Direct Borohydride Injection (DBI), using ChromaClear? 1000 solution, is a new technology for thereductive bleaching and color stripping of recycle fibers. The use of this process is growing in recyclemills worldwide. The key elements of the process are the sequential addition of sodium bisulfite andsodium borohydride solutions into the pulp stream via medium-consistency or high consistency mixingequipment.This paper summarizes the plant-scale operation and economic benefits obtained by recycle mills in theUnited States and Latin America. The data presented show benefits over traditional reductive technologies.These benefits include: higher brightness, improved color stripping, and substantial application costsavings.Although Borohydride-based bleaching and colorstripping is a simple reductive bleaching technology, theunique borohydride process chemistry provides the potential for significant reductions in application costwhile easily meeting mill quality targets. The borohydride process also offers the potential to increase thebrightness ceiling at equivalent application costs.
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