METHOD FOR THE CAUSTICIZING PROCESS FOR PRODUCING WHITE LIQUOR

摘要

The method is for preparation of white liquor in a chemical recovery process of the kraft process. The green liquor separation process and the white liquor separation process are taking place in the same common filter apparatus with no dedicated green liquor separation apparatus or any dedicated white liquor separation apparatus. The white liquor separation process and the green liquor separation process are conducted in sequence in the same filter apparatus. The white liquor separation process has a part of the cycle time in the range 20-50% of the total cycle time in the same filter apparatus.

主权项

1. A method for preparation of white liquor in a chemical recovery process of the kraft process, comprising:
raw green liquor is first fed to a green liquor separation process wherein dregs are separated out and a clear green liquor is obtained, thereafter adding burnt lime to the clear green liquor in a slaker, followed by a causticizing train with a number of causticizing vessels wherein the causticizing process is finished producing a causticized liquor, thereafter sending the causticized liquor to a white liquor separation process wherein lime mud is separated out and a clear white liquor is obtained to be used as cooking liquor in the kraft process either in form of the clear white liquor or as modified by polysulfide modification in a polysulfide process, and wherein the separated lime mud is sent to a lime mud washing and drying process before feeding the washed and dried lime mud to a lime kiln, the green liquor separation process and the white liquor separation process taking place in the same common filter apparatus with no dedicated green liquor separation apparatus or any dedicated white liquor separation apparatus, and where the white liquor separation process and the green liquor separation process are conducted in sequence in the same filter apparatus and where the white liquor separation process has a part of the cycle time in the range 20-50% of the total cycle time in the same filter apparatus.