Grading Characteristics of Texaco Gasification Fine Slag: Quality Distinction and Selective Distribution of Trace Elements

[Image: see text] Aiming at hard-to-reuse gasification fine slag, a new process of treating gasification fine slag by classification was presented. The screening treatment was carried out based on ensuring the original particle size composition of fine slag, and it was divided into six particle size ranges as follows: +0.5, 0.3–0.5, 0.125–0.3, 0.074–0.125, 0.045–0.074, and −0.045 mm. The physical properties of different size range samples were examined by elemental analysis, X-ray diffraction, X-ray fluorescence, cold field emission scanning electron microscopy, and energy-dispersive spectrometry. The results showed that the carbon content of the median section (0.125–0.3 mm) fine slag had significant improvement compared with the other section fine slag. The carbon distribution of the +0.125 mm fine slag was concentrated, while the carbon distribution of −0.125 mm was dispersed and closely mixed with minerals. The content of trace elements Cr, Mn, Ni, V, Cd, Pb, and Mo was determined by inductively coupled plasma–mass spectrometry, and the correlation between minerals and trace elements of different particle size-graded fine slag was evaluated by Pearson correlation analysis. The results suggested that high vaporization temperature and metallic oxide forms of trace elements had a strong correlation with feldspar.