poraSpheres® – The first Hollow Glass Spheres (HGS) from post-consumer recycled glass
The production of poraSpheres® starts October 2022 at the new production site in Schlüsselfeld, Germany (picture 1). The new plant is able to produce more than 30,000 m³/year of poraSpheres® in the first stage and is designed to be easily upgraded to fulfill a growing demand.
Same as the well-known and approved Poraver® functional filler poraSpheres® are made from post-consumer recycled glass, saving natural resources. Different to existing HGS which are made from virgin soda-lime-borosilicate glass, poraSpheres® are made from soda-lime-glass coming to 100 % from the recycling of bottles and container glass. As the used grade of recycling glass cannot be used for the production of new bottles anymore the upcycling to poraSpheres® avoids disposal of valuable glass and unnecessary landscape filling; closing the gap in the glass recycling system.
Since its introduction in 1983 Poraver® is known as a high-quality functional filler for many advanced materials such as panels/boards, ultra-lightweight concrete, adhesives, self-eveling underlayments and many more products. But not only mineral bound systems benefit from the usage of Poraver®, also organic bound systems are getting lighter, less brittle, and less thermal conductive; to name only some of many advantages.
The only product group that is not able to utilize Poraver® are wet premixed materials as the long-term liquid absorption of the multicellular Poraver® leads to a reduced shelf life of the materials.
The new developed poraSpheres® contain only one cavity (picture 2) and have no long-term liquid absorption; they are the perfect fit for premixed acrylic and resin bond system requesting a longer shelf life. Obviously poraSpheres® will reduce the density of those products compared to the usage of normal weight fillers but they will do even more. With their surface texture and spherical shape, they will also improve workability and segregation resistance. Due to the lower Young’s modulus, the final products have an increased deformability and better crack bridging properties.
poraSpheres® are available in three different grain sizes (picture 3) from 90 to 500 µm. The
technical data are shown in table 1.
In addition to the different type of glass used as raw material, existing hollow glass spheres are very fine with a median diameter in the range of only 18 to 65 µm, poraSpheres® will extend the range of hollow glass spheres to 140 to 350 µm (median diameter). With this size poraSpheres® are more in the range of ceramic cenospheres from fly ash, a by-product from coal power plants. Cenospheres offer a high isostatic strength and high softening temperatures but due to their nature, the stability of product quality is limited. For white or coloured products, only special cenospheres can be used, as common grades are dark in colour. In addition, the reduction of coal power plants is reducing their availability.
poraSpheres®, as a technical product based on glass offers a stable product quality within a
tight specification in combination with a high availability. With the three grain sizes available, poraSpheres® offer the formulator the opportunity to design the perfect particle size distribution for the product.
Last but not least, the usage of poraSpheres® is not only limited to wet premixed products.
With the low density due to the single cavity poraSpheres® will significantly reduce the weight of cementitious thin set material and bring those materials to the next level of quality