Chlorine is an excellent chemical for pulp bleaching because of its low cost and lignin removal effectiveness. For these reasons, chlorine was traditionally used in the first bleaching stage to remove up to 90% of the lignin remaining in unbleached pulp. Chlorination is the treatment of pulp with chlorine to solubilize lignin and ultimately bleach the pulp. This course discusses the basics of chlorine bleaching chemistry, the purpose of extraction, and the equipment used in chlorination and extraction.
Learning Objectives
At the end of this module, you will be able to:
- Define the purpose of extraction
- Describe the variables of extraction
- Describe the safety concerns of sodium hydroxide
- Identify equipment used for extraction
- Describe the role of oxygen and hydrogen peroxide in extraction