Sawdust to keep out fire

(CONNECT) Researchers at the Swiss Federal Institute of Technology in Zurich (ETH) and the Swiss Federal Laboratories for Materials Science and Technology (Empa) have developed an insulating material made from sawdust that can be used for fireproof interior construction, according to a press release.

The composite consists of sawdust and the mineral struvite, a crystalline, colorless ammonium magnesium phosphate. In their work, the researchers had to overcome the difficulty of combining the materials with the sawdust particles in the crystallization process of the struvite. This was achieved using an enzyme obtained from watermelon seeds. The crystallized mineral fills the cavities in the sawdust. The resulting material is pressed into sheets and dried at room temperature.

Initial tests have shown that the composition has similar fire protection properties to conventional cement-bonded particleboard. The tests, which were carried out together with the Polytechnic of Turin, showed that the struvite sawdust boards catch fire three times slower than spruce wood. However, inorganic material is formed in the process, which prevents the flames from spreading.

In order to scale up the process and use the new material, it is important to reduce manufacturing costs. Currently, the production of the binder from the mineral is more expensive than polymer binders or cement. This could change with the development of another cycle: struvite is produced in large quantities in sewage treatment plants. "We could use these deposits as a base material for our building material," said Ronny Kürsteiner, a researcher in the wood-based materials department at ETH, in the press release.

The study has been published in the journal Chem Circularity. ce/ww