THESIS
2019
Abstract
In recent years, the rapid development of battery industry has increased a lot in demand for
lithium ion batteries. Due to the light weight, high energy capacity and good performance of LiNi
0.8Co
0.15Al
0.05O
2 (NCA) and LiNi
1-x-yMn
xCo
yO
2 (NMC) cathode materials-based lithium
ion batteries, the usage of these cathode materials has rapidly increased. The recycle of these
cathode materials has attracted a lot of attentions because of the large quantity and
environmental conservation. Oxalic acid is a good leaching agent for these two cathode
materials, but the subsequent process needs further study. In this research, the oxalates obtained
from oxalic acid leaching of NCA and NMC cathode materials will be investigated to recycle
each metal element.
The acid baking and the Co oxidation...[
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In recent years, the rapid development of battery industry has increased a lot in demand for
lithium ion batteries. Due to the light weight, high energy capacity and good performance of LiNi
0.8Co
0.15Al
0.05O
2 (NCA) and LiNi
1-x-yMn
xCo
yO
2 (NMC) cathode materials-based lithium
ion batteries, the usage of these cathode materials has rapidly increased. The recycle of these
cathode materials has attracted a lot of attentions because of the large quantity and
environmental conservation. Oxalic acid is a good leaching agent for these two cathode
materials, but the subsequent process needs further study. In this research, the oxalates obtained
from oxalic acid leaching of NCA and NMC cathode materials will be investigated to recycle
each metal element.
The acid baking and the Co oxidation processes were selected and optimized for the
treatment of oxalates obtained by oxalic acid leaching from NCA cathode material. In the acid
baking process, the effects of baking time, sulfuric acid dosage and baking temperature on the
recovery of Ni/Co were investigated. In the Co oxidation process, the effects of reaction time,
S/L ratio, molar ratios of sodium persulfate to Co, reaction temperature and pH on Co oxidation
were studied. The total Co and Ni recovery reached 97%. The dissolution of NMC oxalates
(together with Mn oxidation) and the solvent extraction processes were selected and optimized
for the treatment of oxalates obtained by oxalic acid leaching from NMC cathode material. In
the dissolution of NMC oxalates process, the effects of reaction time, S/L ratio, molar ratio of
sodium persulfate to oxalates, reaction temperature and pH were investigated. In the solvent
extraction process, the effects of extractant concentration, saponification ratio and initial pH on
Co and Ni extraction were studied. The total Mn, Co and Ni recovery were 95%, 87% and 94%,
respectively.
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