BLEACHING OF MECHANICAL PULP WITH FORMAMIDINE SULFINIC ACID

In this work, we evaluate the potential of a reductive agent, formamid ine sulfinic acid (FAS), for the bleaching of thermomechanical pulp of spruce-balsam. We have studied the efficiency of FAS with different c onditions of time, temperature, consistency and concentration. We have chosen statistical model for the planning of the experimentation in o rder to establish mathematical equation of the brightness as a functio n of these four parameters. The results will be discussed in terms of brightness and color coordinates (reference CIELAB). The analysis of t his model shows that the increase of temperature and concentration of FAS and the decrease of consistency improve the brightness. It is impo rtant to note that the time of the reaction does not seem to have any effect on brightness. A ratio of 0.5% of sodium hydroxide is suitable for 1% for FAS, more than that will increase the yellow shade of the p ulp. We compared results of FAS to conventional bleaching with sodium hydrosulfite; brightness that has been obtained is approximately the s ame.