| Abstract:Unbleached wheat straw pulps with different Kappa number were bleached by DQP bleaching sequence under the same Kappa factor, and the bleaching effluent load and pulp properties were evaluated. The results showed that the CODCr、BOD5 and AOX loads of the bleaching effluent became lower as the Kappa number of the unbleached pulp was lower, and at the same time the brightness of the bleached pulp became higher. And CODCr and BOD5 increased by about 2.6 kg/t pulp and 0.6 kg/t pulp respectively when Kappa number of the unbleached pulp increased each one unit; the AOX was in the range of 0.5~0.7 kg/t pulp, which was considerably lower than the AOX load of the traditional CEH bleaching. The paper strength was good after DQP bleaching, and the higher the Kappa number of unbleached pulp was, the better the paper strength properties were. |
