Amid the comprehensive utilization of coal gasification fine slag (CGFS), its abundant metallic elements (Al, Fe, Ca, Mg) remain underutilized, yet these are key constituents of layered double hydroxides (LDHs). This study innovatively proposes using CGFS-derived metals to synthesize CO2-adsorptive LDH for resource enhancement of solid waste. The effect of ultrasonic acid leaching on metal separation from CGFS's ash-rich fraction (LFS) was analyzed, the conditions for synthesizing LDHs using leachate as feedstock were optimized, the CGFS-based LDHs were characterized, and their CO2 adsorption capacity, cycling stability, and adsorption behavior were evaluated. Results show that factors affecting leaching rates follow HCl concentration > ultrasonic power > leaching time > leaching temperature, the leaching rates for Al, Fe, and Ca under optimized conditions were 76.68%, 80.96%, and 80.35%, respectively. Saucer-shaped LDHs via alkaline hydrothermal method and nanosheet-shaped LDHs via urea hydrothermal method were synthesized, with the latter having a multi-level pore structure including ultramicropores, micropores, and mesopores. This LDH exhibits a CO2 adsorption capacity (0.65 mmol/g) comparable to that of LDHs synthesized from pure reagents, with excellent cycling stability, via a hybrid mechanism of basic site-dominated chemisorption and multi-level pore-facilitated physisorption. The study establishes the synthesis-structure-performance relationship and three-stage mechanism of element separation, LDH synthesis, CO2 adsorption of CGFS-based LDHs, proposes approaches to boost its CO2 adsorption performance, which provides a novel pathway for CGFS's high-value utilization and carbon reduction, advancing clean coal use and carbon-neutral technologies.

This paper investigates the enhancement of Shengli lignite flotation using oxidized diesel and explores the underlying mechanism from the aspect of interfacial interaction via molecular dynamics (MD) simulations. It indicated that the flotation of coal sample was significantly enhanced by the oxidized diesel, and a clean coal yield of 52.04 % was obtained at 2 kg/t of oxidized diesel, which is better than the flotation index consuming 100 kg/t of conventional diesel. XPS and FTIR analyses indicated that the enhanced flotation of the coal sample was attributed to the effective coverage of hydrophilic sites on the lignite surface by the oxidized diesel. This significantly improved the lignite surface hydrophobicity, with the contact angle increasing from 60 degrees up to 138 degrees. Furthermore, MD simulations demonstrated that the polar component of oxidized diesel adsorbed on the hydrophilic sites of coal surface via the bridging of water molecules. The nonpolar component of oxidized diesel was adsorbed onto the hydrophobic region through hydrophobic bonds. The synergistic adsorption of polar and nonpolar components resulted in a thicker adsorption layer (12.20 & Aring;) of oxidized diesel on the coal surface. This made the lignite more effectively repel water molecules away the coal surface from 66.8-77.8 & Aring; to 71.5-82.0 & Aring;, enhancing the coal surface hydrophobicity. This research may provide valuable insights for addressing technical challenges in low-rank coal flotation.

As one of the main copper oxide minerals, the strong surface hydrophilicity induces the low recovery of malachite and decreases the utilization efficiency of copper metal. In this work, the interface hydration structure of malachite and regulation mechanism by bis(2-ethylhexyl)phosphate (D2EHPA) were revealed via density functional theory (DFT) calculations, molecular dynamics (MD) simulations, X-ray photoelectron spectroscopy (XPS) analysis, contact angle and Zeta potential measurements. Flotation tests and contact angle measurements showed that D2EHPA exhibited excellent concentration selectivity for malachite against muscovite and quartz, enhanced the malachite recovery to 90.65 % with the dosage of 50 mg/L at pH 7.0, and the contact angle of malachite increased from 23.0 degrees to 111 degrees. Zeta potential analysis confirmed the selective adsorption of D2EHPA on malachite surface, electrostatic attraction occurred between D2EHPA and malachite surface when pH < 8.0. XPS analysis and DFT calculations further confirmed the adsorption of D2EHPA on malachite surface. Moreover, the adsorption of D2EHPA mainly via the chemical bonding between O1 (P=O), O2 (P-OH) and the Cu on malachite surface. MD simulations revealed that the average D2EHPA molecule interaction energy with malachite (-2 0 1) surface was -36.522 kJ/mol, increased the interaction energy of H2O on malachite (-2 0 1) surface from -1.293 kJ/mol to -0.824 kJ/mol, decreased the number density of H2O molecule towards malachite (-2 0 1) surface from 0.18 & Aring;(-3) to 0.12 & Aring;(-3), induced hydrophobicity of malachite surface.

This study conducted a theoretical analysis on the hydrodynamic factors of surface cleaning and then carried out detection on the surface physicochemical properties of coarse/fine coal particles after surface cleaning. Results show that the desorption degree of fine slimes does not increase monotonically with the impeller speed. Within the range of conventional high-intensity conditioning rotation speeds, a medium impeller speed of 1600-1900 rpm was the appropriate speed for surface cleaning. The cleaning effect depended on the impeller speed rather than the cleaning time. Surface cleaning increased the contact angle, single-bubble loading capacity, and induction time by 18.67%, 65.96%, and 28.99%, respectively. XPS analysis results indicated that when the cleaning impeller speed was 1600 rpm, the content of C-C/C-H on the surface of +75 mu m coal samples increased by 4.10%, while the content of hydrophilic groups such as C-O-C/C-OH decreased by 15.23%. SEM-EDS analysis results showed that, after surface cleaning, the content of C element on the surface of coarse coal and fine coal increased by 34.48% and 25.51%, respectively; the contents of O, Al, and Si elements in coarse coal decreased by 57.16%, 88.79%, and 83.85%, respectively, while those in fine coal decreased by 32.22%, 62.79%, and 55.42%, respectively.

The efficient extraction and separation of valuable metal elements from coal gasification fine slag (CGFS) are crucial for the comprehensive high-value utilization of its constituents. This study focused on the carbon-rich components of CGFS (CGFS-H) and systematically investigates the selective leaching behavior of Fe3+, Al3+ and Ca2+ using three organic acid extractants, i.e., citric acid, tartaric acid, and tetrasodium iminodisuccinate. Additionally, the stepwise leaching of iron, aluminum and calcium from CGFS-H is explored. The selective dissolution mechanisms of these metals by different organic acids are elucidated through X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM) analyses. The results indicate that tetrasodium iminodisuccinate exhibits the highest leaching selectivity for Fe3+, while tartaric acid demonstrateds a comparable affinity for both Fe3+ and Al3+. In contrast citric acid shows superior selectivity toward Ca2+. The leaching yield of Fe3+, Al3+ and Ca2+ after sequential leaching with the three organic acids were 79.8%, 65.08% and 78.6%, respectively. These findings confirm that effective and selective separation of Fe3+, Al3+ and Ca2+ from CGFS-H can be achieved via optimized organic acid-based leaching strategies. This advancement provides a critical foundation for developing Ca/Fe/Al hydrotalcite materials using CGFS-H as a sustainable feedstock, thereby facilitating the transformation of waste residue into high-value functional materials and promoting resource-efficient utilization of coal gasification fine slag.

Mercury (Hg(II)) contamination in wastewater poses severe environmental risks due to its toxicity and mobility. In this study, a FeS-modified fly ash-derived Mg–Al layered double hydroxide (FeS–FA–LDH) was developed for efficient Hg(II) removal by integrating fly ash valorization with sulfur functionalization. The synthesized FeS–FA–LDH achieved over 99% Hg(II) removal under optimized conditions (pH 7, 0.5g/L dosage) with an experimental Hg uptake of 125.07mg/g. In contrast, pristine FA–LDH showed a much lower experimental Hg uptake of 6.24mg/g, demonstrating the substantial enhancement resulting from FeS functionalization. Adsorption kinetics followed the pseudo-second-order model, and equilibrium data were best described by the Sigmoidal isotherm model. The Langmuir model yielded a Langmuir-derived maximum adsorption capacity of 322mg/g at 298K. Hg(II) removal is associated with strong interactions between Hg(II) and sulfur-containing sites of the FeS phase, leading to Hg–S-mediated immobilization. The Mg–Al LDH matrix provides the structural framework for FeS functionalization, while FeS supplies the sulfur-containing sites involved in Hg(II) immobilization. The combination of sulfur functionalization and a fly ash-derived LDH matrix provides an effective strategy for Hg(II) immobilization while enabling the valorization of fly ash.

Innovation in collector is pivotal to overcoming bottlenecks in the flotation separation of coal gasification fine slag (CGFS). The combination of oil-based reagents with surfactants represents an effective approach to enhancing flotation performance. However, the mechanism by which nonionic surfactants enhance the effectiveness of oil-based collectors in CGFS flotation remains unclear. This study employed n-dodecane (n-D) as the base oil agent, which was blended with three nonionic surfactants of ODEA, Span 80, and TX-100 to prepare composite collectors. Their effects on CGFS flotation were investigated through flotation experiments and kinetic modelling, whilst their microscopic mechanisms were elucidated from an adsorption perspective via characterization tests (zeta potential, FTIR, XPS) and molecular dynamics simulations. The results indicate that the composite collectors exhibit superior flotation performance compared to n-D alone. The combustible recovery rates and flotation rates are ranked as n-D/TX-100 > n-D/Span 80 > n-D/ODEA > n-D. The composite collector reduces the electronegativity of residual carbon surfaces in CGFS, masks hydrophilic groups and enhances bubble adhesion. n-D covers the hydrophobic regions of the residual carbon, whilst surfactants cover the hydrophilic regions; their synergistic adsorption enhances the collector's diffusion coefficient and interfacial adsorption energy, restricting the wetting and spreading of water molecules. This facilitates hydrophobic modification of the residual carbon surface and improves its floatability. This research can provide theoretical support for refining the CGFS flotation theory and developing highly efficient collectors.

The strong surface hydrophilicity of azurite leads to its low recovery, and the poor flotation separation between azurite and gangue minerals further reduces the utilization efficiency of copper. This study presents a novel selective collector 1-(3-(trifluoromethyl)phenyl)thiourea (3-TPT) for the efficient recovery of azurite from K-feldspar. Results from flotation tests and contact angle measurements indicate that with 150 mg/L 3-TPT, the contact angle of azurite surface raised to 79.4°, the recovery reaches 94.16 %, while K-feldspar remains hydrophilic, with a recovery of only 11.29 %. The selective adsorption mechanism of 3-TPT on azurite surface was revealed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) analyses. XPS and FTIR analyses indicate that after the interaction of 3-TPT with the azurite surface, the CN stretching in 3-TPT exhibits a notable shift, and changes in the chemical states of Cu and S are observed during adsorption, confirming that 3-TPT chemically adsorbs onto azurite via the formation of NCuSC rings, whereas its adsorption on K-feldspar is negligible. SEM-EDS results further confirm the selective interaction of 3-TPT on azurite surface, as evidenced by changes in surface morphology and elemental analysis. Characteristic elements S, N, and F from 3-TPT were clearly detected on the azurite surface in EDS mapping. This research highlights the potential of 3-TPT in copper concentration, not only improving the recovery efficiency of copper resources but also contributing to the advancement of more environmentally friendly direct flotation practices for copper oxide minerals.

Coal gasification generates fine slag with high residual carbon, but its porous structure hinders efficient separation. This study investigates carbon–ash separation of gasification fine slag using a spiral chute. Particle size and pore structure jointly determine separation outcomes. Effective separation was achieved for +0.125 mm and 0.125–0.045 mm fractions, which exhibit developed porous carbon skeletons, yielding concentrate ash of 20.22% and 39.50%, respectively. Conversely, the −0.045 mm fraction (41.16% of feed) consists predominantly of mineral microspheres with poorly developed pores, leading to high feed ash (80.73%) and poor separation (concentrate ash 76.35%). Pore structure governs separation by reducing effective density through water absorption: high-porosity particles behave as light products and report to concentrate. Optimal conditions (10% concentration, 1.96 m3/h) achieved 64.67% carbon recovery and 52.92% concentrate ash. A Bagnold-based model reveals that radial particle position is co-determined by effective density and particle size, with fine particle entrainment limiting separation precision.

Low-rank coals exhibit strong surface hydrophilicity, causing their poor response to traditional hydrocarbon collectors in flotation. Screening and developing effective collectors present a promising solution to improve low-rank coal flotation. This study proposes a novel approach for evaluating the performance of cationic collectors in long-flame coal flotation by integrating Density Functional Theory and Molecular Dynamics simulations. The results indicate that while the three amine collectors possess similar polar group charges, dodecylamine and HDMEA (CH3(CH2)11NH(CH3)2CH2OH) demonstrate a higher number of hydrogen bond donors/acceptors. This characteristic leads to significantly stronger adsorption energies for dodecylamine (-270.35 kcal/mol) and HDMEA (-264.13 kcal/mol) compared to tridodecylamine (-68.62 kcal/mol) on the coal surface, enhancing their collecting power. In contrast, tridodecylamine features a substantially larger polar group size (302.48 & Aring;3 in volume) than dodecylamine (23.29 & Aring;3 in volume), contributing to obtain a superior selectivity index. Consequently, tridodecylamine is predicted to achieve a better balance between collecting power and selectivity in coal flotation. Experimental flotation results corroborate the theoretical analysis, validating the reliability of the selectivity index as a predictive metric for cationic collector performance. This work provides valuable insights for the molecular design of future cationic collectors for low-rank coal flotation.

Coal slime settling is a crucial aspect of coal slime water (CSW) treatment, which is related to the purification and recovery of resources in the coal industry. Current research on coal slime settling is primarily focused on the properties of reagents and coal slime itself, and there are few investigations on the influence of water property variations on coal slime settling. This study tentatively explored the effects of plasma-activated water (PAW) on coal slime settling through settling experiments and turbidity detections. Potential mechanisms influencing settling were analyzed using laser particle size analysis, microscopic morphology observations, fractal dimension calculations, zeta potential measurements, and contact angle assessments. Experimental results indicated that PAW increases the initial settling velocity, reduces the supernatant turbidity, shortens the settling end time, and decreases the final thickening layer thickness. Mechanism analysis indicates that PAW reduces electrostatic repulsion between coal particles and decreases their hydrophobicity, significantly increasing the sizes of coal slime flocs while slightly reducing their density, thereby promoting settling efficiency. This study introduces a novel approach for coal slime settling, offering valuable insights into the efficient settling of coal slime facilitated by PAW, and holding significant scientific importance.

In this study, to examine the applicability of prediction models when dealing with long-term and large-scale industrial on-site data, a total of 26,225 pieces of industrial flotation data were collected continuously for 45 days from an industrial site. The prediction of the Random Forest (RF), eXtreme Gradient Boosting (XGBoost), Deep Neural Network (DNN), Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), as well as the hybrid models DNN-LSTM and LSTM-DNN for flotation reagent dosage were compared. The results show that when predicting with a single model, the MRE of RF for the dosage of collector and frother are 5.94% and 8.11%, respectively, which achieves the best performance. However, the prediction performance of the hybrid model outperforms that of the single DNN, LSTM, or RF models. The MRE of LSTM-DNN model for the collector and frother reached up to 4.39% and 6.26%, respectively. This indicates that neural network models are applicable for training with large-scale data in actual flotation industries.

Waste fried oil (WFO) and coal gasification fine slag (CGFS) are both environmentally hazardous wastes, and the flotation separation of resources from CGFS is over-reliant on non-renewable petrochemicals as collectors, it is significant to utilize WFO to prepare renewable collectors for CGFS separation. In this study, six surfactants were selected to be compounded with WFO to prepare renewable collectors, and the flotation effect of the compounded collectors on CGFS and the surfactant-enhanced mechanism for WFO flotation effect were examined through flotation experiments, flotation kinetics experiments, laser particle size analysis, FTIR analysis, XPS analysis, and induction time tests. The results show that WFO alone needs to be used in a large dosage (>30 kg/t) in order to show better flotation performance than diesel, while the flotation performance is greatly improved after compounding with surfactants, among which the best effect is achieved with Span80, and the dosage cut-off point of the compounded collector for flotation better than diesel is reduced to 12.5 kg/t. The surfactant can make the dispersed droplet size of WFO in water decrease from D-50= 120 mu m to 5.63 mu m. Meanwhile, the surfactant-assisted WFO can be adsorbed on the residual carbon surface of CGFS through hydrophobic and hydrogen-bonding forces, which can mask the hydrophilic region of the carbon surface and enhance its hydrophobicity. Surfactant-assisted WFO can further shorten the adhesion induction time between CGFS particles and air bubbles, thus facilitating the recovery of more residual carbon in a shorter period of time. The findings can provide theoretical basis and technical support for the resourceful disposal of WFO and CGFS synergistically.

The residual carbon contained in coal gasification fine slag (CGFS-RC) is a valuable resource with great potential for application, and the elucidation of the macromolecular structural model of CGFS-RC is an important basis for its recovery and utilization. In this paper, CGFS-RC was comprehensively characterized by proximate, ultimate, FTIR, XRD, XPS, and HRTEM analyses, and the macromolecular geometric model of CGFS-RC was constructed and optimized using Materials Studio software. The results show that carbon atoms in CGFS-RC mainly exist in the form of aromatic carbons with a high percentage of 90.7 %, and the ring number of condensed aromatic rings is mainly 3-5. The aliphatic carbon side chain structure on the benzene ring is mainly dominated by cycloalkanes. Among the heteroatoms, oxygen atoms are mainly present in the form of ether-oxygen bonds, (phenolic) hydroxyl groups, carbonyl groups and carboxyl groups, while nitrogen atoms are mainly present in the form of pyrroles. The molecular formula of CGFS-RC can be expressed as C165H41O13N, and the density of its geometrical configuration was calculated to be 1.65 g/cm3. The XRD and FTIR simulation confirmed the reasonableness of the constructed model, and the electrostatic potential simulation revealed the hydrophilic properties of CGFS-RC at the molecular level. This study opened up the molecular structure analysis and modeling process of CGFS-RC, which can provide fundamental basis for the reagent design in the flotation recovery of CGFS-RC as well as the resource utilization of CGFS-RC. (c) 2025 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Coal gasification fine slag (CGFS) has caused serious ecological consequences and urgently need to be utilized as resources. Preparation of porous carbon materials using carbon-rich fractions (CRF) separated from CGFS is an important way to achieve CGFS efficient utilization. According to the physical characteristics of CRF, a reactionseparation-preparation strategy was proposed that the carbon activation and silicon separation processes were coupled by the action of mixed alkali to prepare porous carbon materials as CO2 adsorbents, in which the separated silicon-rich solution also can be used as precursor for porous silicon-based materials. The activation experiments revealed that the optimum conditions for carbon activation and silicon separation simultaneously by mixed alkali were KOH: NaOH = 0:4, alkali: carbon = 4:1, and activation temperature of 620 degrees C, under which the CO2 adsorption capacity and silicon extraction yield were 1.341 mmol/g and 66.03 % respectively. The effect mechanism of mixed alkalis on the reaction-separation-preparation process was further analyzed using BET, SEM, TEM, Raman spectra, FT-IR, XPS, and XRD. The results showed that the etching action of the mixed alkali expanded the pore structure, added surface oxygen-containing functional groups and formed graphitization defect sites, which all favored CO2 adsorption. Meanwhile, the mixed alkali destroyed the stable Si-O-Si and Si-OAl bonds in the CRF, and the aluminosilicate minerals were depolymerized and transformed into new amorphous silicate phases with higher reactivity, which is conducive to the separation of silicon. This study can provide guidance for mitigating the environmental pollution of CGFS and its resource utilization in the environmental field.

With the development of the coal chemical industry, the emission of coal gasification slag (CGS) has grown rapidly, raising widespread concerns about environmental pollution and resource waste. The composition and structural characteristics of CGS, such as high contents of carbon, silicon, and aluminum and well-developed pores, enable the preparation of CGS-based adsorbent materials for wastewater treatment and gas purification, thus promoting high-value resource utilization of CGS and achieving the goal of "treating waste with waste." On the basis of the compositional and structural characteristics of CGS being summarized in this review, the preparation methods of CGS-based adsorbent materials, such as activated carbon, zeolite, mesoporous silica, and carbon-silica composites, are systematically outlined as well as their preparation mechanisms are deeply elucidated. Then, the current application status and adsorption mechanisms of various types of CGS-based adsorbent materials in the fields of wastewater treatment and gas purification, such as heavy-metal removal, nitrate removal, ammonia-nitrogen removal, dye removal, CO2 absorption, and pollutant adsorption-catalytic degradation, are fully discussed. Finally, bottlenecks and key research directions in the preparation of highvalue-added adsorbent materials from CGS are summarized and prospected. This review is of significant relevance in promoting the product development and industrial application of CGS in the field of adsorption.

Washery reject is a by-product discharged during coal preparation, in which there are still certain amount of valuable combustibles. The recovery of clean coal from washery rejects is of great significance for protecting China's scarce coking coal resources. The main purpose of this work was to design a deep process that can maximize the recovery of clean coal from a coking coal washery rejects with about 50% ash and test the technical feasibility of the process. Based on fundamental analyses, the high ash fractions of +0.2 mm and +1.80 kg/cm(3)were firstly removed from the raw coal sample via hydrocyclone and spiral separator. Then, the remained parts having an ash of 27.57% were ground, pre-conditioned, and separated by flotation. The results showed that, under the optimum process parameters, a maximum yield of 24.47% clean coal with 12.23% ash can be recovered from this washery rejects. The ash content of the washery rejects increased from 50.10% to 62.37% after this treatment. This study indicated that it was technically feasible to achieve deep recovery of clean coal from washery rejects, which was of significance for the treatment of coking coal tailings.

Low-rank coals due to their strong surface hydrophilicity often response poorly to the flotation process with the traditional hydrocarbon oil used as collectors. In this study, a novel collector, i.e. oxidized diesel, containing oxygenated groups, was prepared via an instantaneous gasification-oxidation-condensation device for the expected enhancement of low-rank coal flotation. The FTIR and XPS analyses showed that the coal sample had rich oxygenated groups on its surface, causing extremely low floatability. The combustible matter recovery in flotation was only 67.25% even though consuming 100 kg/t of common diesel. In contrast, a combustible matter recovery of 90.52% could be obtained at a dosage of 6 kg/t of oxidized diesel, showing excellent flotation performance. Additionally, an optimization of the technological parameters, including the novel collector dosage, impeller speed, pulp concentration and aeration rate, was conducted regarding the flotation of coal sample via the software Design - Expert 12, and a function model of the combustible matter recovery was established. Finally, with the recovery model solved, an optimization scheme obtaining a combustible matter recovery of 86.64% was determined as collector dosage of 4.18 kg/t, the flotation pulp concentration of 40.00 g/L, the impeller speed of 1719 rpm, and the aeration rate of 0.02 m3/h.

Aiming at the defects such as poor dispersion and high consumption of conventional diesel collector in the flotation process of aluminum electrolysis anode carbon slag (CS), a microemulsion diesel collector was prepared, and its performance and mechanism in CS flotation were investigated by means of flotation experiments as well as modern analysis methods (surface tension, laser particle size, zeta potential, FTIR, etc.). A complex of sorbitan monooleate (Span 80) and cetyltrimethylammonium bromide (CTAB) was used as the primary surfactant, and the optimal formulation of the microemulsion collector was HLB of 8, co-surfactant of n-butanol, Km of 1.7, and oil-surfactant-water mass ratio of 27.80:27.8:44.40, and the droplet size of the obtained microemulsion collector was 62.22 nm. The flotation results showed that a carbon recovery of 74.48 % was obtained at a microemulsion collector dosage of 400 g/t, which resulted in a collector saving of 66.67 % with similar flotation indexes. The flotation process of microemulsion diesel for CS is in accordance with the classical first-level kinetic model, and its flotation rate is faster than that of conventional diesel. Analysis test results showed that microemulsification resulted in smaller droplet size and better dispersion of diesel collector in water, which enhanced its adhesion to carbon particles even at low reagent dosage. At the same time, the microemulsion diesel reduces the electronegativity of the CS particles and enhances the coverage of oxygenated functional groups on the carbon surface, thus enhancing the hydrophobicity of the carbon particles and improving its flotation recovery performance. This research can provide new theoretical basis and technical support for efficient waste disposal and resource recovery for CS.

Coal gasification fine slag (CGFS) is a large solid waste in the field of coal chemical industry, and the separation of its carbon and ash is a prerequisite for the large-scale utilization of CGFS. At present, the flotation separation process of CGFS faces the prominent bottleneck of high consumption of traditional non-polar hydrocarbon oil collectors and poor flotation effect. To address this challenge, three fatty acids, oleic acid (OA), n-decanoic acid (DA), and naphthenic acid (NA), were used in this study to compound with the nonpolar hydrocarbon oil dodecane, respectively, as novel collectors for CGFS flotation. The effect and action mechanism of the composite collectors on CGFS flotation were investigated through flotation experiments as well as surface/interfacial tension, laser particle size, heat of wetting, FTIR, XPS, and induction time tests. The results show that the composite collectors can enhance the flotation effect of CGFS while reducing the chemical consumption. The addition of polar fatty acids can effectively reduce the interfacial tension of the collector-water system and thus increase the dispersion of the collector in water. Meanwhile, the addition of fatty acids makes the composite collector contain both polar and nonpolar groups. The polar groups form hydrogen bonds with the oxygen-containing groups on the residual carbon surface to mask the hydrophilic region, and the nonpolar groups are exposed to the slurry to enhance the hydrophobicity of the residual carbon surface, which makes the residual carbon adhere to the air bubbles more easily and thus facilitates its flotation recovery from CGFS. This study has important theoretical guidance for the efficient separation and resource recovery of CGFS.