This paper investigates the reactions involved when LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC 811), which is one of the most promising positive electrodes for the next generation of lithium-ion batteries, is leached by hydrochloric acid.This study shows that the leaching behaviour of lithium is quite different than those observed for nickel, cobalt and manganese contained in NMC 811 since lithium dissolution is faster than those observed for nickel, cobalt and manganese. Analysis of leaching kinetic data evidenced that NMC 811 dissolution occurs in two steps. In the first step, NMC is transformed into a new phase which contains less lithium (2.8 < n < 3.6): 1 st step:1 À 1 2n Cl 2;ðgÞ . Finally, the overall reaction of NMC 811 leaching by hydrochloric acid can be written as: 2LiMO 2,(s) + 8HCl (l) # 2LiCl (l) + 2MCl 2,(l) + 4H 2 O (l) + Cl 2,(g) .
Lithium-ion batteries (LIBs) are widely used everywhere today, and their recycling is very important. This paper addresses the recovery of metals from NMC111 (LiNi1/3Mn1/3Co1/3O2) cathodic materials by leaching followed by antisolvent precipitation. Ultrasound-assisted leaching of the cathodic material was performed in 1.5 mol L−1 citric acid at 50 °C and at a solid-to-liquid ratio of 20 g/L. Nickel(II), manganese(II) and cobalt(II) were precipitated from the leach liquor as citrates at 25 °C by adding an antisolvent (acetone or ethanol). No lithium(I) precipitation occurred under the experimental conditions, allowing for lithium separation. The precipitation efficiencies of manganese(II), cobalt(II) and nickel(II) decreased according to the order Mn > Co > Ni. The precipitation efficiency increased when a greater volume of antisolvent to the leachate was used. A smaller volume of acetone than ethanol was needed to reach the same precipitation efficiency in accordance with the difference in the dielectric constants of ethanol and acetone and their associated solubility constants. After adding two volumes of acetone into one volume of the leach liquor, 99.7% manganese, 97.0% cobalt and 86.9% nickel were recovered after 120 h, leaving lithium in the liquid phase. The metal citrates were converted into metal oxides by calcination at 900 °C.
Lithium-ion
batteries (LIBs) are widely used in industry today
and their recycling turns out to be very important. This paper is
focused on the selective recovery of cobalt(II), nickel(II), and manganese(II)
contained in a leach solution obtained by digesting a cathodic material
from spent LIB (NMC111, LiNi1/3Mn1/3Co1/3O2) with hydrochloric acid. After leaching the cathodic
material, cobalt(II) was selectively extracted toward manganese(II)
by liquid–liquid extraction with 0.4 mol L–1 Alamine 336 (tri-octyl/decyl amine) diluted in kerosene modified
using 10% (vol) 1-dodecanol at an optimized phase volume ratio between
the organic phase and the aqueous phase of O/A = 1/2. Afterward, manganese(II)
was extracted from the cobalt-depleted aqueous phase using 0.7 mol
L–1 Alamine 336 diluted in kerosene modified with
10% (vol) 1-dodecanol at O/A = 2. The resulting nickel(II)-lithium(I)
acidic solution was neutralized at pH 8 with sodium hydroxide in order
to precipitate almost all the nickel as nickel(II) hydroxide. The
process can recover more than 99.9% cobalt(II) and produce an aqueous
phase for further precipitation step containing 94.6% cobalt(II) and
5.4% manganese(II). Manganese(II) was recovered from the cobalt-depleted
stream to produce manganese(II) solution, the purity of which was
greater than 99.9%. Furthermore, this process allowed extracting more
than 97.0% nickel(II) from the leach solution, which was precipitated
as nickel(II) hydroxide. This precipitate contained 55.6% nickel(II),
7.85% chloride, 2.42% sodium(I), and 0.02% lithium(I). The effluent
containing 0.649 g L–1 lithium(I) and 79.0 g L–1 sodium(I) could be processed by appropriate solvent
extraction with Cyanex 936, that is, a phosphorus-based extractant
specifically formulated for lithium–sodium separation from
chloride media such as brines, or by implementing a precipitation
stage to selectively recover lithium toward sodium.
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