Australian technology which harvests molten iron blast furnace slag and converts it into a granulated blast furnace slag make cement is being trialled in China where 60% of the world’s iron blast furnace slag is produced. The process is considered environmentally within metal production, called Dry Slag Granulation (DSG), reduces water use and cuts greenhouse gas emissions.

An agreement between CSIRO and the Beijing MCC Equipment Research & Design Corporation Ltd is a landmark in Australia-China research collaboration, according to CSIRO Director of the Mineral Resources Flagship, Jonathan Law. “Our collaboration is an exciting step towards the uptake of an innovation with real prospects of transforming the productivity and environmental performance of global iron smelting,” Mr Law said.

The DSG technology includes a spinning disc and granulation chamber which separates molten slag into droplets under centrifugal forces, uses air to quench and solidify the droplets and extracts a granulated slag product as well as heated air.

The process produces a glassy product ideal for cement manufacture but has significantly lower associated greenhouse gas emissions than cement produced by conventional methods.

“The benefits each year from full commercialisation and adoption of DSG technology are in the order of 60 billion litres of water, 800 petajoules of heat energy and 60 million tonnes of greenhouse gas emissions,” Mr Law said. Those savings are equivalent to 14% of Australia’s energy use and about 10% of our greenhouse gas emissions each year.

China produces 60% of the world’s 300 million tonnes of iron blast furnace slag each year.

Under the agreement, MCCE is to scale-up and demonstrate the technology at industrial scale and will then commercialise it in China and potentially worldwide. The agreement is the culmination of more than a decade of development by CSIRO and industry partners including Arrium and BlueScope.

The Australasian (iron & steel) Slag Association and its members (including CSIRO) have worked together over many years providing assistance with slag samples for trials and forum with its National Technical and Education Committee to discuss the technology developments.