Pulping
Pulping is the process where fiber in wood is separated from lignin, washed, and bleached to become white pulp, ready to be processed into paper.
Market Needs
Pulping Process (Kraft Process)
Causticization
Fiber is separated from lignin using cooking liquor (NaOH & Na2S). Sodium hydroxide (NaOH) can be recovered for reuse by lime addition.
Pulp Bleaching
The pulp is bleached using bleaching agents to increase whiteness for white paper production
Solutions
Quicklime
- It is used to recover sodium hydroxide (NaOH) by reacting with the calcium hydroxide produced in the process. A by-product from this reaction (calcium carbonate) can be burned in a kiln, becoming quicklime, and reused
- A raw material used to produce a bleaching agent
