What is the first step in the Kraft process?

The first step in the Kraft process involves mixing wood chips with sodium hydroxide and sodium sulfide to create a cooking liquor, often referred to as white liquor. This step is crucial as it initiates the chemical reactions necessary for breaking down the lignin in wood, effectively separating the cellulose fibers that are used to make paper products. Sodium hydroxide provides the necessary alkalinity while sodium sulfide facilitates the removal of lignin, enhancing the delignification of the wood chips.

This initial chemical treatment is vital for ensuring the effective pulping of wood, leading to higher pulp quality and better paper production efficiency. The other options represent subsequent steps in the Kraft process or relate to other stages in the overall pulping process, making them less relevant as the first step.