Useful and economic solutions for the industry
Mineral fillers are fine grained materials, less than 2mm in size that are mined for producing primary fillers, such as kaolin and calcium carbonate. These primary fillers exhibit increased quality characteristics, such as brightness level and rheological properties. Therefore, they are used in many applications where high grade fillers are required, such as communications paper and household paints. Nevertheless, the extraction and processing of these fillers are very expensive procedures that make them extremely costly materials. On the other hand, crushed rock aggregate quarries output large quantities of mineral residues. Currently this valuable fine-grained material is almost non-exploitable and at the same time environmentally unfriendly. Taking the initiative to utilise these fine mineral residues, the efforts of this project focused on the production of more economical BPFs (By-Product Fillers) as an alternative to the costly primary fillers. Additionally, a novel grinding technique, called the Vortex Grinder, was extensively tested for reducing the particle size in order to upgrade the value of the residues along with their uses. The main sources of these BPFs were mineral residues of two major crushed rock types, the siliceous and the calcareous. The developed BPFs were used in a number of applications where the requirements of the fillers quality are less significant. Such applications involve elastomeric membranes, paints, GRP, paper, asphalt, concrete, sub-base and artificial soil. With the aid of the Vortex Grinder the project partners not only produced fine powder from large particles but they also accomplished to reduce the mean particle size of fine powders. The benefits from the project are tremendous. Indicative figures show that a 0.5% of the residues produced each year within EU would generate ECU 32 million per year for the quarry operators and over ECU 10 million per year for the user industries. Therefore, the potential of the BPFs to replace the primary fillers is expected to boost the European industry's competitiveness for both producers and users of BPFs.
