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The aqueous chemistry of micron-sized lignite particles has essential influences on the dispersion stability of water-lignite slurry. In this work, the adsorption behaviors of dissolved humics on lignite surface in lignite–water slurry were studied through batch adsorption experiments. The influences of adsorbed humics on the surface properties, particle size distribution and dispersion stability of lignite particles in water-lignite slurry were examined by advanced analysis techniques, EDLVO theory and settlement tests. The adsorption results indicate that the adsorption capacity of humics on lignite increases from 4.11 mg·g−1 to 8.25 mg·g−1 with the humics concentration increasing from 100 mg·L−1 to 200 mg·L−1. The adsorption process can be well described by the pseudo-second order kinetic model. The adsorbed humics significantly improves the hydrophilicity and electronegativity of lignite surface and reduces the apparent particle size of lignite. The EDLVO calculation and settlement tests reveal that the total interaction energy of the humics-adsorbed lignite particles at 18 nm of separation distance is enhanced from 0.85 × 10−17 J to 1.45 × 10−17 J with the initial humics concentration increasing from 100 mg·L−1 to 200 mg·L−1. The dispersion stability of micron-sized lignite particles is improved with humics adsorption on lignite surface.

In order to remove aluminum ions in bauxite processing wastewater, two natural clay minerals (bentonite and kaolin) were used as adsorbents. The adsorption behaviors including kinetics and isotherms were studied at much broader pH range, higher temperature, and higher Al(III) concentration by batch experiments. The adsorption mechanisms were investigated by optical microscope, zeta potential testing, and XRD analysis. The results show that Al(III) adsorption is strongly pH dependent and increases clearly with increasing pH. The pseudo-second-order kinetic model can best describe the adsorption process, and the intra-particle diffusion was not the sole rate-controlling step. The Langmuir–Freundlich model can fit best the adsorption equilibrium data, and the maximum capacities of Al(III) adsorbed on bentonite and kaolin reach to 8.52 mg g–1 and 0.58 mg g–1, respectively, at 35°C. Thermodynamic studies display that the adsorption of Al(III) onto clay minerals is non-spontaneous. The adsorption of Al(...

The flotation desulfurization is generally used for the removal of sulfur impurities in the high sulfur bauxite. 1-butyl-2-mercaptobenzimidazole (DMBI) was synthesized and used as collector in the laboratory. The interactions between DMBI and pyrite with different adsorption time, solution pH, solution temperature and DMBI concentration were investigated in this work. Results show that the equilibrium adsorption time is 20 min, and the adsorption capacity decreases with increasing pH as well as temperature. With the increasing concentration, adsorption value increases and achieves the saturated adsorption. The adsorption of DMBI on pyrite is more consistent with Langmuir isothermal adsorption equation from 298.15 to 318.15 K. However, the adsorption is more fitted by the Freundlich isothermal adsorption equation at 288.15 K. Thermodynamic studies display that the adsorption of DMBI and pyrite is non-spontaneous and exothermic.

Physicochemical Problems of Mineral Processing; ISSN 2084-4735