The proportion of carbon emissions attributed to the consumption of refractory bricks -- heat-retardant materials used to line smelting furnaces -- is set to become a growing focus for the steel industry, particularly as steelmakers reduce their own direct CO2 emissions and look to make further savings elsewhere in the process.
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Stefan Borgas, CEO of Vienna-headquartered LSE-listed refractory supplier RHI Magnesita, told S&P Global Commodity Insights in a recent interview that companies such as his own are increasingly being encouraged by downstream users to focus on decarbonization and innovation themselves.
Refractory bricks are used in the production of most metals, although the steel sector currently absorbs two-thirds of the market.
At present, refractory-related emissions make up 3-4% of steelmakers' overall carbon footprint. However, as the sector shifts to much greater use of direct reduced iron-electric arc furnace technology from the 2030s, eliminating coal burning and the associated CO2 emissions, the proportion of emissions assigned to the use of refractories could effectively reach 20-35%, Borgas said, at which point it will become an important target for companies seeking to further burnish their green credentials.
"We know of 20 projects [replacing blast furnace-based technology with DRI-EAF] in Europe, six in North America, two in South America, seven or eight in China, three to four in India. There are some in the Middle East, Japan, South Korea, but in a big way, the change away from blast furnace toward EAF will happen after 2030 because its capex is extremely high, and a lot has to be tested first," Borgas said.
The trend will have a moderately positive effect on refractory demand, Borgas said, although he added that the actual total volume of emissions from refractories will likely fall somewhat over the same period, as a result of efficiencies.
Borgas said that global refractory needs for the changing market -- DRI- and EAF-based mills will require more technically advanced products -- can be supplied by existing producers, although he added that India will require extra capacity. At present, refractory demand amounts to some 10 million mt/year.
Some 80% of refractory emissions come from the extraction and calcination of raw materials, with 20% from the manufacturing process, mostly from the burning of fossil fuels to achieve the high temperatures needed to temper refractories.
"For the refractory making, the solution is to replace gas, oil with hydrogen, but to effect the fuel switch we need the countries in which we operate to provide hydrogen," Borgas said.
Borgas said that further savings can be made in the reuse of raw materials from spent refractories.
For example, five years ago, RHI Magnesita was using 2% of recycled content in its products but this has now risen to 13%, but he predicted that this could only exceed 15-17% with new technology.
"Refractories are very complex. We buy 3,000 raw materials to make 300,000 products. When we take them back as waste, the biggest question is how to sort it and get it back into the molecular mineral structure it had before," Borgas said.
The most challenging issue for refractory producers is the capture of CO2 from their output processes.
Borgas said that RHI Magnesita is collaborating with Australian MCi Carbon to turn emissions into solid bulk materials, adding that the two companies want to build a plant at Hochfilzen, Austria, to convert carbon emissions into commercial products, aiming for launch by 2030.
The company also sees the potential of using solar energy at its Brumado plant in Brazil as a way of decarbonizing.
RHI Magnesita's own CO2 emissions have plunged from 5.5 million mt to 4.2 million mt in 2022 as a result of recycling and smarter energy use.