Abstract:

By adjusting the pH of the H2SO4 leaching liquor of fly ash, Ti4+ and Fe3+ were extract-separated with trioctylphosphineoxide(TOPO)kerosene and di(2-ethylhexyl) phosphoric acid（P204）-kerosene, respectively. Effects of the extractants, the concentration of the cations, pH of the aqueous solution, extracting temperature, and extracting time on the extracting efficiency were investigated. Effect of the recycle conditions of the loaded extractants on the recovery yield and the purity of recovered products were discussed as well. The phase of the precursor and its calcined products were characterized by X-ray diffraction(XRD). The purity of the TiO2 and Fe2O3 were determined by X-ray fluorescence（XRF）. The analysis results show that the extracting-titanium efficiency and the extracting-iron efficiency were as high as 97%. The extraction yields of ferric oxide and titanium dioxide are 96% and greater than 92%, respectively. The purities of TiO2 and Fe2O3 are 98% and 97%, respectively, which can be used as a white pigment or iron oxide red pigment in the production of paints, respectively.

Key words: fly ash, Ti4+, trioctylphosphineoxide, di(2-ethylhexyl)phosphoric acid, Iron Removal