Sulphate process paper

The sulphate process (also known as "Kraft digestion" because of the strength of the paper made using it) is the most common process for making paper pulp from cellulose. Lignin contained in the plant material is separated by cooking in an alkaline medium containing sodium sulphate and sodium hydroxide ("white liquor"). The pulp is screened, washed and bleached. By clever combination of process steps, the chemicals used can be largely recovered, with gases increasingly being used here.

Causticizing Lime Kiln Digester