Abstract: The disposal of coal gasification fine slag (CGFS) is a challenging issue in the coal chemical industry. Large quantities of this solid waste not only occupy land resources but also pose risks to soil and groundwater safety; therefore, landfill disposal is no longer a sustainable option, and achieving efficient separation of carbon and ash from this residue is becoming increasingly critical. In this study, a jet cavitationenhanced flotation process is proposed, and efficient recovery of residual carbon is achieved by investigating the operating parameters of the jet equipment. First, the physicochemical properties of the gasification fine slag were characterized using proximate analysis, ultimate analysis, particle size/density distribution, Xray diffraction (XRD), Fouriertransform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results revealed the presence of polar oxygencontaining functional groups on the particle surface, poor natural hydrophobicity, and an embedded carbonash structure, all of which increase the difficulty of liberation and subsequent separation. Given the fine particle size and welldeveloped pore structure of the residual carbon in CGFS, this study proposes and systematically investigates a micronano bubbleenhanced flotation process based on jet cavitation. Regarding the operating parameters of jet flotation, the effects of jet pressure, aeration rate, and jet intervention timing on separation performance were examined. The results show that the optimal separation is achieved at a jet pressure of 0.3 MPa, an aeration rate of 0.633 m3/h (gastoliquid ratio of 1:1), and with the jet initiated after pulp conditioning (at Node II). Under these conditions, with kerosene dosage of 3.5 kg/t and secoctyl alcohol dosage of 2 kg/t, the combustible recovery is increased by 22.92%. For the flotation mechanism, collector dispersion experiments confirmed that a jet pressure of 0.3 MPa generates the strongest turbulent shear and cavitation, effectively emulsifying kerosene into micronsized oil droplets with a distinct bimodal size distribution, thereby improving collection efficiency. Singlebubble attachment experiments demonstrated that the micronano bubble environment significantly shortens the induction time between bubbles and residual carbon particles and greatly increases the attachment amount of mineralized bubbles. Contact angle and residual carbon agglomeration experiments verified that micronano bubbles markedly improve the surface wettability of residual carbon and promote the formation of stable agglomerates of fine residual carbon particles via gas bridges. Molecular dynamics (MD) simulations further revealed the “selective interfacial adhesion” mechanism of micronano bubbles at the microscopic level: on hydrophobic residual carbon surfaces, micronano bubbles rapidly rupture the water film and spontaneously spread, forming a stable adsorption structure, whereas on hydrophilic ash surfaces, bubble adhesion is hindered by a stable hydration layer. Overall, this study not only elucidates the physicochemical essence of micronano bubbleenhanced flotation of gasification fine slag, but also provides theoretical support for the resource utilization of gasification fine slag as a secondary material in industrial practice, and offers important technical support for implementing new policies on solid waste prevention and control and for establishing a green closedloop circulation system.