Abstract
A novel method for preparing titanium powder by multi-stage reduction of TiO2 was proposed. Its core is the preparation of high-quality low-valent titanium oxide. In this paper, the effect mechanism of different sample preparation pressures on the preparation of low-valent titanium oxide by the primary reduction (self-propagating high-temperature synthesis mode, SHS) of the Mg-TiO2 system was studied. The results show that the generation of Mg thermal fluid is the key link of the self-sustaining chemical reaction of the Mg-TiO2 system. Titanium exists inα-Ti and TiO at the end of combustion, and constitutes a non-stoichiometric low-valent titanium oxide. The sample preparation pressure determines the proportion of pores reserved for Mg diffusion in the compacts and the contact area of the reactants, thereby determining the partitioning behavior and heat transfer effect of Mg thermal fluid during the combustion process. When the sample preparation pressure is 75 MPa (relative density is 0.66 ± 0.01), the combustion effect is optimal, and the low-valent titanium oxide with oxygen content of 15.1% can be obtained. It was subjected to deep reduction to obtain a titanium powder product with an oxygen content of 0.27%.
Highlights
Titanium is one of the most important bulk commercial metals, and the current titanium industry is based on titanium sponge produced by the high-pollution, high-energy, non-continuous Kroll process [1]
MPa (Figure 2b,c), the titanium-containing phases of the product are TiO and α-Ti, and the diffraction of α-Ti phase tends to decrease, while Mg phase disappears; when the sample preparation pressure is peak of α-Ti phase tends to decrease, while Mg phase disappears; when the sample preparation increased to 100 MPa (Figure 2d), Mg phase appears in the product; and when the sample preparation pressure is increased to 100 MPa (Figure 2d), Mg phase appears in the product; and when the sample pressure is increased to 150 MPa (Figure 2e), the diffraction peak of α-Ti phase in the product is preparation pressure is increased to 150 MPa (Figure 2e), the diffraction peak of α-Ti phase in the remarkably lowered
The titanium oxide is solid in the whole reaction process, and the liquid or gaseous Mg diffuses to the surface to form a “floating island”, and Mg can only react on the surface of the TiO2 particle groups and cannot react with each TiO2 particle alone
Summary
Titanium is one of the most important bulk commercial metals, and the current titanium industry is based on titanium sponge produced by the high-pollution, high-energy, non-continuous Kroll process [1]. Based on the thermodynamic evolution of TiO2 reduction and the chemical potential of different reducing agents, a new idea of multi-stage deep reduction to prepare titanium/titanium alloy was proposed [23], First, TiO2 is subjected to magnesium thermal reduction (self-propagating high-temperature synthesis mode, SHS mode) to obtain the non-stoichiometric low-valent titanium oxide containing MgO by-product, that is, primary reduction; the primary reduction product is subjected to calcium thermal reduction to obtain the deep reduction product containing CaO by-product, that is, deep reduction. The Mg-TiO2 SHS system (primary reduction reaction) was studied, and the research was focused on the effect of sample preparation pressure on the primary reduction process and the evolution of low-valent titanium oxide
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
