Pulp bleaching with FAS

Formamidine sulfinic acid (FAS) has been attracting attention as a new bleaching agent in the pulp and paper industry. Though FAS is less powerful for reducing groups of pulp than hydrosulfite, it works effectively for decoloring dyes in pulp suspension. As recycled fiber is more commonly used, and ingredients such as inks and fillers originating from reclaimed papers gets diverse, FAS becomes interesting to the industry. The author shows that the two stage bleaching with hydrogen peroxide and FAS is very efficient for those troubles.