|
|
|
|
|
|
|
|
|
| CSIRO | SOLVE | Issue 8 | Aug 06 | |
|
| ||
|
ARTICLE
LIGHT METALS:
Process Innovation to Create New Metals Industry By Whitney MacDonald
Revolutionary technology emerging from the Light Metals Flagship could open the door to a competitive titanium industry in AustraliaAustralia is on the brink of developing a new metals industry through locally developed technology that will make titanium – one of the most versatile light metals known – far more accessible to manufacturers. Although Australia already has the world’s largest economic reserves of titanium ore and is a leading exporter, the cost and complexity of processing this ore has deterred the development of a local, integrated titanium metal industry. However, over the past few years CSIRO researchers have been developing a new processing technology that now looks able to halve titanium processing costs. The development arises from research by the Light Metals Flagship (LMF) – an Australian Government-funded CSIRO initiative involving industry and research partners – that aims to strengthen existing light metals industries, such as aluminium and magnesium, and create an opening for a titanium industry. Titanium metal is unique, being as strong as steel but 40 per cent lighter. It is also resistant to corrosion and it is bio-inert, which is why it is the material of choice for human joint replacements. These properties make titanium an ideal material for use in products where the strength-to-weight ratio and corrosion resistance are paramount. However, until now, the high cost and complexity of processing and producing titanium has limited its use to specialised industries such as the aerospace and biochemical sectors, where the cost can be justified by the benefits. The LMF aims to open the door to an Australian titanium industry by working across the value chain to make such an industry economically feasible. Its emphasis is on research and development that offers step changes in business value. The LMF multidisciplinary strategy includes:
One of the keys to reducing the cost of producing titanium is TiRO™, a new processing technique developed by the LMF. TiRO™ is based on the same chemistry as the Kroll process – the traditional method for producing titanium metal – but is continuous, faster and eliminates many intermediate steps.
Through another LMF project, Dr Graham Sparrow, a project leader in mineral sands research at CSIRO Minerals, is working to reduce the impurities in the starting material – rutile from mineral sands – to produce a purer titania (TiO2) feedstock for more efficient production of titanium metal. “We have been able to reduce the impurities in the starting material from five per cent to about one per cent, which represents a substantial reduction,” Dr Sparrow says. Dr Grant Wellwood, a senior process engineer leading the TiRO™ project, says the Kroll process not only generates a lot of waste, but is also very expensive. “The current processes associated with titanium metal are inefficient. Compounding the metal production inefficiencies are those associated with downstream manufacturing. For example, in many cases it takes up to 10 kilograms of metal to produce 1 kg of manufactured product. While the waste is usually recycled, the rework cost is significant. In aerospace, the ratio is even higher with ‘buy-to-fly’ ratios of 15:1. “A more efficient approach for many non-aerospace applications is near-net-shape manufacture based on powder metallurgy. However, on a per-kilogram basis, the titanium powders needed to facilitate powder metallurgy are currently more expensive than conventional finished products. So, while titanium is a candidate for relatively inexpensive and well-established powder metallurgy techniques, the high cost of first producing the titanium in a powder form makes it unviable.” By directly producing titanium metal in powder form, the TiRO™ process should facilitate near-net-shape manufacture and reduce fabrication cost, enabling titanium to compete with more mainstream materials such as high-end stainless steels. In parallel with TiRO™, the LMF is developing an innovative technology for more efficient and cost-effective production of titanium alloys, a project led by Dr Jawad Haidar. The market for titanium alloys is about 50 per cent of the total titanium market and titanium alloys have a higher value than pure titanium. Unlike the current technology, which involves mixing, melting and recasting metals, the LMF’s technology can directly produce alloys from the raw materials. “Technical–economic analysis of our technology predicts a cost reduction factor of 10 compared to current costs of producing such alloys,” Dr Haidar says. The technology – based on reduction of titanium chemicals with aluminium – has produced 150 grams of alloy per hour in a continuous production mode in a small experimental unit. Plans are under way to move up to a larger lab-scale pilot plant. “The reactions are direct and simple and process times are also shorter,” Dr Haidar says. “The result is that this process can reduce production and capital costs. The Flagship is looking for an industry partner to scale up this research.” Lower-cost titanium metal is the key to facilitating new manufacturing processes. Making thin titanium sheet directly from powder – described as ‘the holy grail’ of titanium manufacture – is another challenge taken on by the Flagship. "Using titanium rather than steel offers a particular advantage to the automotive industry" Project leader Nigel Stone says a key attribute of the process is continuous production. “A number of companies make sheet by direct powder-rolling, followed by conventional and costly batch sintering, but the CSIRO technology is the only continuous process I am aware of.” The process eliminates a host of intermediate steps and reduces overall costs. “Our integrated, continuous, direct rolling process avoids the high costs involved with batch sintering and promises to halve sheet costs. If we get the cost down, the market will flourish,” he says. Industry experts estimate that a reduction of around $3/kg in the cost of titanium metal could double the market for non-aerospace applications. For example, marine industries would have a high demand for low-cost thin titanium sheet in the manufacture of corrosion-resistant equipment. The LMF has also successfully used cold spray technology to directly fabricate titanium components such as ball valves and pipes. Cold spray requires no intermediate processing or hazardous chemicals, and uses less energy and water than current fabrication processes. Dr Sami El-Soudani, from the Boeing Company’s Phantom Works advanced R&D division in California, says new processes represent an opportunity to offset titanium’s supply/demand imbalance. “Given that only five per cent of titanium ore is used for metallic titanium, with the balance of 95 per cent being consumed by the paint industry, there is a golden opportunity to offset this imbalance in favour of increased metallic titanium production in order to meet crucial demands of the various industries, spearheaded by aircraft industry needs,” Dr El-Soudani says. “If successful, this could reduce the cost of titanium per pound to levels comparable with those of stainless steel and aluminium, at a considerably increased volume of titanium used.” Titanium also scores highly in terms of lifecycle analysis, where factors including the useful life of the component and the value of its lighter weight over this period are considered. Using titanium rather than steel offers a particular advantage to the automotive industry, where the incorporation of titanium in cars would translate into reduced fuel use and greenhouse gas emissions. LMF director Dr Raj Rajakumar says CSIRO’s research and development initiatives are making tremendous progress in reducing the cost of titanium and titanium products through novel technology and innovation. “This is reducing the investment risk associated with a local industry. This risk reduction is important because the typical investment required to establish these industries is very high.” Stan Seagle, from the International Titanium Association, says the scope and extent of efforts by CSIRO and other Australian companies related to titanium metal production is impressive, and that cost-reducing technology will accelerate the demand for titanium. “Australia, with its large reserves of titanium minerals and a well-developed mining industry, is in a good position to capitalise on this potential through the availability of ores and the downstream processing that could evolve from the new technology,” he says. APPLICATION The use of titanium may now be feasible in industries beyond specialised ones such as aerospace and biochemical sectors BENEFIT New processing technology has the potential to halve titanium processing costs For further information contact: |
 IN THIS ISSUE
|
| Home | About Us | eSubscribe | Links | |
|
|
||
|
|
|
Back to main