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A novel approach to recycling of copper and aluminum fragments in the crushed products of spent lithium iron phosphate batteries was proposed to achieve their eco-friendly processing. The model of pneumatic separation that determines the optimal airflow velocity was established using aerodynamics. The influence of the airflow velocity, and the density and thickness, and their ratios, of the aluminum and copper fragments on pneumatic separation were evaluated. The results show that the optimal airflow velocities of copper and aluminum fragments with and without the electrode materials are 3.27m/s and 1.67m/s, respectively. The accuracy and reliability of the present model was verified using a pneumatic separation experiment. It is concluded that graded pneumatic separation is unnecessary for the crushed particle size more than 9 mm. The experimentally determined optimal airflow velocity of the copper and aluminum fragments with and without the electrode materials is 3.3m/s and 1.7m/s, respectively. The mass fractions of the copper and aluminum fragments upon removal of the electrode materials after pneumatic separation are 97% and 96%, respectively, and both with the electrode material achieve 97.0%. The theoretically obtained optimal airflow velocities have good agreements with the experimentally obtained ones.

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The recycling processes of spent lithium iron phosphate batteries comprise thermal, wet, and biological and mechanical treatments. Limited research has been conducted on the combined mechanical process recycling technology and such works are limited to the separation of metal and non-metal materials, which belongs to mechanical recovery. In this article the combined mechanical process recycling technology of spent lithium iron phosphate batteries and the separation of metals has been investigated. The spent lithium iron phosphate batteries monomer with the completely discharged electrolyte was subjected to perforation discharge. The shell was directly recycled and the inner core was directly separated into a positive electrode piece, dissepiment, and negative electrode piece. The dissociation rate of the positive and negative materials reached 100.0% after crushing when the temperature and time reached 300 °C and 120 min. The crushed products were collected and sequentially sieved after the low-temperature thermal treatment. Then, nonferrous metals (copper and aluminium) were separated from the crushed spent lithium iron phosphate batteries by eddy current separation with particle size −4 + 0.4. The optimised operation parameters of eddy current separation were fed at speeds of 40 r min-1, and the rotation speed of the magnetic field was 800 r min-1. The nonferrous metals of copper and aluminium were separated by the method of pneumatic separation. The optimal air speed was 0.34 m s-1 for the particle-size −1.6 + 0.4 mm and 12.85–14.23 m s-1 for the particle-size −4 + 1.6 mm. The present recycling process is eco-friendly and highly efficient and produces little waste.

A novel and highly active zeolite Y/ZSM-5 composite zeolite (CZ)-supported nickel catalyst (Ni/CZ with 10% of Ni loading) was prepared by modified deposition−precipitation to uniformly disperse Ni nanoparticles (NNPs) onto CZ. Hecaogou subbituminous coal was exhaustively extracted with isometric carbon disulfide/acetone mixed solvent to afford the extractable portion and inextractable portion (IEP). Ethanol-soluble portion (ESP) was obtained by ethanolyzing the IEP at 300 °C and subjected to catalytic hydroconversion (CHC) over Ni 10% /CZ at 160 °C to afford catalytically hydroconverted ESP (CHCESP). Both ESP and CHCESP were analyzed with a Fourier transform infrared spectrometer, gas chromatograph/mass spectrometer (GC/ MS), and quadrupole exactive orbitrap mass spectrometer. The results show that the relative contents (RCs) of both chain alkanes and hydroarenes in CHCESP are significantly higher than those in ESP and cyclanes and alkenes were only detected in CHCESP, while the RCs of both arenes and oxygen-containing organic compounds in CHCESP are much lower than those in ESP and nitrogen-and/or sulfur-containing organic compounds were only detected in ESP with GC/MS. According to the CHC of oxybis(methylene)dibenzene (OBMDB), Ni 10% /CZ can effectively activate H 2 to biatomic active hydrogen (H•••H) and the resulting H•••H was heterolytically split into an immobile H − attached on Ni/CZ and a mobile H + . H + transfers to an oxygen atom (OA) in OBMDB and cleaves the C−O bridged bond to produce phenylmethanol (PM) and benzylium, followed by H − abstraction from the Ni/CZ surface by benzylium to form toluene. H + transfer to the OA in PM also leads to the cleavage of the C−O bond in PM to produce H 2 O and benzylium, which abstracts H − from the Ni/CZ surface to yield toluene. H•••H transfer to the benzene ring in toluene generates methylcyclohexane. Therefore, Ni 10% /CZ catalyzes both H + and H•••H transfer. In addition, it proved to be stable for the CHC of OBMDB after 3 cycles.

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With the rapid development of the electric vehicle market since 2012, lithium-iron phosphate (LFP) batteries face retirement intensively. Numerous LFP batteries have been generated given their short service life. Thus, recycling spent LFP batteries is crucial. However, published information on the recovery technology of spent LFP batteries is minimal. Traditional separators and separation theories of recovering technologies were unsuitable for guiding the separation process of recovering metals from spent LFP batteries. The separation rate of the current method for recovering spent LFP batteries was rather low. Furthermore, some wastewater was produced. In this study, spent LFP batteries were dismantled into individual parts of aluminium shells, cathode slices, polymer diaphragms and anode slices. The anode pieces were scraped to separate copper foil and anode powder. The cathode pieces were thermally treated to reduce adhesion between the cathode powder and the aluminium foil. The dissociation rate of the cathode slices reached 100% after crushing when the temperature and time reached 300℃ and 120 min, respectively. Eddy current separation was performed to separate nonferrous metals (aluminium) from aluminium and LFP mixture. The optimized operation parameters for the eddy current separation were feeding speed of 1 m/s and magnetic field rotation speed of 4 m/s. The separation rate of the eddy current separation reached 100%. Mass balance of the recovered materials was conducted. Results showed that the recovery rate of spent LFP can reach 92.52%. This study established a green and full material recovery process for spent LFP batteries.