&Pre-treatment stage:
Disassembly – Discharge – Crushing – Pyrolysis – Sorting
# Dismantling- firstly, the battery pack is dismantled into modules, due to the different
specificationsof the battery pack, at present, most of the enterprisesmainly dismantle
the battery pack manually, with a low degree of automation.
# Discharge: Since some power is still left in the waste battery, in order to ensure the
safety of recyclingproduction, it needs to be fully discharged before crushing.There are
mainly physical and chemical methods for safe discharge, the physical method is discharged
by means of external resistance; the chemical method is to release the residual electricity
through electrolysis of conductive solution, usually with NaCl solution as the auxiliary material.
Depending on the shape of the battery, the discharge method also varies. Smaller soft pack
batteries and cylindrical batteries usually use the chemical discharge method, while square
batteries mostly use the physical discharge method. The chemical method will produce sewage
and exhaust gas, the physical method can collect electrical energy (experimental stage),the
economy is better than the chemical method
#Crushing: usually using mechanical equipment to separate the electrode material from other
substances,due to the battery crushing process will produce heat release, so easy to burn,
explosion, so some companies use nitrogen in the crushing process to protect the crushing security
#Pyrolysis: use high temperature to burn off the electrolyte, diaphragm, binder and other organic
materials,the temperature of pyrolysis usually depends on the enterprise’s own ability to control
the temperature of the kiln, the higher the temperature the more conducive to the burning off of the
organic materials to enhance the recovery yield, but at the same time more than 700 ° C aluminum
will be directly and oxygen to occur in the thermal reaction of aluminum,resulting in safety accidents.
# Sorting: Use flotation, magnetic separation, gravity separation and other ways to sieveout aluminum,
copper,iron, graphite and other substances, to get black powder into the wet metallurgy stage for further
processing.
& Wet metallurgy stage :
Acid leaching–Demixing–Extraction (In detail as follow picture 1)
#Acid leaching: two-step leaching method, the black powder and 98% concentrated sulfuric acid
according to a certain ratio of mixing, the use of hot steam heated to 50 ° C – 70 ° C, in order to
enhance the efficiency of the reaction, and at the same time to add H2O2 as a reductant, which can
enhance the effect of the leaching of metals.
#Removal of impurities: iron powder, Ca(OH)2, H2O2, NaOH, Na2CO3 and other auxiliary materials
need to be used to remove copper, iron, aluminum, calcium, magnesium and other impurities, to enhance
the product yield.
# Extraction: P204 and P507 are usually used to extract nickel sulfate, manganese sulfate,cobalt sulfate
solution,after which lithium carbonate is extracted by adjusting the PH value,carbonization and pyrolysis,
precipitation and other process steps.
Picture 1