Magnesium condensate recovered from carbothermic magnesium experimental rig.

Magnesium metallurgy at the speed of sound

A successful direct carbothermic reduction process to produce magnesium metal could result in much greater energy efficiency and capital productivity than is attained using any existing processes.

Research Scientist Dr Geoff Brooks, of the Light Metals Flagship, says that, while the system is still in the early stages of development, the research team is very pleased about their recent breakthrough in producing magnesium metal. “We will now be focusing on improving recovery and purity.”

The technique involves the reduction of magnesium oxide by carbon to produce magnesium metal as a vapour and carbon monoxide gas. Building on a concept first identified in Japan, the new system involves rapidly quenching the magnesium vapour through a laval nozzle at supersonic velocity.

“ We are achieving supersonic speeds in the nozzle and cooling rates above 100,000 degrees Celsius/second, to avoid reversion of the magnesium vapour to magnesium oxide. This really is rocket science,” Dr Brooks says.

Any new technique would need to be fully cost-competitive with current processes such as the Pidgeon and electrolytic approaches, a requirement which Dr Brooks believes would be met by the carbothermic reduction process. “Calculations indicate this process compares well with existing processes,” he says.

The research team is now developing a process flow sheet for scaling up the system, and expects to start designing a pilot plant as the next stage. “The work has reached a very exciting stage and we are quite optimistic that we can develop a working process for producing magnesium that utilises carbon directly,” Dr Brooks says.

These developments will be the subject of a magnesium industry briefing to be hosted by CSIRO in November this year.

CONTACT:

Geoff.Brooks@csiro.au

Ph +61 3 9545 8544

The Light Metals Flagship is a CSIRO initiative and part of the National Research Flagships program that aims to deliver scientific solutions to advance Australia's most important national objectives. One of the largest scientific initiatives ever mounted in Australia, it aligns closely with the Federal Government's National Research Priorities. The initiative brings together our national research resources to deliver breakthroughs in fields ranging from healthcare to light metals and the environment.

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