4. Conclusion

This article summarizes the main phenomena and mechanisms involved in the chemical cooking of wood. The aim of this process is to extract the cellulose fibers from the wood to make paper or products derived from fibers and cellulose. For pulp, kraft cooking is the predominant process (over 90% of mills). Bisulfite cooking produces special pulps and lignosulfonates. Soda cooking is reserved for small units using annual plants.

Lignin, whose annual production today reaches 70 million tonnes, has until now been considered a waste product to be burned, providing mills with the energy they need while recycling mineral reagents for cooking. Only the lignosulfonates produced by bisulfite pulp mills are recycled.

Today, pulp mills are being transformed into biorefineries: an emerging concept over the last ten years, which can be defined as "a global...