METALS MANAGEMENT IN THE FIBERLINE

摘要

Nonprocess element (NPE) concentrations within the fiberline increase as the degree of bleach plant closure increases. Increased concentrations of calcium and barium can lead to scale deposits on process equipment requiring costly downtime to remove the deposits. Increased concentrations of manganese and iron catalyze the decomposition of hydrogen peroxide leading to reduced bleaching efficiency and/or pulp strength loss in oxygen, ozone, and hydrogen peroxide stages. The open chlorine stage of the conventional bleach plant served as a purge for these NPEs and self-managed metals in the fiberline. Elimination of the chlorine stage and/or closure of the bleach plant water circuits requires controlled purges to manage metals within the fiberline.