2023-09-06 06:52:00
The brick industry is trying to shake off its polluting character. Leaders in the sector promise to come up with ‘green’ bricks soon, to build houses and offices with.
The Belgian Vandersanden, also owner of Dutch brick factories, takes the cake. The company announced on Tuesday a new production line for bricks containing CO2 ‘move away’.
The trump card that the group claims to have for this: gasless stone production, with CO2 as raw material. Without the traditional ovens, known as gas guzzlers, with a large CO2footprint.
The ‘revolutionary’ stone must roll off the belt in early 2024 in a new Belgian factory, which is still under construction. That factory will not have ovens, but ‘climate chambers’. There the narrow stone mixtures pressed into molds are dried and hardened in 48 hours.
Chemical reaction
The sealed space will be filled with carbon dioxide, CO2 So. This causes a chemical reaction in which the hardening stones store carbon. “And that forever”, emphasizes Vandersanden.
Each stone would absorb and trap around 60 kilograms of greenhouse gases as it dried. The company therefore refers to a ‘CO2negative stone. The CO2 is supplied by industrial companies, so that the greenhouse gas does not end up in the air.
The factory must have a production capacity of 20 million bricks, out of Vandersanden’s total company production of 550 million bricks. Gasless technology saves a lot of money.
According to Vandersanden, the stone can also be called green because it is made from a mixture of which ‘only’ 20 percent consists of newly extracted sand, water and dye. The rest, by far the most, is a paste of residual flows from the industry.
The gas-free technology has been tested and proven over the past five years, says a spokesperson for the company. What remains is a considerable need for electricity to press and dry the sustainable stone mixtures using fans. The company wants to get the required power from its own solar and wind projects.
Old toilet bowls
Other stone manufacturers are not sitting still either. Spurred on by sustainable requirements and high natural gas prices, they are exploring alternative methods.
For example, the Dutch company StoneCyling, which collaborates with the Zilverschoon Randwijk brick factory in Heteren, promises a production line for bricks that consist of at least 80 percent waste streams. In that case: building rubble, old toilet bowls and old bricks from demolition projects.
StoneCycling, founded more than ten years ago, wants to open a factory in the Netherlands in 2026, which can produce at least 25 million sustainable bricks annually. Unlike Vandersanden, the company will work with an oven that must be able to heat up to a thousand degrees.
“We are focusing on green hydrogen as a fuel,” says spokesperson Esther Kransen. The gas oven is still on for the green bricks that StoneCycling is already having produced on a small scale in Heteren. “We do use green gas,” says Kransen. The bricks are still considerably more expensive than average bricks, she confirms.
Recycling raw materials can be useful
Jan Kadijk, expert in sustainable construction, thinks the initiative for CO2storage in bricks is a good step towards a more sustainable working method. Recycling raw materials can also be useful, says Kadijk, who is affiliated with the Dutch Green Building Council.
Kadijk has reservations about baking ‘green’ bricks in an oven that exchanges natural gas for green hydrogen. “You can make green hydrogen from sustainable electricity. Green electricity is scarce and valuable, the question is what you want to do with it in the future.”
Kadijk doesn’t necessarily think it’s a logical idea to fire a brick oven with it. “Do we really need bricks?” New sustainable trends, in which wood and vegetable and circular facade materials are used, prove that the answer is sometimes: no. “Bricks partly have a cultural value. But to what extent they fit within the sustainable construction future remains to be seen.”
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