Reverse Flotation of Taixi Oxidized Coal

Abstract

X-ray photoelectron spectroscopy (XPS) was used to indicate the chemical properties of Taixi oxidized coal. The results of XPS analysis showed that Taixi oxidized coal contained many oxygen functional groups. The results of our previous studies (conventional flotation tests using diesel as collector) indicated that Taixi oxidized coal was difficult to float. A concentrate yield of 24.89% could be only obtained even at a very large diesel dosage (25 kg/t coal). Therefore, reverse flotation was introduced to upgrade Taixi oxidized coal in this investigation. Dextrin and hexadecyl trimethyl ammonium bromide (HTAB) were used as depressant and collector, respectively. The effects of dextrin and HTAB dosages on reverse flotation behavior of different size fractions (−0.5 + 0.25 mm, −0.25 + 0.125 mm, −0.125 + 0.074 mm and −0.074 mm) were also discussed. Both dextrin and HTAB dosages had a significant effect on reverse flotation behavior of coarse coals (−0.5 + 0.25 mm and −0.25 + 0.125 mm) but had a little effect on reverse flotation behavior of fine coals (−0.125 + 0.074 mm and −0.074 mm). Throughout this study, reverse flotation was found to be especially suitable for the upgrading of Taixi oxidized coal.

Ionic-liquid collectors for rare-earth minerals flotation⿿Case of tetrabutylammonium bis(2-ethylhexyl)-phosphate for monazite and bastnäsite recovery

“…According to Table 1, this group was the most abundant carbon group in the ionic liquid thus causally linking it with the hydrophobicity inherited by the bastnäsite surface. This is to mirror with a tendency of the hydrophilic C2 and C3 [75] functional groups (Table 3) to decline after IL treatment. Moreover, the slightly negative correlation between the fraction of surface hydrophobic groups and pH (Table 3) was in agreement with the micro-flotation recoveries and the promoted hydrophobicity of the IL-treated bastnäsite at pH 7.…”

“…Therefore, the following discussion refers solely to the surface analysis of bastnäsite from which the behavior of monazite can be extrapolated in terms of IL interactions. For bastnäsite model mineral, the C1 contribution to C 1s core level spectrum (Table 3) was assigned to the C C/C H hydrophobic groups [75] whose contribution was drastically inflated after IL treatment. According to Table 1, this group was the most abundant carbon group in the ionic liquid thus causally linking it with the hydrophobicity inherited by the bastnäsite surface.…”

Effect of heating process on the wettability of fine coals of various ranks

“…The decomposition of alkyl side chains can increase the wettability of the anthracite coal surface whereas the decomposition of oxygen‐containing functional groups can decrease the wettability. The wettability of carbidic/graphite carbon is higher than that of alkyl side chains but lower than that of oxygen‐containing functional groups …”

A review of spontaneous combustibility of oxidized coal

“…By the method of infrared spectrum experiment, Deng [11] compared the characteristic parameters of oxidized and raw coal samples in Shaanxi Jurassic coal field, and found decreasing of moisture, increasing of oxygen content and surface area, and the number of aromatic hydrocarbon structure and fat structure were decreased for the oxidized coal. By infrared spectroscopy, Xia [12] tested the oxidation of coal surface oxygen functional groups (C-O, C=O, COOH) and the serious weathering coal surface oxidation. In addition, using quantum chemical simulation, Wang [13] found that the structure model of coal was constructed, simulating the adsorption and oxidation reaction mechanism of coal at different temperatures.…”