Outside of the industry it is often assumed that most titanium bearing ores such as ilmenite and rutile are turned into titanium metal (for well known applications in aerospace and medical implants due to its high strength and low weight). In fact 95% of titanium is used as the oxide in pigments for paints, plastics and papers. Only 5% is turned into ingot, first as titanium sponge, then through two melting steps before it arrives at titanium ingot before further rolling or forging to semi finished products. These downstream applications are a major part of the cost of producing titanium components and if the purification and processing costs could be significantly reduced it would open up a huge market for titanium’s unique properties that at the moment are not viable due to the high cost of traditional production routes.
Or so goes the thinking of Australia’s CSIRO Minerals who are running laboratory trials on a new fluidized bed process that works at lower temperatures than the traditional Kroll process and produces discrete titanium particles which can be separated in a second stage. In current trials, a batch distillation process is employed for separation but in commercial production a continuous process would be developed. In trials so far, the purity of the Ti particles is comparable with commercially pure Ti grades produced conventionally.
However as illustrated above, a large part of the cost of finished titanium components currently comes from the subsequent fabrication costs. The Australians are looking to solve this issue by exploiting another feature of titanium in powder form and that is its amenability to powder metallurgy (PM) to circumvent a number of the mill based manufacturing processes currently employed. Some titanium products produced via the PM route are already in commercial use but purity of the source powders, particularly residual hydrogen, is an issue that prevents wider adoption. However if CSIRO’s alternative production route can achieve, as seems likely, the low levels of impurities required, this could not only open up a lower cost production route for powder but the lower cost PM and sintering production route for finished components.