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The flotation separation and mechanism of dextrin on chalcopyrite and arsenopyrite surface were investigated by micro-flotation tests, zeta potential measurements, infrared spectroscopy, Contact angle measurement and surface adsorption experiments. The micro-flotation test shows that dextrin has obvious inhibitory effect on arsenopyrite flotation, but has no inhibitory effect on chalcopyrite flotation. After treating the surface of arsenopyrite with dextrin, the infrared spectra showed that new characteristic peaks were found, indicating that the chemical adsorption and significant interaction between dextrin and arsenopyrite particles occurred. Zeta potential measurements, Contact angle measurement and surface adsorption experiments show that the selective adsorption of dextrin rendered a large number of hydrophilic groups on the surface of arsenopyrite, but has little effect on chalcopyrite. In addition, the macromolecular chain structure of dextrin may hinder the attachment of collector molecules to arsenopyrite. The combined effect of these two aspects makes the arsenopyrite treated with dextrin lose its hydrophobicity and realizes the separation of chalcopyrite and arsenopyrite.

Diatomite was modified by chitosan to prepare modified diatomite, and the modified diatomite in an optimized ratio was utilized in coal bio-flocculation. The interaction behavior and flocculation mechanism of modified diatomite on coal slurry water were investigated by single factor experiments, infrared spectroscopy, Brunauer-Emmett-Teller (BET) measurements, and zeta potential measurements. The single factor experiments showed that when the amount of microbial flocculant added was 1.5 ml, the temperature of coal slurry water was 39 °C, the pH was 5, and the amount of modified diatomite was 0.2 g, after 30 min of sedimentation, the flocculation transmittance of the coal slurry water reached 84.3%. The infrared spectra showed that the -NH2 and -OH of the chitosan molecule had a polar interaction with the Si-OH bond in diatomite. The BET measurements showed that the specific surface area of diatomite was not a decisive factor affecting the flocculation effect. Zeta potential measurements indicated that the amino protonation of chitosan increased the isoelectric point (IEP) of modified diatomite. These results showed that modified diatomite has a good effect on coal bio-flocculation.

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