Pulverization of fibrous mineral wool waste

The total annual volume of mineral wool waste in the 27 European Union countries is expected to increase to 2.5 million tons per year by 2020. Unfortunately, mineral wool wastes are often considered unrecyclable, because their physical characteristics make them difficult to process. In many cases, the problem is caused by the material’s fibrousness. However, no studies have considered comminution methods for mineral wools. The objective of the present study is to investigate how various comminution mechanisms affect mineral wools’ physical characteristics, including appearance, bulk density, and fiber length and width. The study’s results show that compression-based methods (vibratory disc mill and hydraulic press) completely break down mineral wools’ fibrousness, whereas methods based on high cutting speeds affect bulk density and fiber length only moderately. In addition, the present study identifies a rapid method that can be used in a novel way to analyze a large number of mineral wool fibers.