The improper disposal of retired lithium batteries will cause environmental pollution and a waste of resources. In this study, a waste lithium iron phosphate battery was used as a raw material, and cathode and metal materials in the battery were separated and recovered by mechanical crushing and electrostatic separation technology. The effects on material electrostatic separation of separation parameters such as the crushing particle size, the voltage of the static electrode, and the rotating speed of the grounding rotor were all studied combined with trajectory simulation and separation experiments. The results show that the crushing particle size of the material has the most significant impact on the separation effect, and the material separation effect primarily occurs in the range of 0.2–2.0 mm particle sizes. When the voltage of the static electrode is 30 kV, the rotating speed of the grounded rotor is 60 r/min, and the particle size is 0.4–0.8 mm, and the recovery rates for aluminum, copper, and lithium iron phosphate reach 93.2%, 91.1%, and 97.1%, respectively. In the recovery process for waste lithium batteries, using electrostatic separation technology instead of high-temperature roasting or chemical leaching can effectively improve the separation efficiency and reduce secondary pollution.
The automated fiber placement (AFP) process faces a crucial challenge: the emergence of out-of-plane buckling in thermoplastic prepreg tows during steering, significantly impeding the quality of composite layup. In response, this study introduces a novel approach: the development of equations for wrinkle-free fiber placement within composite pressure vessels. The investigation encompasses a detailed analysis of prepreg trajectories in relation to shell geometry, accompanied by an in-depth understanding of the underlying causes of wrinkling on dome surfaces. Moreover, a comprehensive model for shell coverage, grounded in placement parameters, is meticulously established. To validate the approach, a simulation tool is devised to calculate press roller motions, ensuring the uniform fiber dispersion on the mandrel and achieving flawless coverage of the shell without wrinkles. This innovative strategy not only optimizes the AFP process for composite layup but also remarkably enhances the overall quality of composite shells. As such, this research carries significant implications for the advancement of composite manufacturing techniques and the concurrent improvement in material performance.
26 April 2023 in Journal of Material Cycles and Waste Management
Currently, there is limited research on the in situ forming process of thermoplastic prepreg tape winding, and the unclear impact of process parameters on mechanical properties during manufacturing is becoming increasingly prominent. The study aimed to investigate the influence of process parameters on the mechanical properties of thermoplastic composite materials (CFRP) using laser-assisted CF/PPS winding forming technology. The melting point and decomposition temperature of CF/PPS materials were determined using DSC and TGA instruments, and based on the operating parameters of the laser-assisted winding equipment, the process parameter range for this fabrication technology was designed. A numerical model for the temperature of laser-heated CF/PPS prepreg was established, and based on the filament winding process setup, the heating temperature and tensile strength were simulated and tested. The effects of process parameters on the heating temperature of the prepreg and the tensile strength of NOL rings were then analyzed. The non-dominated sorting genetic algorithm (NSGA-II) was employed to globally optimize the process parameters, aiming to maximize winding rate and tensile strength. The results indicated that core mold temperature, winding rate, laser power, and their interactions significantly affected mechanical properties. The optimal settings were 90 °C, 418.6 mm/s, and 525 W, achieving a maximum tensile strength of 2571.51 MPa. This study provides valuable insights into enhancing the forming efficiency of CF/PPS-reinforced high-performance engineering thermoplastic composites.