EFFLUENT CHARACTERISTICS AND PULP PROPERTIES FROM THE SOFTWOOD TMP PEROXIDE BLEACHING PROCESS BY PARTIALLY SUBSTITUTING MgO FOR NaOH
Sodium hydroxide is the primary alkali source in the peroxide bleaching of HYPs. While the strong alkalinity of sodium hydroxide can increase the non-effective decomposition of peroxide, and cause the decomposition of partial carbohydrates in pulp. Meanwhile, the strong alkalinity of NaOH can still lead to the formation of new chromogenic groups in lignin structure units that is the alkali-induced darkening, so the brightness of the bleached HYP is decreased. In this work, we investigated the effluent characteristics and pulp properties from the softwood TMP bleaching process by substituting MgO for NaOH. However, the changes in pH value of the residual bleaching liquor and also the resultant TMP pulps with and without MgO substitution were investigated to explore the potential advantages of the process. The results showedthat the addition of MgO could make the alkalinity of whole bleaching system weak. The pH, CODCr, cationic demand and conductivity of the effluent decreased with the substitution percentage of MgO for NaOH increasing. Meanwhile, both the opacity and bulk of the pulps increased, but the tensile index decreased.
TMP Magnesium Alkalinity Effluent load
Qingxi Hou Linyong Ye Rui Song Junhua Zhang Huan Zhao
Tianjin Key Laboratory of Pulp & Paper,Tianjin University of Science&Technology,Tianjin 300457,China
国际会议
International Mechanical Pulping Conference 2011(2011国际机械浆学术会议)
西安
英文
36-39
2011-06-26（万方平台首次上网日期，不代表论文的发表时间）