Patent ID: 8518273

Claim:
A method for cleaning a filter sheet and filter cake in a pressurized white liquor filter, comprising: providing a filter sheet and a filter cake disposed in a pressurized white liquor filter, the filter cake being a part of a lime mud cake being closest to the filter sheet, the filter cake not being removed by a scraper when the scraper scraping the lime mud cake; causticizing green liquor by adding lime thereto to form a lime mud slurry; the white liquor filter filtering white liquor from lime mud particles in the lime mud slurry to form a filtered white liquor, the white liquor filtrate being principally constituted by the white liquor filtered from the white liquor filter; and conveying the filtered white liquor to a container; a pump pumping the filtered white liquor from the container to a spray nozzle, and the spray nozzle spraying the filter sheet and filter cake with the filtered white liquor to clean the filter cake.