Titanium Extraction Metallurgy Developments and Control of Impurity Elements

Abstract

Titanium extraction metallurgy poses numerous challenges owing to a combination of various characteristics such as high chemical reactivity, high melting point, strong affinity towards oxygen and nitrogen, pyrophoricity of nascent sponge. Kroll process of magnesium reduction of has become the widely employed titanium sponge production technology. Sodium reduction of TiCl4 known as Hunter’s process has also been employed for the industrial production of titanium sponges for about two decades. Subsequently quoting techno-economic reasons, the Hunter sponge plants across the world have been closed. There have been several efforts over the years to evolve an alternative to the Kroll process mainly to achieve a simple and cost and energy-effective titanium extraction process. Control of impurity elements in the titanium metal during the metal extraction process assumes greater importance as thermodynamics does not favour any purification method to be employed for the metal. This chapter brings out historical developments in titanium extraction metallurgy and highlights recent developments as well to produce high-purity titanium sponges required for titanium alloys for the end applications across various sectors.