Selective Phase Transformation Behavior of Titanium-bearing Electric Furnace Molten Slag during the Molten NaOH Treatment Process

Abstract

In this paper, selective phase transformation for titanium-bearing phase (Ti-bearing phase) and impurity phase in titanium-bearing electric arc furnace molten slag (Ti-bearing EAF slag) was effectively realized during the molten NaOH treatment process. The phase transformation mechanism based on thermodynamic calculation was investigated in detail by X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectrum. It is indicated that the Ti-bearing phases in Ti-bearing EAF slag such as anosovite solid solution and Mg2TiO4 can be easily converted to Na2TiO3 with NaCl-type crystal structure, whilst the main impurity phase such as MgAl2O4 was apt to be decomposed by molten NaOH to form NaAlO2 and MgO. In addition, with increasing of roasting temperature and time, as well as decreasing of Ti-bearing EAF slag/ NaOH mass ratio (Rslag/NaOH), the formed Na2TiO3 could be partly changed to NaMO2 (M=Mg, Ti, Fe) with α-NaFeO2-type crystal structure, due to the coexisting metal ions like Mg 2+ and Fe 3+ in the slag be doped into or even substituted the Ti atoms of Na2TiO3 to form NaMO2 (M=Ti, Fe, Mg).

Natural Rubber Latex Foam Reinforced with Micro- and Nanofibrillated Cellulose via Dunlop Method

“…Crystalline NaOH have diffraction patterns at another 2θ value [ 22 ] than this observed result. The most intensive patterns for NaOH have to be at about 38 and then 32° [ 26 ]. In this case the observed patterns could be most probably connected with Na-cellulose formation [ 24 ].…”

Hydrothermal synthesis of mixtures of NaA zeolite and sodalite from Ti-bearing electric arc furnace slag

“…According to our previous research, 22 Si and Al could be converted to Na 2 SiO 3 and NaAlO 2 during the molten NaOH treatment, respectively. Then, they were separated from other elements by water leaching and dissolved in water to form the precursor, which was the raw material to prepare zeolite.…”

“…Then the alkaline solution containing sodium aluminate and sodium silicate were obtained in the water leaching process, which was an ideal precursor to prepare NaA zeolite. 22 However, until now, none of the work has been reported yet.…”

Effects of CaO/SiO₂ on Viscous Behaviors and Structure of CaO-SiO₂-11.00wt%MgO-11.00wt%Al₂O₃-43.00wt%TiO₂ Slag Systems

“…By the appropriate hydrometallurgical process, the titanium-bearing components in this type slag can be efficiently extracted. 8,9) Importantly, the practical experience indicates that the slag system plays an important role in the smelting process. The viscous behaviors (i.e., viscosity, break point temperature, activation energy for viscous flow) of slag can not only affect the productivity and operation stability, but also…”