-25-
provided by the technician, and click OK to start the upgrade.
10. Battery recovery
Aluminum, copper, lithium, iron and other metal materials are recovered from discarded LiFePO4
batteries by advanced hydrometallurgical process, and the comprehensive recovery efficiency can
reach 80%. The specific process steps are as follows:
10.1 Recovery process and steps of cathode materials
Aluminum foil as collector is amphoteric metal. Firstly, it is dissolved in NaOH alkali solution to make
aluminum enter the solution in the form of NaAlO
2
. After filtration, the filtrate is neutralized with
sulfuric acid solution and precipitated to obtain Al (OH)
3
. When the pH value is above 9.0, most of the
aluminum precipitates, and the obtained Al (OH)
3
can reach the level of chemical purity after
analysis.
The filter residue is dissolved with sulfuric acid and hydrogen peroxide, so that lithium iron phosphate
enters the solution in the form of Fe
2
(SO
4
)
3
and Li
2
SO
4
, and is separated from carbon black and
carbon coated on the surface of lithium iron phosphate. After filtration and separation, the pH value
of the filtrate is adjusted with NaOH and ammonia water. First, iron is precipitated with Fe (OH)
3
, and
the remaining solution is precipitated with saturated Na
2
CO
3
solution at 90
℃
.
Since FePO
4
is slightly dissolved in nitric acid, the filter residue is dissolved with nitric acid and
hydrogen peroxide, which directly precipitates FePO
4
, separates impurities such as carbon black
from acid solution, leaches Fe (OH)
3
from filter residue respectively, and precipitates Li
2
CO
3
with
saturated Na
2
CO
3
solution at 90
℃
.
