METHOD FOR RECYCLING LI-ION BATTERIES

Abstract

A method for recycling a battery including the following steps: a) dissolution of a battery waste, for example an electrode, including lithium and a metal selected from cobalt and manganese, such that a solution to be treated containing lithium ions and metal ions is formed, b) addition of a peroxymonosulfate salt to the solution to be treated, the solution to be treated being regulated at a pH ranging from 1 to 4 when the metal is cobalt or at a pH ranging from 0.1 to 2.5 when the metal is manganese, such that the metal ions are selectively precipitated in the form of metal oxyhydroxide, c) separation of the lithium ions from the solution to be treated. Advantageously, the solution further comprises nickel ions.

Claims

1.-10. (canceled)

11. A method for recycling a battery including the following steps: a) dissolution of a battery waste, including lithium and a metal selected from cobalt and manganese, such that a solution to be treated containing lithium ions and metal ions is formed, b) addition of a peroxymonosulfate salt to the solution to be treated, the solution to be treated being regulated at a pH ranging from 1 to 4 when the metal is cobalt or at a pH ranging from 0.1 to 2.5 when the metal is manganese, such that the metal ions are selectively precipitated in the form of metal oxyhydroxide, c) separation of the lithium ions from the solution to be treated.

12. The method according to claim 11, wherein the battery waste includes both cobalt and manganese.

13. The method according to claim 12, wherein step b) is repeated twice: one time to selectively make the manganese ions precipitate and the other time to selectively make the cobalt ions precipitate.

14. The method according to claim 13, wherein it includes the following successive steps: step a), a step during which the pH of the solution to be treated in increased and set between 7 and 10, by addition of a base such as NaOH, NH.sub.4OH or Na.sub.2CO.sub.3, such that a precipitate comprising cobalt and manganese is formed, step c), dissolution of the precipitate comprising cobalt and manganese, implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 0.1 to 2.5 to selectively make the manganese ions precipitate in the form of manganese oxyhydroxide, implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 1 to 4 to selectively make the cobalt ions precipitate in the form of cobalt oxyhydroxide.

15. The method according to claim 11, wherein the battery waste further includes nickel, the dissolution of the battery waste leading to the formation of nickel ions.

16. The method according to claim 15, wherein the method includes a step during which the pH is increased between 7 and 10, by addition of a base such as NaOH, NH.sub.4OH or Na.sub.2CO.sub.3, such that the nickel ions are precipitated.

17. The method according to claim 16, wherein the base is NaOH, NH.sub.4OH or Na.sub.2CO.sub.3.

18. The method according to claim 11, wherein the temperature ranges from 20° C. to 95° C.

19. The method according to claim 18, wherein the temperature ranges from 40° C. to 80° C.

20. The method according to claim 11, wherein the peroxymonosulfate salt is potassium peroxymonosulfate.

21. The method according to claim 11, wherein the peroxymonosulfate salt is potassium peroxymonosulfate triple salt.

22. The method according to claim 11, wherein step c) is carried out by adding carbonate or with a resin.

23. The method according to claim 11, wherein the battery waste is a nickel-manganese-cobalt electrode.

24. The method according to claim 11, wherein the battery waste is an electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present invention will be better understood upon reading the description of embodiments provided for indicative and non-limiting purposes with reference to the appended FIG. 1.

[0059] FIG. 1 is a graph representing the evolution of the manganese separation efficiency according to the nature of the ions in the solution, at room temperature for an Oxone® equivalence with respect to manganese, according to a particular embodiment of the invention.

DETAILED DISCLOSURE OF PARTICULAR EMBODIMENTS

[0060] Although this is not limiting in any way, the invention finds particular applications in the field of recycling and/or valorisation of Li-ion type batteries/accumulators/cells, and in particular of their electrodes.

[0061] Next, reference will be made to a battery, but it could consist of a cell or of an accumulator.

[0062] Next, by battery waste, it should be understood the battery or a portion of the battery that has been recovered after safeguarding and dismantling the battery.

[0063] For example, the battery waste comprises lithium as well as cobalt and/or manganese and, possibly nickel. According to a particular embodiment, the battery waste is an electrode whose active material may be LiCoO.sub.2, LiMnO.sub.2 or LiNi.sub.0.33Mn.sub.0.33Co.sub.0.33. (NMC). The NMC electrode may have different nickel, cobalt and manganese rations. For example, the ratio may be 1/1/1 or 6/2/2 or 8/1/1.

[0064] The battery waste may further contain other species. The other species may be metals, alkaline metals and/or rare earths. As an illustrative and non-limiting example, mention may be made of the following elements: Fe, Zn, Al, Mg, Cu, Ca, Pb, Cd, La, Nd and Ce.

[0065] Advantageously, the battery waste is crushed such that crushings are formed. Alternatively, the method may also be carried out directly on a non-crushed battery waste.

[0066] The method for valorising the battery waste comprises at least the following steps:

[0067] a) dissolution of the battery waste including lithium and a divalent metal selected from cobalt and manganese, and possibly nickel, such that a solution to be treated is formed containing lithium ions, ions of the divalent metal, and possibly nickel ions,

[0068] b) addition of a peroxymonosulfate salt to the solution to be treated, the solution to be treated being set at a pH ranging from 0.1 to 2.5 when the divalent metal is manganese or at a pH ranging from 1 to 4 when the divalent metal is cobalt, such that the ions of the divalent metal are selectively precipitated in the form of metal oxyhydroxide,

[0069] c) separation of the lithium ions,

[0070] d) possibly separation of the nickel ions.

[0071] For example, the steps may be carried out according to the order a), b), c), d) or according to the order a), c), b), d).

[0072] According to a first advantageous variant, the method comprises, more particularly, the following successive steps:

[0073] dissolution of the battery waste, in an acid medium,

[0074] possibly, elimination of the impurities,

[0075] separation of manganese, according to the implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 0.1 to 2.5 and/or separation of cobalt according to the implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 1 to 4,

[0076] possibly, separation of nickel, by precipitation in a basic medium,

[0077] separation of lithium,

[0078] regeneration of the medium.

[0079] According to a second advantageous variant, the method comprises, more particularly, the following successive steps:

[0080] dissolution of the battery waste, in an acid medium,

[0081] possibly, elimination of the impurities,

[0082] formation of a manganese and/or cobalt and, possibly, nickel precipitate, by precipitation,

[0083] separation of lithium,

[0084] dissolution of the precipitate,

[0085] separation of manganese, according to the implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 0.1 to 2.5 and/or separation of cobalt according to the implementation of step b) by addition of a peroxymonosulfate salt at a pH ranging from 1 to 4,

[0086] possibly, separation of nickel, by precipitation in a basic medium,

[0087] regeneration of the medium.

[0088] The peroxymonosulfate salt, also called monopersulfate or peroxysulfate, is an inexpensive compound with a low environmental impact. The compound is stable, and could be handled without any risk or significant precautions, in contrast with the other processes of the prior art (Cl.sub.2, O.sub.3, SO.sub.2/O.sub.2, . . .). The by-products of the reaction are essentially sulphates which is an advantage, with regards to processes based on chlorides (generation of Cl.sub.2). The oxidising precipitation is selective and efficient.

[0089] Preferably, the peroxymonosulfate salt is a potassium peroxymonosulfate salt. It may consist of a triple salt. The formula of the potassium peroxymonosulfate triple salt is 2KHSO.sub.5.KHSO.sub.4.K.sub.2SO.sub.4. For example, such a product is commercialised under the reference Oxone®. It is also possible to use the potassium peroxymonosulfate triple salt commercialised under the reference Caroat®.

[0090] It may also consist of a sodium peroxymonosulfate salt. According to a first variant, the peroxymonosulfate salt may be introduced in a liquid form. For example, it is solubilised beforehand in water. It has the advantage of being very soluble in water (250 g/L), which reduces the amount of effluents derived from the process.

[0091] According to a second variant, the peroxymonosulfate salt is introduced in a solid form in the solution to be treated. This avoids adding an aqueous solvent in the solution to be treated.

[0092] Advantageously, the peroxymonosulfate salt is introduced with a flow rate ranging from 0.1 g per minute per litre of solution (g/min/L.sub.solution) to 30 g/min/L.sub.solution and preferably from 1 to 10 g/min/L.sub.solution.

[0093] Preferably, the manganese extraction (manganese removal) step is carried out with a solution containing both cobalt ions and nickel ions. Indeed, the efficiency of manganese removal is particularly high when the solution contains both peroxymonosulfate salt and cobalt, and possibly nickel (FIG. 1).

[0094] Advantageously, the ratio between the cobalt concentration and the manganese concentration ranges from 0.1 to 10, and preferably from 0.5 to 1. Such a range leads to an efficient extraction of manganese while limiting the risks of entrainment during precipitation.

[0095] Preferably, to extract cobalt, a pH from 2 to 3 is selected. For example, a pH in the range of 3 will be selected.

[0096] Preferably, the cobalt concentration in the solution is higher than 0.5 g/L and still more preferably higher than 1 g/L. Preferably, the cobalt concentration is lower than 50 g/L and still more preferably lower than 40 g/L to avoid the effects of entrainment which would reduce the purity of the end product.

[0097] Preferably, to extract manganese, a pH from 0.75 to 1.5 is selected. For example, a pH of 0.9 will be selected.

[0098] Preferably, the manganese concentration, in the solution to be treated, is higher than 0.1 g/L, more preferably higher than 0.5 g/L and still more preferably higher than 1 g/L. Preferably, the manganese concentration is lower than 50 g/L and still more preferably lower than 40 g/L to avoid the effects of entrainment which would reduce the purity of the end product.

[0099] To ensure a stable pH, a servo-control is carried out during the introduction of the peroxymonosulfate salt. The servo-control may be carried out with a base such as NaOH, Na.sub.2CO.sub.3 or NH.sub.4OH. The base may be introduced in a liquid or solid form. Advantageously, sodium carbonate in a solid form is selected to reduce the effluents.

[0100] To retrieve nickel, the pH is increased between 7 and 10, by addition of a base such as NaOH, NH.sub.4OH or Na.sub.2CO.sub.3, such that nickel is precipitated.

[0101] Preferably, the solution is an aqueous solution. It may also consist of an organic solution.

[0102] The treatment temperature may range from 20° C. to 95° C., preferably from 30° C. to 90° C., and still more preferably from 40° C. to 80° C. For example, a temperature in the vicinity of 50° C. is selected.

[0103] Preferably, the pressure is room pressure (in the range of 1 bar).

[0104] The method may include another step during which another element present in the solution to be treated and having a high added value is advantageously recovered.

[0105] Illustrative and non-limiting example of one embodiment:

[0106] The battery waste (“blackmass”) is primarily composed of cobalt. The composition (in mass percentage) of this waste is provided in the following table:

TABLE-US-00001 Composition (%.sub.m) Li Ni Mn Co Fe Al Cu Na K Ca Cd P 3.58 4.29 2.09 19.32 4.33 2.66 2.96 0.15 0.12 0.24 0.08 2.87

[0107] The remainder corresponds to carbon and oxygen.

[0108] During a first step, the waste is dissolved in a sulfuric acid solution with a solid-on-liquid ratio of 15%. The dissolution is carried out at room temperature in 5L of water. The pH is set at 2 thanks to a system for servo-controlling pH which continuously injects sulfuric acid. Afterwards, the medium is left under stirring for one hour. Stirring is ensured at a speed of 400 rpm by a “4 winged” type blade, equipped with a scraper to prevent particle agglomeration.

[0109] After dissolution, the pH is raised to 5 with solid sodium carbonate, then 0.35% by volume of hydrogen peroxide (30%) is added, which corresponds to stoichiometric equivalence with respect to iron remaining in the solution. After a stabilisation period of about 30 minutes, the mixture is filtered. A filtrate rich in Li, Ni, Mn and Co and a solid, rich in C, Cu, Fe and Al, are recovered.

[0110] The filtrate is then treated in order to selectively eliminate manganese. The considered reaction is an oxidising precipitation, which takes place by continuous addition of solid Oxone®. The oxidant flow rate is 1.5 g/min/L. The pH is continuously set at 0.9 by addition of solid sodium carbonate. Stirring is ensured at a speed of 400 rpm by a “4 winged” type blade. The system is at a temperature of 50° C. The end of the reaction is defined by the duration of addition of Oxone®. The amount of reagent to be added is calculated in order to obtain a stoichiometric equivalence with respect to manganese present in the solution.

[0111] Throughout the experiment, breaks are scheduled ever 0.2 Oxone® equivalences: for 15 minutes, the reactant is no longer added in the medium in order to stabilise the system and reach chemical balance. Once the Oxone® total addition is completed, the mixture is filtered. Manganese is completely retrieved from the solution and a filtrate rich in Ni and Co and a manganese dioxide solid with a purity of more than 98% (dosage by an Inductively Coupled Plasma or ICP technique) are obtained.

[0112] The filtrate rich in Ni and Co is treated in order to selectively recover cobalt. The considered reaction is an oxidising precipitation, by addition of solid Oxone®, continuously dispensed at 50° C., at a pH set at 3 by addition of solid sodium carbonate. The oxidant flow rate is 1.5 g/min/L. Stirring is ensured at a speed of 400 rpm by a “4 winged” type blade. The end of the reaction is defined by the duration of addition of Oxone®. The amount of reagent to be added is calculated in order to obtain a stoichiometric equivalence with respect to cobalt present in the solution. The ICP dosage of the solid indicates a purity of >99% of the product.

[0113] Afterwards, the filtrate is treated in order to extract nickel. The considered reaction is a precipitation in a basic medium in the form of a carbonate. The pH is increased up to 9 by addition of solid sodium carbonate. The reaction takes place at room temperature. Stirring is ensured at a speed of 400 rpm by a “4 winged” type blade.