Study on the Mechanism of Nanobubble-Coated Flake Graphite Ore Flotation in Short Circuits

Nanobubbles are an important means to enhance the flotation of fine refractory minerals. Generally, nanobubbles are preferentially adsorbed on mineral surfaces, which increases the hydrophobicity of the surfaces. For flake graphite ore, nanobubbles coated on graphite surfaces reduce the thickness of the hydrated film on the mineral surface and increase its hydrophobicity. In comparative experiments performed here, short flotation circuits of small flake graphite coated with nanobubbles achieved a 92.81% average fixed carbon grade of graphite concentrate, whereas conventional flotation circuits achieved an average of 88.15%. In addition, the concentrate recovery of short flotation circuits with nanobubbles was higher than that of conventional flotation circuits. This result shows that nanobubbles enhanced graphite particle flotation. Further, in this process, reducing the grinding duration is beneficial to avoid the overgrinding of concentrate, maintain the flake scale size of graphite, and improve the grade of the graphite concentrate.