Researchers in Spain have mixed paper industry waste with ceramic material used in the construction industry and created a brick that has low thermal conductivity and so is a good insulator.
What's the catch? Its mechanical resistance still requires improvement.
The scientists collected cellulous waste from a paper factory (recycled) along with sludge from the purification of its waste water. In their laboratory they then mixed this material with clay used in construction and passed the mixture through a pressure and extrusion machine to obtain bricks.
"Adding waste means that the end product has low thermal conductivity and is therefore a good insulator," explains Carmen Martínez, researcher at the University of Jaen. "In addition to the resulting benefit of using these bricks instead of their traditional counterparts made of traditional raw materials."
Another of the advantages of adding waste to the brick prototypes is that they provide energy due to their organic material content. This could help to reduce fuel consumption and kiln time required for brick production.
At the moment the prototype's dimensions are small (3 x 1 x 6 cm). But the team has already tested larger bricks and the results are similar. "On the whole, this technique could bring about a saving in energy and raw materials for brick factories along with environmental benefits from the use of waste that is initially discarded," adds Martínez.
Their lower mechanical resistance compared to traditional bricks is a concern and there are still a few problems to solve in the adherence and shaping of those pieces that have high percentages of paper waste, so the team continues in their search for the happy medium between sustainability and material resistance and is still researching the advantages of adding other products, such as sludge from water treatment plants or residues from the beer, olive and biodiesel industries.
The same researchers have published another study confirming that biodiesel waste can be used for brick manufacture, thus increasing insulation capacity by 40%.