AUSTRALIA’S CSIRO has teamed up with specialty chemicals company Enirgi Group to develop and commercialise its efficient MagSonic process to make magnesium.
Demand for magnesium is growing, as it is very lightweight. Vehicle and aeroplane manufacturers are increasingly using magnesium alloys to produce lighter parts for great fuel efficiency. The conventional method to make it, the Pidgeon process, uses ferrosilicon to reduce magnesium, but is energy- and labour-intensive and costly. The MagSonic process, which won the IChemE Sustainable Technology Award in 2011, uses up to 80% less energy and produces up to 60% less CO2.
The MagSonic process instead uses carbon to reduce magnesium oxide in a carbothermal reduction. The two materials are combined and formed into briquettes and heated to over 1,700?C in an inert atmosphere, using an induction furnace. The resulting reaction produces magnesium vapour and carbon monoxide. The gases are drawn towards a supersonic nozzle. As the gases pass through at around four times the speed of sound, they are cooled in around 55 ms, condensing and solidifying the magnesium into small particles, which cannot re-react with the carbon monoxide. The magnesium powder travels into a large chamber where it cools completely. After this, a cyclone separates the powder from the gas. The magnesium powder is then cast into slabs, which are less reactive than powder.
Mark Cooksey, the leader of CSIRO’s sustainable process engineering group, tells The Chemical Engineer that at present, the process has been running at laboratory scale, producing around 500 g/h of magnesium. The researchers will now work with Enirgi Group’s innovation division, which has experience in developing new processes, to scale up and commercialise the process. Cooksey says that they hope to build a pilot-scale plant very soon, and that a commercial plant would follow around two years later.
Once the technology is ready for commercialisation, Enirgi Group will have the option to globally license the technology, and plans to build a commercial-scale facility in Australia.
“The growth of magnesium use has been limited because it’s been too expensive and labour-intensive to produce the metal from ore using traditional processes. Our MagSonic technology offers an economically-viable solution to overcome these issues and make clean magnesium more available and affordable to manufacturers,” said Cooksey.
Enirgi Group’s vice president of corporate development, Anthony Deal, says that he is “confident” that the process can be commercialised.
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