The invention relates to a process for treating bleaching liquors from pulping
processes based on organic acids. The process is characterized in that inorganic
acid, such as nitric acid, phosphoric acid and/or sulphuric acid, is added into
a bleaching liquor obtained from the bleaching or a stage closely associated with
bleaching, whereby organic acids contained in the bleaching liquor are released
into the bleaching liquor. The organic acids are then separated from the bleaching
liquor and recycled to the cooking stage to be used as cooking chemicals. The nitrogen-,
phosphor- and/or sulphur-containing product thereby produced, from which organic
acids have been separated, is recovered to be used as a fertilizer or as raw material
for a fertilizer.
