Abstract
In this study, enrichment methods for coal fly ash (CFA) from Omsk thermal power station No. 4 (TPS-4) were investigated. The magnetite and unburned carbon concentrates were obtained by magnetic separation and flotation methods. The wet magnetic separation used in the study increased the magnetite content in the magnetic fraction from 10.48 to 12.72 wt % compared to dry magnetic separation. The XRD analysis showed that the magnetic fraction primarily consists of magnetite, mullite, and quartz. The SEM analysis demonstrated that magnetite is located primarily on the surface of alumosilicate spheres and has three types of shape: dendritic structures, hexagonal bulk agglomerates, and star-like structures. For the flotation tests, a low-price diesel was used as the collector. It was found that, if CFA particles of 40–71 µm are used, ~99% of unburned carbon can be recovered. It was also found by SEM that, if CFA particles of 71–100 µm are used, alumosilicates on a carbon surface prevent complete interaction of diesel with carbon particles and decrease thereby carbon recovery to 83%.
Highlights
~230 thousand tons of coal fly ash (CFA) are generated at thermal power station No 4(TPS-4) in Omsk after burning coal from the Ekibastuz deposit, Republic of Kazakhstan [1]
The purpose of the present paper is to investigate the maximum separation of magnetite and unburned carbon from the alumosilicate fraction of the Omsk CFA
The X-ray diffraction (XRD) analysis of raw CFA (Figure 1) and non-magnetic fraction were carried out using a Dron-3M diffractometer
Summary
~230 thousand tons of coal fly ash (CFA) are generated at thermal power station No 4(TPS-4) in Omsk after burning coal from the Ekibastuz deposit, Republic of Kazakhstan [1]. CFA is not being utilized, it is stored on disposal sites near the Irtysh River. This river may be polluted in summer time after dust storms when disposal sites become dry. The Omsk CFA mainly contains 20–35 wt % alumina, 50–65 wt % silica, 5–15 wt % magnetite, and up to 6 wt % unburned carbon [1,2]. Previous research was aimed mainly at studying methods for producing alumina [3,4,5,6], ceramics [7,8,9,10], coagulants [11,12], and the extraction of the rare-earth elements [13,14,15,16,17]. Our previous research was about the leaching of alumosilicates with hydrochloric acid
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