BATTERY RECYCLING BY TREATMENT OF THE LEACH WITH METALLIC NICKEL

Abstract

Process for the recovery of transition metal from cathode active materials containing nickel and lithium, wherein said process comprises the steps of (a) treating a lithium containing transition metal oxide material with a leaching agent (preferably an acid selected from sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, oxalic acid and citric acid), (b) adjusting the pH value to 2.5 to 8, and (c) treating the solution obtained in step (b)with metallic nickel, cobalt or manganese or a combination of at least two of the foregoing.

Claims

1.-15. (canceled)

16. A process for the recovery of transition metal from cathode active materials containing nickel and lithium, wherein said process comprises the steps of (a) treating a lithium containing transition metal oxide material with a leaching agent, (b) adjusting the pH value to 2.5 to 8, and (c) treating the solution obtained in step (b) with metallic nickel, cobalt or manganese or a combination of at least two of the foregoing.

17. The process according to claim 16, wherein between steps (b) and (c) a step (bl) is performed, said step (b1) comprising the removal of precipitates of phosphates, tungstate, oxides, hydroxides or oxyhydroxides of Al, Fe, Zr, Zn, Ca or Cu or combinations of at least two of the foregoing.

18. The process according to claim 16, wherein the cathode active materials from which transition metals are to be recovered also contain at least one of cobalt and manganese.

19. The process according to claim 16, wherein step (b) is performed by the addition of at least one of sodium hydroxide, lithium hydroxide, ammonia and potassium hydroxide.

20. The process according to claim 16, wherein step (c) is performed at a temperature in the range of from 25 to 60° C.

21. The process according to claim 16, wherein step (c) is performed at a pH value in the range from 2 to 5.

22. The process according to claim 16, wherein prior to step (a) a removal of carbon and polymeric material is performed by at least one of the following methods: gravity concentration or flotation or dense media separation or magnetic separation.

23. The process according to claim 16, wherein in step (a) a reducing agent is added.

24. The process according to claim 16, wherein between step (a) and step (b) a step (a1) is performed said step (a1) including the removal of non-dissolved solids.

25. The process according to claim 16, wherein said process comprises the additional step (d) of precipitation of nickel and, optionally, cobalt or manganese as mixed hydroxide, mixed oxyhydroxide or mixed carbonate.

26. The process according to claim 16, including an additional step (e1) of recovering the lithium by way of precipitation as carbonate or hydroxide.

27. The process according to claim 16, wherein including the additional step (e2) of recovering the lithium by way of electrolysis or electrodialysis.

28. The process according to claim 16, wherein the leaching agent comprises an acid selected from sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, oxalic acid and citric acid.

29. The process according to claim 16, wherein the solution obtained from step (c) is treated by hydrogen injection in the solution at a temperature above 100° C. and a partial pressure above 5 bar to precipitate metal and optionally followed by separation of the obtained precipitate.

30. The process according to claim 16, wherein the solution obtained from step (c) is treated by hydrogen injection in the solution at a temperature above 100° C. and a partial pressure above 5 bar to precipitate metal which is nickel and/or cobalt, and optionally followed by separation of the obtained precipitate.

31. The process according to claim 16, wherein the solution obtained from step (c) is treated by electrolysis of an electrolyte containing said solution.

Description

EXAMPLES

[0122] General remark: percentages are % by weight unless expressly indicated otherwise. The metal impurities and phosphorous were determined by elemental analysis using ICP-OES (inductively coupled plasma—optical emission spectroscopy) or ICP-MS (inductively coupled plasma—mass spectrometry). Total carbon was determined with a thermal conductivity detector (CMD) after combustion. Fluorine was detected with an ion sensitive electrode (ISE) after combustion for total fluorine or after H.sub.3PO.sub.4 distillation for ionic fluoride.

[0123] An amount of 900 g mechanically treated battery scrap (particle size D50 about 20 μm) containing [0124] 360 g spent cathode active material containing nickel, cobalt and manganese in similar molar amounts; and a 1/1 molar ratio of Li to the sum of Ni, Co, and Mn as determined by elemental analysis, [0125] 430 g of organic carbon in the form of graphite and soot and residual electrolyte, and [0126] 75 g of further impurities comprising Al (16 g), Cu (14.4), F (in total: 31.5 g), Fe (2.7 g), P (7.65 g), Zn (0.72 g), Mg (40 ppm), Ca (40 ppm), ppm referring to total of the above battery scrap,

[0127] was slurried in 2.5 kg water and stirred vigorously for 1 hour. Then, the solids were separated by filtration, washed with 1.5 kg water, and then re-slurried in 480 g deionized water in a 2.5 L stirred batch reactor.

[0128] All impurity contents are given as weight percentages unless specifically noted otherwise, and refer to the total amount of mechanically treated battery scrap. By the above treatment, about 50% of the organic fluoride was removed.

[0129] Step (a.1): treatment with acid

[0130] A mixture of 1570 g H.sub.250.sub.4 (50% H.sub.250.sub.4 in water) and 267 g hydrogen peroxide (30% H.sub.2O.sub.2 in water) was added dropwise to the above slurry under vigorous stirring. The temperature of the slurry was kept between 30 and 40° C. After completion of the addition, the resulting reaction mixture was stirred for another 30 min at 30° C., heated to 60° C. for 2 hours and then cooled to ambient temperature. Solids were removed from the resultant slurry by suction filtration. The filter cake was washed with 150 g deionized water. The combined filtrates (2728 g) contained 78 g Ni, 75 g Co, 61 g Mn, and 27 g Li, corresponding to leaching efficiencies >98% for all 4 metals.

[0131] Steps (b.1) and (b2.1): pH adjustment

[0132] The pH value of 2020 g of the combined filtrates from step (a.1) was adjusted to pH 6.5 by adding 988 g of a 4 molar caustic soda solution under stirring. Precipitate formation could be observed. After stirring for another 30 min the solids were removed by suction filtration. The obtained filtrate (2773 g) contains impurity levels of Al, P, Zn, Mg, Ca, and Fe below 5 ppm, and about 40 ppm of Cu.

[0133] Step (c.1): Treatment with metallic nickel The filtrate from step (b2.1) was poured into a 2.5 L stirred batch reactor, 22.3 g nickel powder (max. diameter 150 μm, commercially available from Sigma Aldrich Chemie GmbH) were added, an amount of 18.4 g 50 wt % H.sub.2SO.sub.4 was added. The resultant mixture had a pH value of 2.75. It was then heated to 60° C. for 7 hours and allowed to cool to ambient temperature. After cooling, the solids were removed by filtration, (c.1), and the filtrate was again subjected to 20.3 g nickel powder, heated at 60° C. for 7 hours, and filtered to provide 2614 g of a Ni, Co, Mn and Li containing solution with a copper content below 1 ppm.

[0134] Recovery yields: Ni: 90%, Co: 92%, Mn: 94%, Li: 92%

[0135] Step (d.1): precipitation

[0136] A 2.5-I-stirred batch reactor was charged with 2606 g of the solution obtained under (c.1). Under an atmosphere of argon, the pH value was adjusted to 12.0 under vigorous stirring by dropwise addition of 1,341 g of an aqueous NaOH:NH.sub.3 mixture made from 1.25 kg of a 4 molar aqueous NaOH solution and 113 g of an aqueous 25 wt % ammonia solution. After stirring at ambient temperature for 16 hours, the resultant slurry was filtered with a pressure filter applying an inert gas pressure of 4.5 atm. 3002 g of a clear and colorless solution containing 0.43 g/I Li and 4.8 g/I Na was obtained. After completion of the filtration, the filter cake was re-slurried in 2.3 kg deionized and degassed water, stirred for one hour and filtered with a pressure filter to give 2327 g of a clear and colorless solution containing 0.12 g/I Li and 1.3 g/I Na. After completion of the filtration, the filter cake was re-slurried in 2660 g deionized and degassed water, stirred for one hour and filtered with a pressure filter. After completion of the filtration, the filter cake was dissolved in a mixture of 185 g deionized water and 262.1 g 75% H.sub.2SO.sub.4, stirred at 60° C. for 2 hours, cooled to 25° C. and filtered via suction filter. 1017 g of a clear and dark red colored filtrate were recovered, containing 43 g Ni, 43 g Co, 35.4 g Mn as well as less than 1 ppm Cu, 3 ppm Al, 2 ppm Fe, 5 ppm Zn, and 3 ppm Zr.

[0137] The resultant solution was excellently suited for the synthesis of a precursor for a cathode active material.

[0138] Overall recovery yields can be back-calculated from above values: Ni: 79%, Co: 82%, Mn: 83%, Li: 77%. Recovery yields for Ni, Co, and Mn are based on the metal contents in the final clear and dark red solution. Recovery of Li is based on the Li content of the combined two clear and colorless solutions obtained from the pressure filtration.