Researchers at Jaen University in Spain have mixed paper industry waste with a ceramic material used in the construction industry to create a brick with low thermal conductivity.
The scientists, whose research is published in the journal Fuel Processing Technology, collected cellulous waste from a paper factory along with sludge from the purification of its wastewater.
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, in addition to the resulting benefit of using these bricks instead of their traditional counterparts made of traditional raw materials,’ said Carmen Martínez, a researcher at the university.
According to a statement, another of the advantages of adding waste to the brick prototypes is that they provide energy thanks to their organic material content. This could help to reduce fuel consumption and kiln time required for brick production.
The prototype’s dimensions are currently 3 x 1 x 6cm but the team has already tested larger bricks and the results are said to be 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,’ said Martínez.
The researcher acknowledges that the bricks have lower mechanical resistance compared with traditional bricks, although this parameter is above the legal minimum.
There are also challenges to overcome in the adherence and shaping of those pieces that have high percentages of paper waste.
The team is continuing its search for a compromise 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.
In Fuel Processing Technology, the researchers have published another study confirming that biodiesel waste can be used for brick manufacture, increasing insulation capacity by 40 per cent.