To enhance the fixed carbon content and recovery rate of flotation concentrates from low-grade natural flake graphite (NFG), this study employed synchronous ultrasonic flotation in combination with inorganic salt ion (NaCl) enhancement. Flotation experiments were conducted to investigate the synergistic effects of these two methods. X-ray photoelectron spectroscopy, contact angle analysis, laser particle-size analysis, Raman spectroscopy, infrared spectroscopy, zeta potential measurements, electron microscopy, and Debye length calculations confirmed that ultrasonic cavitation disrupted particle agglomeration and cleaned the graphite surface. This process generated fine micro-/nanobubbles with enhanced hydrophobicity, significantly improving concentrate recovery rates. NaCl addition compressed the double electric layer on particle surfaces and suppressed bubble coalescence, stabilizing the froth and promoting graphite–bubble adhesion, which markedly increased the fixed carbon content of the concentrate. The results demonstrated that through the integrated approach, low-grade NFG with an initial fixed carbon content of 7.98% was upgraded after rough processing to a concentrate containing 79.24% fixed carbon, with a recovery rate of 65.76%. These findings demonstrate that combining ultrasonic flotation with NaCl addition substantially improved both fixed carbon content and recovery rate in the concentrate. Overall, this study provides a novel technical pathway for the efficient utilization of low-grade graphite ore resources.

Recently, the amount of heat generated in devices has been increasing due to the miniaturization and high performance of electronic devices. Cu-graphite composites are emerging as a heat sink material, but its capability is limited due to the weak interface bonding between the two materials. To overcome these problems, Cu nanoparticles were deposited on a graphite flake surface by electroless plating to increase the interfacial bonds between Cu and graphite, and then composite materials were consolidated by spark plasma sintering. The Cu content was varied from 20 wt.% to 60 wt.% to investigate the effect of the graphite fraction and microstructure on thermal conductivity of the Cu-graphite composites. The highest thermal conductivity of 692 W m−1K−1 was achieved for the composite with 40 wt.% Cu. The measured coefficients of thermal expansion of the composites ranged from 5.36 × 10−6 to 3.06 × 10−6 K−1. We anticipate that the Cu-graphite composites have remarkable potential for heat dissipation applications in energy storage and electronics owing to their high thermal conductivity and low thermal expansion coefficient.

Two different types of graphite, such as flake graphite (FG) and spherical graphite (SG), were used as anode materials for a lithium-ion secondary battery in order to investigate their electrochemical performance. The FG particles were prepared by pulverizing natural graphite with a planetary mill. The SG particles were treated by immersing them in acid solutions or mixing them with various carbon additives. With a longer milling time, the particle size of the FG decreased. Since smaller particles allow more exposure of the edge planes toward the electrolyte, it could be possible for the FG anodes with longer milling time to deliver high reversible capacity; however, their initial efficiency was found to have decreased. The initial efficiency of SG anodes with acid treatments was about 90%, showing an over 20% higher value than that of FG anodes. With acid treatment, the discharge rate capability and the initial efficiency improved slightly. The electrochemical properties of the SG anodes improved slightly with carbon additives such as acetylene black (AB), Super P, Ketjen black, and carbon nanotubes. Furthermore, the cyclability was much improved due to the effect of the conductive bridge made by carbon additives such as AB and Super P.