No abstract

A series of Na5La(WO4)4:M3+ (M = Eu, Sm, Bi) phosphors have been synthesized successfully by the solid-state reactions. The corresponding crystal structure and lattice parameters were refined by the Rietveld method, and the impact of doped metal ions upon the structure were also studied. The photoluminescent properties were investigated at room temperature. All the samples were observed a strong red emission under 395nm or 465 nm excitation, and the CIE chromaticity coordinates (x = 0.67, y = 0.33) was found to be close to the National Television Standard Committee (NTSC) standard red, implying high color purity. This kind of tungstate phosphor is a promising candidate as the red phosphor for white light-emitting diodes (WLED).

Ca-α-sialons with low oxygen content were fabricated at 1800°C by hot pressing. The phase and microstructure were characterized by XRD and SEM. The calculated lattice parameter reveals that 20~30% Ca2+ ions still exist in the grain boundary phase of Ca-α′. A large amount of Ca-containing liquid phase efficiently promotes the anisotropic growth of α′ grains in Ca-rich composition. Reinforced only by elongated α′ grains, the fracture toughness of Ca-α′ can reach 4.96 MPa•m1/2.

Mg(OH) 2 -based emulsion has been successfully prepared from the alkaline iron slag in the laboratory for the first time, and the wet Flue Gas Desulfurization (FGD) process with Mg(OH) 2 -based absorbents was researched through a simulated experimental set-up. The desulfurization efficiency was 89.0%~90.8% under the conditions of sorbent concentration 21.2~63.6 g/L and the retention time (T s ) 30s. Effects of gas flowrate (Q), sorbent concentrate of Mg(OH) 2 -based emulsion and the retention time (T s ) on the desulfurization efficiency were also investigated in this paper. Research results indicated that Mg(OH) 2 -based emulsion is a new absorbents for wet FGD technology with investment-saving, low operation cost and high desulfurization efficiency.