Paper waste used to make "green" bricks
By Ben Coxworth
December 20, 2012
Paper waste has already been used to create things like foam and batteries – now, a team of researchers from Spain’s University of Jaen are making bricks out of the stuff. Although the finished products still need a little tweaking before they're ready for prime time, they could ultimately give traditional bricks a run for their money.
The scientists gathered cellulose waste from a paper mill, along with sludge left over from the purification process of that plant’s waste water. Those substances were then mixed with clay used in building construction, pressurized, and then extruded in one long sausage-like length. The bricks were subsequently sliced from that material, and fired in a kiln.
According to the researchers, the bricks didn’t need to be fired for as long as their conventional counterparts, due to their paper content. If they were being produced commercially, this would result in considerable savings in energy and production costs.
The addition of the paper also caused the bricks to exhibit low thermal conductivity, meaning that they would have good insulating properties if used in a building. Of course, they would also divert a waste product from landfills, and would allow brick-makers to stretch their clay supplies farther.
At just 3 x 1 x 6 cm (1.18 x .39 x 2.36 inches) the existing bricks are quite small, although larger ones have also been created, and reportedly displayed similar qualities. Unfortunately, however, their mechanical resistance isn’t great – so far. Although it’s above the legal minimum, it’s not up there with that of traditional bricks.
The team hope to address this limitation, perhaps by additionally incorporating waste from the beer, olive or biodiesel industries, or sewage sludge. Researchers from Spain’s University of Seville and Glasgow’s University of Strathclyde have also been experimenting with making bricks that are composed partly of surplus sheep’s wool.
A paper on the University of Jaen research was recently published in the journal Fuel Processing Technology.
Source: Plataforma SINC (Spanish)