Almatis Gmbh

Calcined Aluminas

Calcined Aluminas

Calcined aluminas are alpha-aluminas that consist primarily of sintered agglomerates of individual alumina crystals. The size of these primary crystals depends upon the degree of calcination and the agglomerate size on the subsequent grinding steps. The majority of calcined aluminas are supplied ground (<63μm) or fine-ground (<45μm). The agglomerates are not fully broken down during the grinding, which is a significant difference from reactive aluminas that are fully ground by a batch grinding process. Calcined aluminas are classified by soda content, particle size and degree of calcination. Ground and fine-ground calcined aluminas are used as a matrix filler to upgrade the product performance of formulations predominantly based on natural raw materials.