The slaker mixes clarified green liquor from green liquor clarifiers with fresh and reburned lime to produce white liquor. The slurry created by the reaction of lime slaking in the slaker is sent to the classifier, where unreacted solids settle to the bottom and are separated using a discharge screw mechanism.
The process is carried out to allow enough separation such that the overflow from the classifier to the causticizers contains particles primarily less than 200 microns. The overflow from the slaker classifying section is fed to the causticizers.
The purpose of the causticizers is to provide enough time to allow the causticizing reaction to complete to the extent required. This timing will change according to the type of equipment used for white liquor clarification. Utilizing multiple well-mixed tanks reduces short-circuiting and helps to ensure completion of reaction.
