소나무로 제조된 열기계펄프의 표백 시 수산화마그네슘의 효과 연구

Abstract

The conventional NaOH-based peroxide bleaching process has been regarded as an effective option in increasing pulp brightness for thermomechanical pulp (TMP). However, as a strong base, NaOH can cause the dissolution of hemicelluloses into the bleaching effluents and is responsible for the increased COD load and the formation of a significant amount of anionic trash. In recognition of several drawbacks associated with the NaOH-based peroxide bleaching process, magnesium dihydroxide as a weak alkaline source was used to replace sodium hydroxide used for peroxide bleaching of TMP made from domestic pine, Pinus densiflora . Brightness gain of BTMP with Mg(OH)2 as the sole alkali source was comparable to the NaOH-based bleaching process. The Mg(OH)2-based bleaching generated less anionic trash as well as lower COD in the bleaching effluents. In conclusion, the change of alkali to Mg(OH)2 may well prove to be an efficient solution to bleach TMP from the softwood without sacrificing brightness.