Using magnesium hydroxide (Mg(OH) 2 ) as the alkali source in peroxide bleaching at Irving paper

Abstract

Mg(OH)2 was used to replace sodium hydroxide and sodium silicate in a TMP perox- ide bleaching process. Brightness gain with Mg(OH)2 as the sole alkali source is comparable to the caustic/silicate based process. The Mg(OH)2 process produced less anionic trash in the pulp and lower effluent COD content. The sequential addition of chemicals with hydrogen peroxide last was superior to the conventional peroxide bleaching process. Improved economics and performance have been proven in the mill application.