Effect of titanium chelating compound on hydration resistance of CaO material

Abstract

The hydration resistance of CaO materials prepared by Ca(OH)2 calcination with titanium chelating compounds is investigated in this paper. The crystalline phases and microstructure characteristics of sintered specimens were studied by X‐ray diffraction (XRD), define FTIR spectroscopy, scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The results showed that the hydration resistance of CaO samples was improved significantly, especially for samples with 9 wt% Ti chelating compound. The specimens with Ti chelating compound showed an increase in bulk density and a decrease in apparent porosity after heating when compared to the specimens without additive. The grain surface of CaO grain and the gaps between the CaO grain boundaries were covered with calcium phosphate glass phase, calcium phosphate showed two different shapes: irregular shape and rod shape. The formation and distribution of these two forms were the key factors that affecting the hydration resistance of CaO samples.

Fabrication of CaAl12O19–CaTiO3 composites and their potential usage for TiAl alloy smelting

“…Electromagnetic stirring can provide good degassing and alloy homogenization, which improves mechanization and automation. 7 However, compared with other commonly used alloys, the fabrication of TiAl alloys requires higher processing temperatures (above 1600 • C), indicating a higher chemical activity of the molten alloy. 8,9 In this case, the alloy melt reacts heavily with the refractory crucible, resulting in impurities, inclusions, and casting defects in the produced alloy.…”

“…Compared with other common electric furnaces, it has the advantages of a fast heating rate, high production efficiency, and reduced oxidation loss. Electromagnetic stirring can provide good degassing and alloy homogenization, which improves mechanization and automation 7 . However, compared with other commonly used alloys, the fabrication of TiAl alloys requires higher processing temperatures (above 1600°C), indicating a higher chemical activity of the molten alloy 8,9 .…”

Improved hydration resistance of CaO granules via sol‐processed metal oxide protective layers

“…Therefore, lots of works have been done to fabricate densified lime‐based refractories by proper treatment on the raw material such as reducing the particle size, adding appropriate additives, granulation, 7,8 and increasing the firing temperature 9 . Some sintering aids, such as Al 2 O 3 , Fe 2 O 3 , and V 2 O 5 can promote the densification of CaO materials by liquid sintering 10‐14 . Another strategy is to use additives like lanthanides, ZrO 2 and TiO 2 , to form a high melting point phase by reacting with CaO, which promotes the solid‐state sintering 15‐18 .…”