Ozone Treatments of Bleached Kraft Pulp and Waste Paper

摘要

Commerical bleached kraft pulps were treated by ozone. Changes in the total halogen and ethanol extractable organic halogen of these pulps as well as brithtness, viscosity and the water retention value were investigated during ozone tretment. The effects of ozone treatment of the total halogen and ethanol extractable halogen of waster paper were also studied toner-printed copy paper. The ozone treatment of the chlorine-bleached pulps the waste copy paper were carried out at a 4% (or 30%) pulp consistency any at 10 deg C for 5,10 and 20 min,, respectively. The total halogen and the ethanol extractable organic halogen of the chlorine-bleached pulps were much higher than those of elemental chlorine -free pulps. The ozone treatment substantially reduced both the total halogen and the ethanol extractable organic halogen of the chlorine-bleached pulps. The ozone -treated pulps from the waste copy paper resulted in a lower total halogen compared with the sual deinked pulp. The hardwood bleached pulp with a brightneww showed some increase in brightness after the ozone treatment.Although the pulp viscosity significantly decreased during the ozone treatment. the strength properties of the handsheet from the ozone-trated pulps were slightly changed