Firess - A New Approach to Causticizing, 1998 International Chemical Recovery Conference Proceedings
FIRESS (Ferrite, impurity Removal, Split Sulphidity) provides a means of enhancing removal of non-process elements from the kraft chemical circuit while improving pulp mill thermal efficiency and preparing split sulphidity liquors.
The process involves concentration of the green liquor to permit sodium carbonate crystallization. The sodium carbonate is converted to high concentration, high causticity, sulphur free white liquor by the ferrite (Lowig) process. The residual green liquor is treated with a small quantity of lime to remove non-process elements to a solid effluent and to produce the high sulphidity liquor.
FIRESS achieves its purpose by combining established process steps in a novel way and can be implemented in an existing mill with only minor equipment changes.
Firess - A New Approach to Causticizing, 1998 International Chemical Recovery Conference Proceedings