrolysis reduction calcination, the application uses cathode graphite as a reducing agent and calcium oxide as an additive, and the calcination is carried out in a carbon dioxide atmosphere, which can accelerate the kinetics of the reduction reaction, strengthen the reduction calcination effect under low-temperature conditions, and due to the presence of carbon dioxide, active calcium carbonate is generated with calcium oxide, so that the fluorine and phosphorus fixation efficiency is significantly improved.

[0020] 2. The two-step process of carbon dioxide strengthened calcination and mixed gas reduction calcination is continuously carried out in an integrated two-stage calcination furnace, so that the electrolyte and binder in the waste lithium battery black powder are thermally decomposed, and the phosphorus and fluorine pollutants are fixed in situ, which not only avoids the liquid phase bonding of organic matter on the surface of solid materials to reduce the reaction rate of valuable metal elements, but also completes the resource utilization of pollutants.

[0021] 3. The application adopts a pyrometallurgical process The advantages of the pyrometallurgical process and the hydrometallurgical process are fully utilized, so that the method has low energy consumption and high efficiency compared with the traditional pyrometallurgical recovery process, and short cycle and cost saving compared with the traditional hydrometallurgical recovery process.

[0022] 4. The application introduces a waste gas treatment and carbon dioxide reuse system, so that the carbon dioxide pollution generated in the mixed gas reduction calcination step is completely cleaned, the whole process is low-carbon and environmentally friendly, and there is no secondary pollution. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a process flowchart of the application; Figure 2 is a phosphorus and fluorine fixation reaction path diagram of the application; DETAILED DESCRIPTION To make the purpose, technical scheme and advantages of the application clearer and more apparent, the application will be further described in detail below with reference to the drawings and preferred embodiments. However, it should be noted that many details in the description are only to make the reader have a thorough understanding of one or more aspects of the application, and the aspects of the application can be realized even without these specific details.

[0024] As shown in Figure 1 , a waste lithium battery recycling process based on carbon dioxide strengthened calcination includes the following steps: S1 Pretreatment: The waste lithium battery is soaked in a 5wt% sodium sulfate solution for discharge treatment. After soaking for 24 hours, it is sent to a drying device for thorough drying to prevent the materials from adhering to each other and affecting subsequent screening. The fully discharged and dried battery is then disassembled and sorted, and the battery cell part is sorted out. The battery cell is disassembled again to obtain positive and negative electrode sheets, a shell, and a separator. The obtained positive and negative electrode sheets are respectively subjected to multi-stage crushing using a crusher, and after crushing, screening is performed to collect the undersize powder and the oversize particles, obtaining a positive and negative mixed black powder, copper, and aluminum. The copper and aluminum can be recycled. S2 CO2 reinforced roasting: The positive and negative mixed black powder and calcium oxide are mixed and crushed in a jet mill at a molar ratio of C:Ca = 1:5~5:1 to obtain a mixture. The mixture is then placed in a ball mill tank protected by inert gas and nitrogen for ball milling. Finally, the mixture after ball milling is sent to the first stage of a one-piece two-stage roasting furnace through which carbon dioxide passes, and roasting is performed. The partial pressure of carbon dioxide is 0.03~0.3MPa, the roasting temperature is 300~800℃, and the holding time is 30min~120min, completing fluorine and phosphorus fixation and pre-reduction of metal oxides. As shown in Figure 2 In this step, under the CO2 atmosphere, the reducing agent in the roasting reaction is lithium battery negative electrode sheet graphite. Through the Boudouard reaction of graphite and carbon dioxide to generate CO, the lithium hexafluorophosphate electrolyte in the battery black powder can be decomposed into lithium fluoride and phosphorus pentafluoride through calcination, and the structure of the battery positive material, such as the layered structure of the ternary lithium battery, can be destroyed, and the high-valence oxides of Co and Mn can be reduced to low-valence oxides. During the roasting process, carbon dioxide reacts with calcium oxide to form calcium carbonate first. As the roasting temperature rises, the electrolyte begins to decompose and generate phosphorus pentafluoride. Phosphorus pentafluoride hydrolyzes to generate POF3 and HF, and reacts with calcium carbonate and unreacted calcium oxide to complete the resource recovery of phosphorus and fluorine.

[0025] The reactions involved are as follows, using Me to represent Co, Ni, and Mn: C(s)+CO2(g)=2CO(g); CO2(g)+CaO(s)=CaCO3(s); CO(g)+2LiMeO2(s)=Li2O(s)+2MeO(s)+CO2(g); C(s)+2LiMeO2(s)=Li2O(s)+2MeO(s)+CO(g); CaCO3(s)+HF(g)=CaF2(s)+H2O(g)+CO2(g); 6CaO(s) + 2POF3(g) = Ca3(PO4)2+ 3CaF2(s); PF5(g) + H2O(l) = POF3(g) + 2HF(g); CaO(s) + HF(g) = CaF2(s) + H2O(l); S3 mixed gas reduction roasting: the roasting product of the first stage is transferred to the second stage of the roasting furnace by a chain plate material conveyor, and is roasted under H2 / CO mixed gas with a volume ratio of H2 to CO of 3:1 to 1:3, the roasting temperature is 450°C, and the holding time is 30 min, so as to directionally control the reduction of valuable metals and simultaneously decompose residual graphite into CO2, and the CO2 after roasting is collected and transported back to the first stage of the roasting furnace after being pressurized by a compressor; S4 carbonization water leaching: the roasting product is subjected to CO2 carbonization water leaching to obtain water leaching liquid and water leaching residue, the water leaching liquid is subjected to selective concentration separation, and lithium is recovered; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain acid leaching liquid and acid leaching residue, the acid leaching residue is separated to obtain nickel, cobalt and manganese valuable metals and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching liquid obtained by S5 treatment is subjected to impurity removal and extraction, so as to obtain nickel, cobalt and manganese and recover them.

[0026] The following is illustrated by more specific embodiments: Example 1 A waste lithium battery recycling process based on carbon dioxide enhanced roasting, comprising the following steps: S1 pretreatment: the waste lithium battery is soaked in a 5wt% sodium sulfate solution for discharge treatment, and after soaking for 24h, it is sent to a drying equipment for sufficient drying; then the completely discharged and dried battery is disassembled and sorted, the cell part is sorted out, the cell is disassembled again, and the positive and negative electrode sheets, the shell and the separator are obtained; the obtained positive and negative electrode sheets are respectively subjected to multi-stage crushing by a crusher, and after crushing, they are sieved to collect the undersize powder and the oversize particles, respectively, to obtain positive and negative mixed black powder, copper and aluminum, and the copper and aluminum can be recovered; S2 CO2 enhanced roasting: the positive and negative mixed black powder and calcium oxide are mixed and crushed in a jet mill at a molar ratio of C:Ca = 1:3 to obtain a mixture; the mixture is then ball milled in a ball mill tank protected by inert gas and nitrogen; finally, the mixture after ball milling is sent to the first stage of an integrated two-stage roasting furnace through which carbon dioxide passes, for roasting, the partial pressure of carbon dioxide is 0.03-0.3MPa, the roasting temperature is 600°C, and the holding time is 60 min, to obtain a CO2 roasting product; S3 mixed gas reduction roasting: the roasting product of the first stage is transferred to the second stage of the roasting furnace by a chain plate material conveyor, and is roasted under H2 / CO mixed gas with a volume ratio of H2 to CO of 3:1, the roasting temperature is 450°C, and the holding time is 30 min, to directionally control the reduction of valuable metals and simultaneously decompose residual graphite into CO2, and the CO2 after roasting is collected and sent back to the first stage of the roasting furnace after being pressurized by a compressor; S4 carbonation water leaching: the roasting product is subjected to CO2 carbonation water leaching to obtain water leaching liquid and water leaching residue, the water leaching liquid is selectively concentrated and separated, and lithium is recovered; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain acid leaching liquid and acid leaching residue, the acid leaching residue is separated to obtain nickel, cobalt and manganese valuable metals and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching liquid obtained by the treatment of S5 is subjected to impurity removal and extraction to obtain nickel, cobalt and manganese and recover them.

[0027] Example 2 A waste lithium battery recycling process based on carbon dioxide enhanced roasting includes the following steps: S1 pretreatment: the waste lithium battery is soaked in a 5wt% sodium sulfate solution for discharge treatment, and after soaking for 24 h, it is sent to a drying equipment for sufficient drying; then the completely discharged and dried battery is disassembled and sorted, the battery cell part is sorted out, the battery cell is disassembled again, and positive and negative electrode sheets, a shell and a separator are obtained; the obtained positive and negative electrode sheets are respectively subjected to multi-stage crushing by a crusher, and after crushing, they are sieved to collect the undersize powder and the oversize particles, respectively, to obtain positive and negative mixed black powder, copper and aluminum, and the copper and aluminum can be recovered; S2 CO2 enhanced roasting: the positive and negative mixed black powder and calcium oxide are mixed and crushed in a jet mill at a molar ratio of C:Ca=5:1 to obtain a mixture; the mixture is then placed in a ball mill tank protected by inert gas and nitrogen for ball milling; finally, the mixture after ball milling is sent to the first stage of an integrated two-stage roasting furnace through which carbon dioxide flows, roasting is performed, the partial pressure of carbon dioxide is 0.1 MPa, the roasting temperature is 600°C, and the holding time is 60 min, to obtain a CO2 roasting product; S3 mixed gas reduction roasting: the roasting product of the first stage is transferred to the second stage of the roasting furnace by a chain plate material conveyor, and is roasted under H2 / CO mixed gas with a volume ratio of H2 to CO of 3:1, the roasting temperature is 450°C, and the holding time is 30 min, to directionally control the reduction of valuable metals and simultaneously decompose residual graphite into CO2, and the CO2 after roasting is collected and sent back to the first stage of the roasting furnace after being pressurized by a compressor; S4 carbonation water leaching: the roasting product is subjected to CO2 carbonation water leaching to obtain water leaching liquid and water leaching residue, the water leaching liquid is selectively concentrated and separated, and lithium is recovered; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain an acid leaching liquid and an acid leaching residue, the acid leaching residue is separated to obtain valuable metals of nickel, cobalt and manganese and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching liquid obtained by S5 is subjected to impurity removal and extraction to obtain nickel, cobalt and manganese and recover them.

[0028] Example 3 A waste lithium battery recycling process based on carbon dioxide reinforced roasting, comprising the following steps: S1 pretreatment: the waste lithium battery is soaked in a 5wt% sodium sulfate solution for discharge treatment, and after soaking for 24h, it is sent to a drying equipment for sufficient drying; then the completely discharged and dried battery is disassembled and sorted, the battery cell part is sorted out, the battery cell is disassembled again, and the positive and negative electrode sheets, the shell and the separator are obtained; the obtained positive and negative electrode sheets are subjected to multi-stage crushing with a crusher, and after crushing, they are sieved to collect the undersize powder and the oversize particles, respectively, to obtain positive and negative mixed black powder, copper and aluminum, and the copper and aluminum can be recovered; S2 CO2 reinforced roasting: the positive and negative mixed black powder and calcium oxide are mixed and crushed in a jet mill at a molar ratio of C:Ca=1:3 to obtain a mixture; the mixture is then placed in a ball mill tank protected by inert gas and nitrogen for ball milling; finally, the mixture after ball milling is sent to the first stage of an integrated two-stage roasting furnace through which carbon dioxide passes, for roasting, the partial pressure of carbon dioxide is 0.3MPa, the roasting temperature is 400℃, and the holding time is 30min, to obtain a CO2 roasting product; S3 mixed gas reduction roasting: the roasting product of the first stage is transferred to the second stage of the roasting furnace through a chain plate material conveyor, and is roasted under H2 / CO mixed gas with a volume ratio of H2 to CO of 1:1, the roasting temperature is 450℃, and the holding time is 30min, to directionally control the reduction of valuable metals and simultaneously decompose residual graphite into CO2, and the CO2 after roasting is collected and sent back to the first stage of the roasting furnace after being pressurized by a compressor; S4 carbonized water leaching: the roasting product is subjected to CO2 carbonized water leaching to obtain a water leaching liquid and a water leaching residue, the water leaching liquid is subjected to selective concentration and separation to recover lithium; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain an acid leaching liquid and an acid leaching residue, the acid leaching residue is separated to obtain valuable metals of nickel, cobalt and manganese and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching liquid obtained by S5 is subjected to impurity removal and extraction to obtain nickel, cobalt and manganese and recover them.

[0029] Example 4 A waste lithium battery recycling process based on carbon dioxide reinforced roasting, comprising the following steps: S1 pretreatment: the waste lithium battery is soaked in a 5wt% sodium sulfate solution for discharge treatment, after soaking for 24h, it is sent to a drying equipment for sufficient drying; then the dry battery after complete discharge is disassembled and sorted, the battery cell part is sorted out, the battery cell is disassembled again, the positive and negative electrode sheets, the shell and the separator are obtained; the obtained positive and negative electrode sheets are respectively subjected to multi-stage crushing by a crusher, and after crushing, screening is performed, and the undersize powder and the oversize particles are respectively collected, to obtain positive and negative mixed black powder, copper and aluminum, and the copper and aluminum can be recycled; S2 CO2 reinforced roasting: the positive and negative mixed black powder and calcium oxide are mixed and crushed in a jet mill at a molar ratio of C:Ca=1:5 to obtain a mixture; then the mixture is put into a ball mill tank protected by inert gas and nitrogen for ball milling; finally, the mixture after ball milling is sent to the first stage of a two-stage integrated roasting furnace through which carbon dioxide passes, for roasting, the partial pressure of carbon dioxide is 0.03 MPa, the roasting temperature is 400°C, and the holding time is 120 min, to obtain a CO2 roasting product; S3 mixed gas reduction roasting: the roasting product of the first stage is transferred to the second stage of the roasting furnace through a chain plate material conveyor, and is roasted under H2 / CO mixed gas with a volume ratio of H2 to CO of 3:1, the roasting temperature is 450°C, and the holding time is 30 min, to directionally control the reduction of valuable metals and simultaneously decompose residual graphite into CO2, at the same time, the CO2 after roasting is collected and sent back to the first stage of the roasting furnace after being pressurized by a compressor; S4 carbonized water leaching: the roasting product is subjected to CO2 carbonized water leaching to obtain a water leaching solution and a water leaching residue, the water leaching solution is selectively concentrated and separated, and lithium is recovered; S5 acid leaching: the water leaching residue obtained in S4 is subjected to acid leaching to obtain an acid leaching solution and an acid leaching residue, the acid leaching residue is separated to obtain nickel, cobalt and manganese valuable metals and calcium fluoride and calcium phosphate; S6 extraction: the acid leaching solution obtained by S5 treatment is subjected to impurity removal and extraction to obtain nickel, cobalt and manganese and recover them.

[0030] Comparative Example 1 The same as Example 1, except that step S2 is not performed in the recovery process.

[0031] Comparative Example 2 The same as Example 1, except that step S3 is not performed in the recovery process.

[0032] Recovery Experiment The filtrate obtained by vacuum filtration of the carbonized water leaching solution in Examples 1-4 and Comparative Examples 1-2 is detected for metal ions and the fluorine and phosphorus in the water leaching residue are detected, the leaching rates of the metals and the fixation efficiencies of phosphorus and fluorine are calculated, and the results are recorded in Table 1.

[0033] The calculation formula of the leaching rate of the metal is: wherein, W m represents the leaching rate of each metal, C m represents the concentration of the metal in the water leaching solution of each metal, V represents the volume of the water leaching solution, M m represents the mass of each metal in the mixed powder before roasting.

[0034] The calculation formula of the fixation efficiency of phosphorus and fluorine is: wherein, is the fixation efficiency of phosphorus and fluorine, represents the mass of phosphorus and fluorine in the water leaching residue, represents the mass of phosphorus and fluorine in the mixed powder before roasting.

[0035] Table 1 Metal leaching rate, i.e. fixation efficiency of phosphorus and fluorine As can be seen from Table 1, for the fixation efficiency, in the embodiments 1-4 of the present application, the fixation efficiency of phosphorus is 98.2%, 67.2%, 87.2% and 97.6% respectively, and the fixation efficiency of fluorine is 99.1%, 93.3%, 96.4% and 98.3% respectively, while the fixation efficiency of phosphorus and fluorine of the comparative examples 1-2 without CO2 enhanced roasting is only 13.3% and 21.6% respectively, which shows that the present application can significantly improve the fixation efficiency of phosphorus and fluorine by roasting under CO2.

[0036] For the metal leaching rate, in the embodiments 1-4 of the present application, the leaching rate of lithium is 94.7%, 93.2%, 81.3% and 94.3% respectively, which is much higher than 64.1% of the comparative example 2, and the leaching rate of the remaining metals in the embodiments 1-4 is much smaller than that of the comparative example 2, which shows that the present application can significantly improve the leaching rate of lithium and realize efficient recovery of lithium by CO2 enhanced roasting combined with mixed gas reduction roasting.

[0037] The above only describes the preferred embodiments of the application, and it should be pointed out that those skilled in the art can make some improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A waste lithium battery recycling process based on carbon dioxide enhanced roasting, characterized in that, Includes the following steps: S1 Pretreatment: Disassembling, sorting, crushing and screening the discharged waste lithium batteries to obtain a mixture of positive and negative electrode black powder. S2 CO2 enhanced roasting: The positive and negative electrode mixed black powder obtained from S1 treatment is mixed with calcium oxide and fed into the first section of a two-stage roasting furnace for roasting under a CO2 atmosphere. S3 mixed gas reduction roasting: The roasting product from the first stage is sent to the second stage of the roasting furnace and roasted under a H2 / CO mixed gas. S4 Carbonization and Water Leaching: The calcined product is subjected to CO2 carbonization and water leaching to obtain water leaching liquid and water leaching residue. The water leaching liquid is selectively concentrated and separated to recover lithium. S5 Acid Leaching: The water leaching residue obtained in S4 is acid leached to obtain acid leaching solution and acid leaching residue. The acid leaching residue is separated to obtain valuable metals such as nickel, cobalt, and manganese, as well as calcium fluoride and calcium phosphate. S6 Extraction: The acid leaching solution obtained from S5 treatment is purified and extracted to obtain and recover nickel, cobalt, and manganese.

2. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that, In S1, the specific method is as follows: the waste lithium battery is soaked in an inorganic salt solution for discharge treatment and then dried. The fully discharged and dried battery is then disassembled and sorted to obtain positive and negative electrode sheets. Finally, the positive and negative electrode sheets are crushed and sieved to obtain a mixture of positive and negative black powder.

3. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 2, characterized in that: The inorganic salt solution is a sodium sulfate solution.

4. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that: In S2, the molar ratio of the positive and negative electrode mixed black powder to calcium oxide is 1:5 to 5:

1.

5. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that: The specific method for step S2 is as follows: weigh the positive and negative electrode mixed black powder and calcium oxide according to the proportion and put them into an air jet mill to mix and pulverize them to obtain a mixture; put the mixture into a ball mill jar protected by inert gas and nitrogen to ball mill; finally, send the spherical mixture to a calcination furnace with carbon dioxide to calcinate and obtain CO2 calcination product.

6. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 5, characterized in that: The partial pressure of the introduced carbon dioxide is 0.03~0.3 MPa.

7. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 5, characterized in that: The roasting temperature is 300~800℃, and the holding time is 30min~120min.

8. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that: In S3, the volume ratio of H2 to CO in the H2 / CO mixture is 3:1 to 1:

3.

9. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that: In S3, the calcination temperature is 450℃ and the holding time is 30min.

10. The waste lithium battery recycling process based on carbon dioxide enhanced roasting according to claim 1, characterized in that: In S3, the CO2 after roasting is collected, reused, and transported to the first roasting stage.

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