DEBRIS IN STONE GROUNDWOOD.

The generation of undesirable material (shives and minishives) in the manufacture of stone groundwood pulp has been examined. It has been shown that the production of debris is influenced by the sharpness of the stone, the degree of pocket imbalance, the applied load, and pit temperature. It was found that stock freeness is a good indicator of debris generation in each individual grinder; however, the specific energy consumption and freeness to reach a given debris level was not the same in different grinders. It has been shown that pulp of a given debris level produced in grinders equipped with larger motors requires higher specific energy. A simple control scheme, based on monitoring individual grinders to produce a stock of an acceptable debris level and to satisfy production and drainage requirements, is discussed.