| 摘要 |
Bleaching of cellulosic fibrous material e.g. wood pulp, is claimed in an aq. suspension, using chlorine dioxide and chlorine. The chlorine dioxide constitutes 20-95% of the total available chlorine used. The suspension is subjected to a first bleaching step using an aq. soln. of chlorine dioxide and chlorine. Without an intermediate washing step the suspension is subjected to a second bleaching step using chlorine. Method is partic. useful for bleaching of wood pulp suspensions contg. dissolved organic material as a contaminant. By use of the sequential addn. of bleaching chemicals enhanced bleaching of the pulp is obtd. In practice, however, the method facilitates the use of less overall bleaching agent. |
