flexible and efficient hydrometallurgical recycling of li...

Flexible and efficient hydrometallurgical recycling of Li-ion batteries of different chemistry

Gabriele LombardoPhD Student

Scheme of a Lithium Battery

LiCoO2LiMn2OLiNiO2

Dismantling

Mechanical pre-treatment

4

Current state of Li-ion batteries recycling

Pyrometallurgical treatment Hydrometallurgical treatment

Li

slag

List of critical raw materials for EU - 2017

Forecasts of global electric vehicle sales by 2030

SOURCE: BLOOMBERG NEW ENERGY FINANCE

3. Leaching

4. Solvent extraction

1. Pyrolysis

2. Mechanical Separation

Steps of the process being developed at Chalmers:

• Challenge:

The presence of polyvinylidene fluoride (PVDF)- the binder for the active material to be attached with the current collectors (thin copper and aluminium foils).

• It affects: 1. The mechanical separation process in which it obstructs the separation of the active material and

carbon (also called black mass) from the foils.2. The leaching process in which it prevents the contact of the leaching media with the material.

• Solution: Removal of PVDF by thermal methods (pyrolysis or incineration).

• Benefit: Utilization of carbon.

Pyrolysis

Pyrolysis

Carbon Metal oxides

Li,Co,Mn, NiCO2 and CO

+

+

Pyrolysis

Analysis of the unaltered batteryLiquid fraction (ICP analysis)

Cathode AnodeConc. (ppm) %W Conc. (ppm) %W

Al 282.4 7.06 0,8 0.00Co 233.0 5.83 0 0.00Cu 0 0.00 1417.5 35.44K 3.4 0.09 2,8 0.07Li 106.5 2.66 4.768 0.12

Mn 664.3 16.61 -Ni 228.4 5.71 0.14 0.089Si 2.9 0.07 2.7 0.07

Cathode AnodeConc. (ppm) %W Conc. (ppm) %W

Al 282.4 7.06 0,8 0.00Co 233.0 5.83 0 0.00Cu 0 0.00 1417.5 35.44K 3.4 0.09 2,8 0.07Li 106.5 2.66 4.768 0.12

Mn 664.3 16.61 -Ni 228.4 5.71 0.14 0.089Si 2.9 0.07 2.7 0.07

Analyzed elements

Li Co Cr Cu Al Mn Ni K Mo Si Y Na Fe Sn Mg

Setting of the process:

• Temperature: 400ºC, 500ºC, 600ºC, 700ºC.

• Time: 30 min, 1h, 1.5h.

• Flow of nitrogen: around 340 ml/min.

Pyrolysis

Variation of the weight of the samples before and after the thermal treatment.

The thermal treatment causes a variation of weight of the sample that is due by the formation ofvolatile species: the oxidation of graphite and other organic compound. The variation increased withthe rise of temperature and time.

Pyrolysis 400 500 600 700

30 min 1h 1.5 h 30 min 1h 1.5 h 30 min 1h 1.5 h 30 min 1h 1.5 h

Average delta % 6.89 9.17 11.28 9.26 11.90 15.65 9.32 12.51 18.94 11.40 15.54 22.18

By-productsWhite gas Oil (TAR)

etc

The formation of smoke happens in particular during the first 5-10 minutes of heating

It is possible that the smoke is produced by: Oxidation of the organic speces with formation of CO and CO2

the process of decomposition of PVDF that produces HF in gas phase.

Ftir analysis

Gas off analysis

Ftir analysis: CathodeComparison between a spectra in absorbance of a sample treated at 600°C per 2 and 5 minutes.

CO2

CO

HF

H2O

Ftir analysisCathode

• The peaks of the CO2 and CO are really intense, especially for the samples treated per 5 minutes. The oxidation of the carbon is due to the reaction with the metal salts present in the active material during the pyrolysis.

• C-F and H-F bond, whose presence is caused by the decomposition of the PVDF: the concentration of fluorides seems much more presence in the first minutes.

• Water vapor.

• Presence of organics specie as ketone and ester. The most probable origin has to be found in the evaporation of the electrolyte.

Anode

• The peaks for CO2 and CO, higher than in the cathode. There is a decreasing of the quantity of this specie in the gas off with time.

• Water vapor.

Mechanical Separation: Removal of black mass

Separation of black mass from aluminum and copper foils.

Improved purity of input material for hydrometallurgical treatment.

Simplification of solvent extraction process and decreasing of the energy demands for recovery of copper and aluminum.

Mechanical Separation: Removal of black mass

a b

a) sample holder of a ball mill; b) rotation plate with holders.

Setting of the process:

• Sample treated for 1.5 h at 600-700C.• Pieces of 16 cm2.• 10 minutes in the ball mill at 600 rpm.

The same treatment were applied on untreated samples in order to evaluate the efficiency. At the end of the rotation the powder was separated from the solid and weight.

Mechanical Separation: Removal of black mass

Thermal treatment followed by a mechanical one permit a separation of graphite and black mass from the metal layers with an efficiency of the 70%.

This is probably due to a decomposition at high temperature of the polymers as PVDF that working as glue between the metals layers and the active material.

The hydrometallurgical process can be significantly simplify.

TreatedUntreated

TreatedUntreated

XRD analysis and Thermodynamic consideration

Pyrolysis : XRD analysis

It was observed:

• The presence of metals in elemental form, as Li, Ni, Mn, Cu and Co.

• Mn3O4, Al2O3: aluminum and manganese react as reductant agents with the other metals.

• Li2O: lithium is extremely reactive and its oxidation is thermodynamically favorite at the conditions of the process.

• Increasing of the treatment temperature determines a decreasing of the quantity of the carbon in the sample.

Pyrolysis

It is possible have an idea of the variation in quantity of carbon, analyzing the XRD spectra of samples treated at different temperature.

The 26.5°, 44.8° and 54.9° peaks were identified as originated by the graphitic carbon present on the anode: the green curve (700°C) is much low then the others.

Pyrolysis : XRD analysis

LiCoO2

The XRD spectra shows the presence of Li2O, CoO2, Co3O4, CoO and Co, these last two has a stronger signals compared to the others.

1. 4LiCoO2(s) + 3 C(s) = 2 Li2O(s) + 4 Co(s) + 3 CO2(g)

2. 2LiCoO2 +3 CO(g) = Li2O + 2Co + 3CO2(g)

3. 4LiCoO2 + C = 2Li2O + 4CoO + CO2(g)

Pyrolysis : XRD analysis

LiMn2O4The XRD spectra shows the presence of the presence of Li2O, Li, Mn3O4 and Mn.

The reactions studied are:

1. LiMnO4 + 2C = Li + Mn + 2CO2(g)2. LiMnO4 + 4CO(g) = Li + Mn + 4CO2(g)3. 3LiMnO4 + 4C = 3Li + Mn3O4 + 4CO2(g)4. 3LiMnO4 + 8CO(g) = 3Li + Mn3O4 + 8CO2(g)5. 3LiMnO4 + 3,25C = 1,5Li2O + Mn3O4 + 3,25CO2(g)6. 3LiMnO4 + 6,5CO(g) = 1,5Li2O + Mn3O4 + 6,5CO2(g)7. 2LiMnO4 + 3,5C = Li2O + 2Mn + 3,5CO2(g)8. 2LiMnO4 + 7CO(g) = Li2O + 2Mn + 7CO2(g)

T (°C)ΔG (kJ/mol)

1 2 3 4 5 6 7 8300 -137,78 -279,65 -810,95 -1094,70 -1302,06 -1532,60 -602,96 -851,24400 -174,10 -280,21 -885,93 -1098,15 -1355,71 -1528,14 -661,38 -847,08500 -212,27 -282,77 -966,66 -1107,67 -1415,16 -1529,73 -723,53 -846,91600 -252,07 -287,15 -1052,50 -1122,64 -1479,82 -1536,81 -789,03 -850,40700 -293,36 -293,20 -1142,93 -1142,60 -1549,23 -1548,97 -857,59 -857,31800 -336,21 -301,01 -1237,54 -1167,13 -1623,04 -1565,83 -929,43 -867,82

Pyrolysis : XRD analysis

LiNiO2

1. 2LiNiO2 +3 CO(g) = Li2O + 2Ni + 3CO2(g)2. 4LiNiO2 + C = 2Li2O + 4NiO + CO2(g)

The XRD spectra shows the presence of Li2O, Li, NiO and Ni.

ConclusionIn conclusion, the thermodynamic considerations show that the reactions between graphite, the reductive atmosphere present in the system and the salts in the black mass are spontaneous in the conditions of the process and their ΔG become more negative increasing the temperature.

Leaching and Solvent Extraction

Leaching - Several parameters such as different leaching agents, temperature, and solid to liquid ration are

studied in the leaching process. The aim is to develop efficient and more environmentally friendly leaching

procedure applicable for Li-ion batteries based on different chemistries.

Solvent extraction process: In the process of metal ions recovery different extractants are used to determine

optimal parameters flexible for differences in the leachates coming from previous step.

The developed processes will be scaled up in pilot scale leaching reactors and mixer settlers.

Leaching

Solvent extraction

Leaching

Cobalt leaching after thermal treatment: Lithium leaching after thermal treatment:

1M HCl – no reduction agent

Extraction (Mn) CYANEX 272/572 in kerosene Raffinate (Li, Co, Ni)

Scrubbing Scrubbing product (Mn, Ni)

Stripping

Extraction (Ni) raffinate (Li)

Stripping stripping product (Ni)

Li precipitationNa2CO3

MnCl2

HCl Stripping product ( Mn)

HCl

Li2CO3

CYANEX 272/572 in kerosene

Solid/ Liquid separation

Feed

Co precipitationNaClO

Co2O3Solid/ Liquid separation

Raffinate (Li, Ni)

Extraction (Mn) CYANEX 272/572 in kerosene Raffinate (Li, Co, Ni)

Scrubbing Scrubbing product (Mn, Ni)

Stripping

MnCl2

HCl Stripping product ( Mn)

Feed

Co precipitationNaClO

Co2O3Solid/ Liquid separation

Raffinate (Li, Ni)

Extraction (Ni) raffinate (Li)

Stripping stripping product (Ni)HCl

CYANEX 272/572 in kerosene

Li precipitationNa2CO3

Li2CO3Solid/ Liquid separation

S t o c k s o l u t i o n : M n C l 2 , C o C l 2 , N i C l 2 , L i C l i n H C l .S o l i d - l i q u i d r a t i o : 1 / 5 0 .T h e e f f i c i e n c y o f 2 a c i d i c e x t r a c t a n t s w a s c o m p e r e d : C y a n e x 2 7 2 a n d C y a n e x 5 7 2 , b o t h a t1 M .

T h e r e s u l t s r e p r e s e n t t h e v a l u e s o b t a i n e d a t p H e q u i l i b r i u m .

• T h e d i f f e r e n c e b e t w e e n t h e 2 e x t r a c t a n t s i s n o t s i g n i f i c a n t .

• L i r e m a i n s i n t h e a q u e o u s p h a s e t h r o u g h o u t t h e p H r a n g e i n v e s t i g a t e d a n d f o r b o t hC y a n e x 2 7 2 a n d 5 7 2 . T h i s g a v e a s t h e p o s s i b i l i t y t o r e c o v e r t h a t b y p r e c i p i t a t i o n .

• N i r e m a n s i n t h e h y d r o c h l o r i c a c i d s o l u t i o n a t p H 6 , i n s t e a d C o a n d M n r e s u l t e da l r e a d y p a r t i a l l y e x t r a c t e d i n o r g a n i c p h a s e a t p H 4 .

Solvent Extraction

http://www.circularmaterialsconference.se/

www.ceb2018.org

Circular Economy of Battery Production and Recycling

Gothenburg, 24-26th of September 2018

37

Thank you for your attention!

for more information contact:

Matina Patranikova:martina.petranikova@chalmers.se

Gabriele Lombardo: gablom@chalmers.se

Solvent Extraction and Precipitation

•Mn recovered by precipitation by drop-wise adding 0.5 mol L of 1 KMnO4 solution to leaching liquor, pH 2.

•Cyanex 572 or 272: separation of cobalt and nickel from Li.

•Na2CO3 to precipitate Li as LiCO3

•Co recovered by oxidative precipitation with NaClO at pH 3.

•Ni recovered by precipitation with sodium hydroxide to achieve pH 11 in a second step.

Aims of the project• Study the possibilities of removal of organic compounds from spent lithium ion

accumulators through thermal pre treatment.

• Study how the pyrolysis and combustion affects chemical and phase composition of the material.

• Characterization of by-products (off-gas, tar, etc.).

• Study the possibilities to separate electrode foils from active material.

• Development of hydrometallurgical technology for a metal recovery from spent LiB with emphasis to accommodate the process to the different chemistries of LiB.

• Testing the proposed technology in a pilot plant scale equipment to simulate conditions expected in a real plant scale.

Dismantling

Lithium battery cell SPA The weight of the entire cell is 480 g, it is composed by 19 layers of copper and 18 layers of aluminum and the plastic cover weight 23g.

single layer all layer % weight

Anode layer of copper 3.02 ±0.04 g 57.1 g 11.9

black mass 6.10 ±0.2 g 115.9 g 24.2

Cathode

layer of aluminum 2 ± 0.2 g 36.3 g 7.5 black mass 11.8 ±1 g 212.4 g 44.2

separator 2.33 ± 0.03 g 42.2 g 8.8

• Equal number of cathodes and anodes to obtain homogeneus samples.

• Dissolution in aqua regia (80ºC; 5h).

• Filtration Liquid fraction (ICP analysis)

Undissolved fraction (XRD analysis)

Analysis of the unaltered battery

Analysis of the unaltered batteryUndissolved fraction (XRD analysis)

Average %w undissolved fraction 20.8%

• Cathode : polymers that constitute the separator, PVDF,Al2O3.

• Anode shows that the undissolved material is constituted essentially by graphite.

ICP analysis

0

100

200

300

400

500

600

30 min 1 h 1.5 h

ppm

t

Mn

400 C500 C600C700 C

0

50

100

150

200

250

300

350

30 min 1 h 1.5 h

ppm

t

Ni 400

500

600

700

0

50

100

150

200

250

300

30 min 1 h 1.5 h

ppm

t

Co

400

500

600

700

0

20

40

60

80

100

120

140

30 min 1 h 1.5 h

ppm

t

Li 400

500

600

700

Graphic representation of the concentration in ppm of the element detected in the acid solutions obtained dissolving the samples pyrolyzed at different temperature and time

Pyrolysis: ICP analysis

The relative abundance of each element increase between 60% ( Cu, Ni) an 100% ( Mn, Co, Li, Al).

0

200

400

600

800

30 min 1 h

ppm

t

Mn 400 C

500 C

600 C

700 C

0

100

200

300

400

500

30 min 1 h

ppm

t

Ni 400 C

500 C

600 C

700 C

0

100

200

300

30 min 1 h

ppm

t

Co 400 C

500 C

600 C

700 C

0

50

100

150

200

30 min 1 h

ppm

t

Li 400 C

500 C

600 C

700 C

Graphic representation of the concentration in ppm of the elements detected in the acid solutions obtained dissolving the samples thermal treated at different temperature and time.

Combustion : ICP analysis