Production of titanium powder by metallothermic reduction of TiO₂ in cold pressed pellets

Abstract

In order to produce low-cost titanium (Ti) with high productivity, fundamental studies on producing metallic Ti from titanium dioxide (TiO₂) in the cold pressed pellets were conducted by metallothermic reduction with an indirect contact method. This paper focuses on discussing the mechanism of the reduction process and the relationships of R_M (a revised reduction index) with reduction temperature, reduction time, and mole ratio of TiO₂ to CaCl2 (

n_{{\text{TiO}}_2}/n_{{\text{CaCl}}_2}

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) in the pellets. The results show that metallic Ti was obtained from the reduction of TiO₂ in the pellets by calcium (Ca) vapor; pellets were reduced homogenously and Ca vapor diffused into the porous pellets by Knudsen diffusion or the mixing diffusion of molecular diffusion and Knudsen diffusion at 1273 K; R_M increased with the increases of temperature and reduction time and was 96.34% when T_Redu=1273 K, t_Redu=6 h, and

n_{{\text{TiO}}_2}/n_{{\text{CaCl}}_2}=4

\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${n_{{\rm{Ti}}{{\rm{O}}_2}}}/{n_{{\rm{CaC}}{{\rm{l}}_2}}} = 4$$\end{document}

; the reasonable n_TiO2/n_CaCl2 value is 3–5 for the pellets with enough strength and high R_M.

Keywords

titanium dioxide / titanium powder / metellothermic reduction / cold pressed pellet / reduction index

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