Method for recycling Li-ion batteries

Abstract

Lithium-containing electrochemical energy storage devices a recycled by the following steps: i) The electrochemical energy storage devices are initially comminuted and a fraction comprising an active material is separated from the comminuted material. The fraction includes carbon (C), lithium (Li) and at least one of cobalt (Co), manganese (Mn), nickel (Ni), or iron (Fe). ii) The fraction comprising active material is subsequently fed to a melt-down unit and is melted down in the presence of slag-forming agents so that a molten slag phase and a molten metal phase are formed, iii) Then, the lithium (Li) contained in the molten slag phase and/or molten metal phase is converted into a gas phase by the addition of a fluorinating agent and the carbon (C) is converted into a gas phase by the addition of an oxygen-containing gas, and the lithium and carbon are withdrawn from the process as discharge gas.

Claims

1.-12. (canceled)

13. A method for recycling lithium-containing electrochemical energy storage devices, comprising: comminuting the lithium-containing electrochemical energy storage devices to form a comminuted material and separating an active material fraction from the comminuted material, wherein the active material fraction comprises carbon (C), lithium (Li), and at least one of the elements selected from the group consisting of cobalt (Co), manganese (Mn), nickel (Ni), and iron (Fe); subsequently feeding the active material fraction to a melt-down unit and melting down the active material fraction in presence of slag-forming agents, thereby forming a molten slag phase and a molten metal phase; converting the lithium (Li) contained in the molten slag phase and/or in the molten metal phase into a gas phase by adding a fluorinating agent; converting the carbon (C) into a gas phase by adding an oxygen-containing gas; and withdrawing the lithium and the carbon as discharge gas.

14. The method according to claim 13, wherein converting the lithium (Li) contained in the molten slag phase and/or in the molten metal phase into the gas phase produces a lithium fluoride-containing gas, and wherein converting the carbon (C) into the gas phase includes oxidizing the carbon (C) with the oxygen-containing gas to carbon monoxide (CO).

15. The method according to claim 14, further comprising thermally reacting the lithium fluoride-containing gas with the carbon monoxide (CO) and oxygen to form lithium carbonate (Li.sub.2CO.sub.3).

16. The method according to claim 13, wherein a fluorine content of 0.05 to 15.0% by weight is added via the fluorinating agent in relation to the active material fraction.

17. The method according to claim 14, further comprising continuously detecting a proportion of the lithium fluoride-containing gas and/or a proportion of the carbon monoxide (CO) in the gas phase and/or in the discharge gas.

18. The method according to claim 13, wherein the method is carried out in the presence of a carrier gas.

19. The method according to claim 18, wherein the carrier gas is nitrogen.

20. The method according to claim 18, wherein the carrier gas is blown into the melt-down unit at a flow rate of at least 300 Nm.sup.3/h in relation to an amount of 1000 kg of active material.

21. The method according to claim 20, wherein the carrier gas is blown into the melt-down unit at a flow rate of at least 1000 Nm.sup.3/h in relation to an amount of 1000 kg of active material.

22. The method according to claim 20, further comprising continuously detecting the flow rate of the carrier gas.

23. The method according to claim 13, further comprising continuously detecting a temperature of the gas phase and/or of the discharge gas.

24. The method according to claim 13, further comprising separating an electrolyte-comprising fraction from the lithium-containing electrochemical energy storage devices and/or from the comminuted material, and using the electrolyte-comprising fraction as the fluorinating agent.

25. The method according to claim 24, wherein the electrolyte-comprising fraction comprises lithium hexafluorophosphate (LiPF.sub.6).

26. The method according to claim 13, wherein the active material fraction comprises aluminum (Al) in a proportion of at most 10.0% by weight.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIGS. 1 to 9 show graphs illustrating the relationship of Li recovery rate, Al proportion and temperature in simulation results.

DETAILED DESCRIPTION

[0030] The invention and the technical environment are explained in more detail below with reference to the exemplary embodiments. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly shown otherwise, it is also possible to extract partial aspects of the facts explained in the illustrated exemplary embodiments and/or figures and to combine them with other components and findings from the present description.

[0031] FIGS. 1 to 9 show the results of various examples that were carried out using a simulation tool from Factsage?. The FactPS, FToxid, FTmisc and FScopp databases were used for the calculations.

[0032] A fraction comprising active material with a composition in accordance with Table 1 below, which was analytically determined from crushed lithium-containing batteries, was used as input variables.

TABLE-US-00001 TABLE 1 C Co Cu Mn Ni O P Si Units of mass 30 6 2.6 9 11 17 0.6 0.5

[0033] In the thermodynamic calculations carried out, the following aspects of mass and energy transfer, temperature, partial pressure of oxygen of the carrier gas flow and chemistry were considered in order to investigate the distribution of the respective elements in the molten slag phase, in the molten metal phase and in the gas phase.

[0034] The following elements and compounds were identified as typical species in the gas phase: LiF; Li; (LiF).sub.2; (LiF).sub.3; Li.sub.2O; LiN; LiAlF.sub.4; Li.sub.2AlF.sub.5; LiO; AlF.sub.3;

[0035] The following elements and compounds can be identified as typical species in the molten slag phase: Al.sub.2O.sub.3; SiO.sub.2; CoO; NiO; MnO; Cu.sub.2O; Mn.sub.2O.sub.3; Li.sub.2O; LiAlO.sub.2; P.sub.2O.sub.5; LiF; LiAlF.sub.4; and small proportions of metal halides of Co; Cu; and Ni;

[0036] The molten metal phase contained the following elements: Co; Cu; Ni; Mn; C; P; Si; Li; Al; Fe;

[0037] There was also an excess of graphite.

[0038] For the results shown in FIGS. 1 to 3, thermodynamic equilibrium calculations were carried out with the parameters shown in Table 2:

TABLE-US-00002 TABLE 2 Nitrogen as the carrier gas F Al [Nm.sup.3/h related [Units [Units Temperature to 1000 kg active pO.sub.2 of mass] of mass] [? C.] material] [atm] FIG. 1 0 to 7 1400-1800 10 10.sup.?16 FIG. 1 4 FIG. 2 7 FIG. 3

[0039] The results illustrated in FIGS. 1 to 3 show, on the one hand, that the conversion of lithium in the gas phase increases with increasing temperature and, on the other hand, that an increasing fluorine content promotes the thermodynamic processes, whereas an increasing Al content in the active material impairs them.

[0040] For the results shown in FIGS. 4 to 6, thermodynamic equilibrium calculations were carried out with the parameters shown in Table 3:

TABLE-US-00003 TABLE 3 Nitrogen as the carrier gas F Al [Nm.sup.3/h related [Units [Units Temperature to 1000 kg active pO.sub.2 of mass] of mass] [? C.] material] [atm] FIG. 1 0 to 7 1400-1800 500 10.sup.?16 FIG. 4 4 FIG. 5 7 FIG. 6

[0041] In comparison to the results shown in FIGS. 1 to 3, it can be seen here that a high continuous flow of carrier gas favors the thermodynamic reaction.

[0042] For the results shown in FIGS. 7 to 9, thermodynamic equilibrium calculations were carried out with the parameters shown in Table 4:

TABLE-US-00004 TABLE 4 Nitrogen as the carrier gas F Al [Nm.sup.3/h related [Units [Units Temperature to 1000 kg active pO.sub.2 of mass] of mass] [? C.] material] [atm] FIG. 4 0 to 7 1400-1800 500 10.sup.?16 FIG. 7 4 10.sup.?14 FIG. 8 4 10.sup.?12 FIG. 9

[0043] To further investigate the influence of the partial pressure of oxygen, only the value of the partial pressure of oxygen was varied in examples 7 to 9, leaving the other parameters unchanged. In comparison to the previous examples, it can be seen here that a low partial pressure of oxygen favors the thermodynamic reaction due to the better reducing conditions.