EFFECT OF SULFIDITY IN ALKALINE PULPING OF WHITE SPRUCE WITH ANTHRAQUINONE

In the soda-AQ and kraft-AQ pulping of eastern white spruce within the screened-pulp permanganate number range 10 to 30, line slopes of the total pulp yield-permanganate number regression equations were different for the two processes and were independent of AW charge. Total pulp yield increased with sulfidity in kraft pulping but was unaffected by sulfidity in kraft-AQ pulping. In soda-AQ and kraft-AQ pulping, using small amounts of AQ, the permanganate number vs. log//1//0H factor regression equations had a common slope, but the intercepts varied with sulfidity and AQ charge. Substantial reductions in effective alkali consumption ta constant pulp permanganate number were observed with increasing sulfidity and AQ charge.