OCC plants convert recycled old corrugated containers into pulp that can be used on paper and board machines to make valuable pulp and paper products. After repulping, the OCC pulp contains some contaminants, such as staples, glass debris, and sand, as well as fiber flakes and bundles that were not separated into individual fibers during repulping. To remove these undesirable materials, the pulp slurry goes through one or more screening processes to remove the contaminants that are larger than fibers. This course describes the second, "fine screening" process used to remove the smaller, more flexible contaminants from the OCC pulp.
Learning Objectives
At the end of this module, you will be able to:
- Explain the purpose of fine screening
- Explain why centrifugal cleaners are often used ahead of fine screens
- Describe why fine screening systems often use multiple stages
- Identify and describe major components of a cylindrical fine pressure screen
- Describe the process flows for fine screening
- List two important geometries for bar-type screen baskets
- List safety hazards and guidelines associated with fine screening systems