脱果胶试剂在全棉秆化机浆漂白中的应用

Application of Depectinization Agents in Bleaching of Whole Cotton Stalk Chemi-mechanical Pulp

通过原子吸收分光光度计(FAAS)对原料中金属离子含量进行定量分析.以果胶酸钙为模型物,考察氢氧化钠、草酸钠等脱果胶试剂对棉秆皮部的果胶脱除及化学成分的影响,进而探讨改进全棉秆化机浆成浆性能的方法.实验结果表明:各脱果胶试剂与果胶酸钙模型物反应速率的关系为2 2 43 4Na C O NaOHNa POv>v>v;用3%草酸钠进行皮部预处理,棉秆皮部果胶脱除率可达到53.72%.对全棉秆化机浆漂白结果显示,当温度90,℃、草酸钠用量3%的预处理条件下,以6.5%NaOH和11%H2O2制得全棉秆化机浆白度可以达到76.2%,尘埃度可降至50.10,mm2/m2.

The effect of pretreatment on improving the bleachability of whole cotton stalk chemi-mechnical pulp was fo- cused on. The content of metal ions in the raw material was determined with flame atomic absorption spectrometry （FAAS）. The effect of depectinization agents including sodium hydroxide and sodium oxalate on pectin removal and chemical compo- sitions in cotton stalk bark was also studied respectively. The results showed that the reaction rate of depectinization agents against calcium pectate was VNa2C2O4 〉VNa3PO4 〉VNaOH· The ratio of pectin removal could reach 53.72% after pretreatment with 3% sodium oxalate. When the parameters of preconditions were 3% of sodium oxalate, 90℃, and bleached by 6.5% NaOH and 11% H2O2, the brightness of the chemi-mechnical pulp from whole cotton stalk reached 76.2%, and the dirt count was 50.10 mm^2/m^2.