Wood fiber accounts for more than 90% of the raw material used in the production of paper and board products, and it can come from a variety of sources. These sources can be slushed virgin fiber that is produced onsite, market pulp from other pulp mills, or recycled/secondary fiber. In the "recycled" fiber category, the most difficult source to process is post-consumer waste. This fiber arrives at the mill contaminated with a variety of undesirable materials. This course will focus on how the fibers are cleaned and separated from the contaminants using the two categories of physical separation: centrifugal cleaning and screening.
Learning Objectives
At the end of this module, you will be able to:
- State the purpose of recycled fiber cleaning and screening
- Identify some of the typical contaminants/material found in recycled fiber sources
- List the different techniques used to clean recycled fiber
- Explain the principle of separation for centrifugal cleaning
- Identify the purpose of a high density cleaner
- Identify the main components of a cylindrical screen
- Explain the principle of separation for screening
- Differentiate between coarse and fine screens
- Differentiate between high density and low consistency cleaners
- Differentiate between forward and reverse cleaners