The Crystallization Behaviors of SiO2-Al2O3-CaO-MgO-TiO2 Glass-Ceramic Systems

Abstract

To evaluate the crystallization behavior of Ti-bearing blast furnace slag-based glass ceramics, SiO2-Al2O3-CaO-MgO-TiO2 systems with various TiO2 were investigated. The crystallization process and mechanical properties were analyzed. The results show that with TiO2 increasing, exothermic peak temperature (Tp) decreases, and the crystallization is promoted by the introduction of TiO2. A small amount of TiO2 (≤4%) addition can significantly promote crystallization, and when TiO2 continues to increase, the crystallization is decreased slightly. The Avrami parameter (n) of all samples is less than 4, indicating that in prepared glass-ceramics, it is hard to achieve three-dimensional crystal growth. The main crystalline phase is akermanite–gehlenite. The addition of TiO2 has no obvious effect on the type of main crystalline phase. The prepared glass-ceramic with 4% TiO2 show good mechanical properties with the hardness values of 542.67 MPa. The recommended content of TiO2 is 4% for preparing glass-ceramics.

Preparation of micro‐crystal stones from molten titanium slag by “one‐step” cooling method

“…The variation of the Gibbs free energy with temperature for reactions (5-7) is shown in Figure 8. It can be found that the standard Gibbs free-energy changes of reaction ( 5) and ( 6) is smaller than that of reaction (7), meaning that CaO prefers to react with SiO 2 rather than TiO 2 in the presence of Al 2 O 3 and MgO. Besides, it can be obtained that the increasing the SiO 2 content will promote the formation of Ca 2 MgSi 2 O 6 and inhibit the formation of CaTiO 3 .…”

“…Titanium‐bearing blast furnace slag is mainly produced by vanadium and titanium magnetite in the smelting process 4–6 . A large amount of titanium‐bearing slags is piled up randomly, which not only wastes resources, but also seriously threatens the environment 7,8 . Therefore, the disposal and reuse of titanium‐bearing slags have become a difficult issue 9,10 .…”

“…[4][5][6] A large amount of titanium-bearing slags is piled up randomly, which not only wastes resources, but also seriously threatens the environment. 7,8 Therefore, the disposal and reuse of titanium-bearing slags have become a difficult issue. 9,10 According to the amount of TiO 2 content in the slag, it can be can be divided into high-titanium contained slag (TiO 2 ≥ 20 wt%), medium-titanium contained slag (5 wt% ≤ TiO 2 ≤ 20 wt%), and low-titanium contained slag (TiO 2 ≤ 5 wt%), 11 respectively.…”

Spectroscopic and Surface Crystallization Characterizations of Yttrium-Doped Phosphate Glasses

“…Glass-ceramics have been widely reported and are generally obtained by using heat treatment techniques to control the crystallization of glass samples. The literature indicates that glass-ceramics possess better mechanical performance and higher chemical and thermal stability than the parent glasses; in particular, the presence of regular nano-crystals is helpful to improving the properties of glass-ceramics [11][12][13]. However, iron phosphate glass-ceramics containing rare earth elements have received less attention [7,10,14].…”

Effect of Cr2O3 on the crystallization, structure, and properties of Ti-bearing blast furnace slag-based glass ceramics

“…As a result, the low Ti-bearing blast furnace slag can be a good candidate for the preparation of slag-based glass ceramics [22], where a small amount of TiO 2 in the Tibearing blast furnace slag can be the nucleating agent. In our previous work [23], the effects of TiO 2 on the crystallization behavior of Ti-bearing blast furnace slag-based glass ceramics were investigated. The results suggested that it was difficult to achieve threedimensional crystal growth and two-dimensional crystallization was shown in the sample with 2 wt% TiO 2 .…”