The Possibilities to Reduce Chlorine Dioxide Consumption in the ECF Bleaching of Bamboo Kraft Pulp, 2004 Engineering, Pulping, and PCE&I Conference

Bamboo (Bambusa procera acher) kraft pulp was first oxygen-delignified and then alternatively bleached using the DE(D/N)D, D(EOP)DP, D(EOP)D(PO), D(EOP)QP or D(EOP)Q(PO) sequences to a brightness level of 88- 90% ISO. The results indicated that, when the E stage in the DE(D/N)D sequence was reinforced with either O2 or H2O2 or simultaneously with both, a significant reduction (20-40%) in ClO2 consumption and a clear increase in the brightness ceiling were obtained. Further savings in ClO2 consumption without loss of viscosity were obtained when the neutralization (N) treatment in the (D/N) stage and the last D stage in the D(EOP)(D/N)D sequence were replaced by either a P or a PO stage. In contrast, it was difficult to obtain a fully bleached pulp by replacing the final (D/N)D stages by either QP or Q(PO) stages. In both the latter cases, the H2O2 charge needed was high and, in addition, significant losses in both viscosity and yield occurred in the PO stage.