The importance and demand for titanium are increasing worldwide. A big market could be opened,
but the development of new applications is constrained by the high costs for titanium. The Kroll
process is the only available method to produce titanium in large-scale quantities.
The need for a cheaper and quicker process has encouraged the research in various alternative
methods. A study performed in 2004 by the US Department of Energy [11] identified 16 different
techniques that are actually being developed. Some promising new approaches could reduce the
cost for titanium by as much as 30 to 50 %. The main objective is to develop alternative procedures
reducing the number of steps of the Kroll-process either by combining some of them in only one
step or by completely substituting them. The main targets are to obtain a product of high purity,
especially with a low oxygen content, to receive a marketable form of the final product (powder,
sponge,…) and to reach a continuous process. In the past many kind of researches have been
conducted but all of them failed.
This article will give an overview over the actual state of art of the titanium molten salt electrolysis
processes, their advantages and disadvantages as well as problems and expectations. The definition
for an electrolytic process is used in a broader sense, i.e. containing an electrolysis even if it is not
directly for titanium. These approaches can be structured in:
• electrolytic reduction of TiCl 4 in a molten salt bath
• direct calciothermic reduction of TiO 2 in a molten CaCl 2 -bath
• direct winning by electrolysing a titanium raw material-carbon-anode
• electronically mediated reaction without direct contact between the titanium raw material
and the reductant.
The raw materials can be Ti-chlorides, Ti-carbides, Ti-oxides or other Ti-compounds. The molten
salt bath composition varies, often including NaCl, KCl, CaCl 2 or MgCl 2 . The results regarding
purity of the metal are partially very promising. Most procedures are still in the very beginning of
the research while others already have been scaled-up to pre-commercial pilot plants.
