Circular action treatment (CAT): a new strategy for mechanical treatment of old corrugated containers II – comparison of CAT with low-consistency beating

Abstract In Korea, old corrugated containers (OCC) are a common material for paperboard production. Unfortunately, the quality of Korean OCC (KOCC) is low due to irreversible effects such as hornification that could occur by repeated drying and wetting during paper recycling. Generally, beating is a fibrillation method for improving paper strength. However, beating also results in fiber shortening and excessive fines. Circular action treatment (CAT) is a new method designed for the mild mechanical treatment of KOCC containing undesirable materials and fines. The effect of CAT and low-consistency beating on KOCC were analyzed at various conditions. The results show that increased revolution speed and passing length of CAT resulted in higher water retention values and paper strength without a sudden change in the freeness, fiber length and fines content. While paper strength was higher upon beating compared to the case of CAT, the intensive beating action in the former resulted in fiber damage, generating excessive fines and decreasing fiber length. The fines generated by beating might be negative to retention and drainage in wet-end. Therefore, CAT is a promising new strategy for KOCC mechanical treatment, and an increase in the revolution speed and passing length of CAT could improve KOCC quality.