After cooking wood chips in the Kraft process, what is the result?

In the Kraft process, wood chips are subjected to cooking with a chemical mixture, primarily containing sodium hydroxide and sodium sulfide. This treatment breaks down the lignin and hemicellulose that bind the cellulose fibers together in the wood, allowing for the production of pulp.

The correct answer is strong black liquor, which results from this cooking process. This black liquor contains organic material and inorganic chemicals that are dissolved during the cooking. It is a concentrated solution that contains the byproducts of the cooking process, including spent cooking chemicals and dissolved lignin.

Understanding why this is the outcome allows for recognizing the significance of strong black liquor in the Kraft process. It is typically further processed by recovery boilers to recover the chemicals used in the pulping process and to generate energy.

Weak black liquor, on the other hand, is produced when water is added to strong black liquor. Green liquor is formed in the recovery process when the strong black liquor is processed further to retrieve the inorganic chemicals. Pulp is the desired product of the Kraft process and is created after the cooking and washing of the wood chips, where most of the lignin has been removed.

Therefore, the result of cooking wood chips in the Kraft process is strong black liquor, essential for the subsequent