New markets for volcanic rock Perlite is a naturally occurring volcanic rock that expands with heat to between four and 20 times its original volume. Novel processing has enabled improved products for the construction, chemical and manufacturing industries. Industrial Technologies © Thinkstock The light weight, porous, chemical- and fire-resistant expanded perlite is an excellent candidate for components in the chemical, construction and manufacturing industries. However, applications have been limited by undesirable attributes created during the conventional expansion process such as pores that are open to the exterior (open porosity). The innovative EU-funded project EXPERL developed new processing technologies leading to innovative, closed-structure perlite-based micro-particles and high added value commercial end-products exploiting them. Scientists improved the expansion process with indirect heating in a vertical electrical furnace and microwave heating. A wet silicon spray treatment was developed to minimise water absorption and multifunctional nanoparticles were used for surface coating of the perlite particles. Five different perlite-based materials were successfully developed within the scope of the four-year project including closed-structure perlite, perlite micro-spheres and expanded perlite flakes. These were used as functional fillers in a variety of industrial applications. Light-weight insulating panels, bricks, plasters and mortars were developed for the construction industry. Researchers created vacuum insulating panels and envelope films for the manufacturing sector. Finally, perlite-based materials were incorporated into novel paints and thermal insulation coatings for the chemical industry. In all cases, life cycle assessments of the production technologies and the new products demonstrated lower environmental impact than those of conventional techniques and products. EXPERL’s 29 exploitable results led to numerous patents and trademarks. Many products are at pilot-scale and others are ready to hit the market. Technology and materials will boost the competitive position of the EU's industrial minerals sector while creating new markets benefitting the construction, chemicals and manufacturing sectors. Keywords Expanded perlite, porosity, chemical, construction, manufacturing, electrical furnace, microwave, nanoparticles
