Introduction to the Novel Plate for Manufacturing Thermomechanical Pulp

Abstract

Refiner plates for manufacturing thermomechanical pulp (TMP) exhibit heavy and blunt-bar edges because they are manufactured via casting. Thus, replacing a cast plate that has exhausted its service life is time-consuming and a large amount of energy is required to reach the target freeness. To overcome the limitations of conventional cast plates for manufacturing TMP and chemi-TMP (CTMP), new dissimilar metal-joining technology was applied to lighten the TMP plate. A lightweight aluminum alloy was used as the base of the plate, and stainless steel alloy exhibiting excellent wear resistance was used as the bars. The lightweight plate, which was manufactured by inserting the bars into the base plate, can reduce the weight of the plate by up to a quarter compared with the cast plate. The refining performance of the lightweight plate was also similar or better than those of the cast plate. Particularly, the target freeness can be reached faster because the bar edge of the lightweight plate of a vertical bar shape was sharper than those of cast bars with a draft angle. This lightweight TMP plate obtained better results than the cast plates regarding the raw material throughput, shives content, and strength property development. However, the brightness of TMP and CTMP in the lightweight plate were slightly lower compared with those in the cast plate.