Green liquor is created when smelt from the recovery boiler is mixed with weak wash in the dissolving tank. Any un-dissolved particulate material in the green liquor is termed "dregs". The failure to remove these foreign materials from the green liquor can lead to many difficulties in downstream lime mud washing. This module describes the composition of dregs, the need for washing of dregs, and identifies and describes the typical equipment used for washing dregs.
•Describe the composition of dregs
•Identify the sources of dregs
•Describe how dregs are washed using a drum filter
•Describe the negative impacts of dregs in the recausticizing process
•Describe the need for washing of dregs
•Describe how dregs are commonly washed and dewatered
•Identify and describe the typical equipment used for washing dregs
•Identify and describe the typical process flows in the dregs system
•Identify and describe the safety hazards associated with the dregs system
