Study On The Physical Separation And Recovery Process Of Spent Lithium Ion Power Batteries

It was predicted that the cumulative quantity of discard lithium ion power batteries in China would reach 500,000 tons by 2020.The battery contains high value metal and harmful substances.Recycling and reusing the batteries can not only recycle the resources,but also reduce environmental pollution.At present,the recovery process mainly includes physical separation and metallurgical processing.With the simple crushing way and single physical separation,physical separation method lead to the result of low purity and recovery rate in the recycling process.To solve the problem,we improved the separation process based on regular crushing,with the combination of gravity separation,eddy current separation and heat treatment.Through the separation process,the anode materials,membrane,copper foil,aluminum foil,and the cathode materials was recycled.The research object was the spent ternary lithium ion power batteries which had good application prospect.The regular crushing method was applied to break the battery into the same size according to the characteristic of shape of battery.The effect of the crushing particle size on the loss rate of cathode materials showed the best crushing particles size was 16 mm x 16 mm.After regular crushing,the anode materials was recovered by soaked,stirred and screened due to the solubility of anode binder in water.The loss rate of anode materials reached 99.43%in the best condition of the stirred speed was 450 r/min,mixed time was 3 min,liquid-solid ratio was 15.A new gravity separator was designed to recycle the membrane according to the specific gravity of membrane was lower than copper foil and the cathode,The recovery rate of membrane was 99.84%under the best condition that the gravity separator stirred speed was 250 r/min.The eddy current separation method was used to separate copper foil and cathode on account of their electrode conductivity.The recovery rate of cathode and Cu foil were 88.19%and 63.13%under the best conditions that the belt speed was 0.8 m/s,magnetic roller speed was 1200 r/min,and the baffle height was minimum.The heat treatment was used to pyrolyze PVDF which was the binder between the cathode materials and aluminum foil.The cathode materials and Al foil were separated after water quenching,scrubbing and screening.The loss rate of cathode materials was 96.60%under the best condition that the oxygen roasted temperature was 500 ℃,the heat treatment time was 40 min.The graphite was recycled from anode materials to regenerate the anode materials.The recycled cathode material was 523 ternary active materials mainly and contained trace amounts of Cu and Al,which could be used for the preparation of ternary precursor and production of metal products.The properties of the membrane were basically consistent after recovery,which could be used for membrane regeneration.The recycled copper foil and aluminum foil products could be used for reproducing the Cu foil and Al foil of the battery.