Cementing change in a concrete world

Calgary startup is developing a way to create a low-carbon version of the widely-used material

- JOHN LORINC

The grey mountains of slag piled high by Hamilton’s hulking steel mills are a salient reminder of the vast amount of byproducts created in the production of industrial materials.

The infernally hot process of transforming pig iron and scrap metal into goods like steel wire or beams produce two types of material: iron slag, the chunky mineral residue created by firing iron ore and coke, and then something called “basic oxygen furnace slag,” a cast-off produced during the process to remove impurities. While there’s a robust market for the former, there’s less demand for the latter, apart from low-end applications like aggregate for road construction. Steel mills generate hundreds of thousands of tonnes of it each year, and the bulk of it ends up in landfills.

Heavy industries like steel, coalfired power plants and cement production are energy and resource intensive, and they release enormous amounts of greenhouse gas into the atmosphere. To shrink the carbon footprint of some of the most widely used materials on the planet, we need to think about not only greening the energy that drives these sectors but also finding new ways to make the best use of the wastes they leave behind.

“Stelco produces half a million tonnes of basic oxygen furnace slag a year,” notes Apoorv Sinha, CEO of a Calgary-based Carbon Upcycling, a startup that’s developing methods to capture and recycle carbon emissions from industrial waste and turn it into low-carbon cement and other materials. “That product currently does not have a great use case.”

That’s something Sinha is working to fix.

A decade ago, Sinha set out to leverage chemistry to create new materials from upcycled industrial waste. It is, he acknowledges, a complicated proposition. Whatever he builds needs to work seamlessly with gigantic plants that have finely calibrated processes and specialized equipment that can’t be radically modified.