Patent ID: 7371307
Filing Date: 2008-05-13
Classification: D21C

Abstract:
1. A method of producing an oxidized white liquor containing polysulphide comprising: i) oxidizing a white liquor with oxygen containing gas in the presence of lime mud, manganese dioxide or both to produce on oxidized white liquor containing polysulphide and having a first active polysulphide concentration measured at 285 or 286 nm (PS ii) storing said oxidized white liquor at a temperature of 50° C. to 90° C. for a time of 6 to 72 hours while monitoring the concentration of active polysulphide spectrometrically and the concentration of total polysulphide gravimetrically to produce an oxidized white liquor having a second active polysulphide concentration measured at 285 or 286 nm (PS