Pulp Bleaching

Pulp Bleaching

Sulfite process becomes the dominant method for making wood pulp paper.

Date(s)
1900
Creator
Carl Daniel Ekman
Chemical wood pulp paper is longer lasting and more durable than unprocessed wood pulp paper. Manufacturers used caustic chemicals, originally sulfites, to break down the wood fibers and remove the lignin from the pulp. Chemical pulping made for sturdier paper, but its lifespan was still limited.

By the early 1940s, the Kraft process for making wood pulp paper superceded the earlier sulfite processes, in large part based on the recovery boiler invented by G.H. Tomlinson. The recovery boiler allowed nearly all the chemicals used in the process to be captured and recycled, dramatically increasing efficiency and productivity.

There are very few remaining suflite processing paper mills left in the United States. The sulfite process is responsible for less than 10% of the chemically processed paper available on today's market.
Sources
“Pulping.” PaperOnline. Accessed November 23, 2015. http://www.paperonline.org/ paper-making/paper-production/pulping
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