Low carbon cement facility to use old power station fly ash

A plan to build a low-carbon cement facility in regional South Australia is on the brink of reality, with Hallett Group seeking tenders for the design and construction of its first stage.

The $125 million “Green Cement Transformation Project” will process industrial waste into low-carbon cement products at a plant to be built at Port Augusta in the state’s Mid-North.

This project will use locally sourced renewable energy and recycle old coal power plant tailings. It is building a receival hub in Adelaide.

The distribution centre development suffered a setback this week following when the inflatable skin of its 42-metre tall Dome silo at Port Adelaide collapsed, but the company says it will proceed with the project as soon as practical.

“The inflatable skin of the dome is purely the outer formwork for the soon to be constructed primary structure made from 17,000 tonnes of concrete and 2000 tonnes of steel and will be capable of storing up to 52,000 tonnes of cement,” the company says.

“The construction technique of using an inflatable dome skin followed by an internal concrete structure has been successfully performed over two thousand times around the globe. 

“While the structure’s collapse is a step backwards, Hallett will complete the investigation, correct the issues and proceed with the project as soon as practical.”

Hallett Group is the largest integrated supplier of building and construction materials in South Australia.”

The company describes the cement transformation project as: “…the most significant carbon reduction innovation project ever contemplated in the Australian cement and concrete industry.”

Cement manufacturing is one of the world’s worst carbon-generating industries. Some estimates put the figure at three billion tonnes of carbon dioxide a year, or eight per cent of total emissions.

But concrete is also the foundation stone of modern civilisation. And no viable alternative is available.

Also in Cosmos: low carbon cement alternative

“The project will reduce Australian CO2 emissions of 300,000 tonnes per annum immediately, growing to approximately 1 million tonnes per annum in years to come,” a Hallett statement reads.

It aims to do so by cutting the use of traditional cement clinker, produced by fusing limestone and clay in an energy-intensive kiln, by more than half.

Hallett Group is seeking to commission a modular processing facility to dry and screen fly ash (a by-product of coal combustion in power stations) sourced from Port Augusta’s ash storage area at Port Playford. The city was the site of several major coal-fired power plants between 1954 and 2016, and the future of the tailings mounds has been a source of ongoing community concern.

The plant will process 500,000 tons of fine and coarse fly ash annually as an alternative to clinker. It will be operational by June 2024.

Port augusta
A concept image outlining the Hallett Group’s Port Augusta fly ash processing facility.

Project Director Matthew Tidswell say further re-grinding facilities will be added to the site “should the need arise”. He says that existing port and rail facilities at Port Augusta and Port Adelaide, as well as regional wind and solar power generation, contribute to the project’s viability.

Australia uses about 12 million tonnes of cement per year. Nearly half of this is imported as powdered clinker.

For every tonne of clinker to come out of a kiln, 0.87 tons of CO2 is produced through the fusing process. But the fly ash waste from Port Augusta’s decommissioned power stations has already been “baked” to a suitable degree to generate certain clinker grades.

Hallett says it also hopes to use slag waste from Port Pirie’s Nyrstar multi-metals smelter.

“With existing material reserves and ongoing production offtake Hallett can provide the market with 30 million tons of supplementary cementitious materials (clinker replacement) over the next 20 years and beyond.”

A cement blending and distribution hub is also planned for Port Adelaide. Its 52,000-ton cement storage dome and 15,000-ton storage sheds will mix local and imported clinker to suit customer needs.

Tenders for the design and construction of the Port Augusta fly ash processing plant close on February 24. 

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