Studies were carried out on bleaching of bagasse PAP with Hydrogen Peroxide-Alkaline (Pa) solution. The Pa solution was a mixture of water, hydrogen peroxide (0.5-5% on od. PAP), sodium hydroxide (as Na2O 0.5-5% on od. PAP), and small quantities of auxiliaries (DTPA), the liquor ratio of the mixture to PAP being 10 l/kg.
Pa treatment made unbleached pulp (UPAP 81-21, Hunter brightness 51.8% kappa no. 7.2) into higher brightness and slightly lower kappa no. pulps (Hunter brightness 68.9%. kappa no. 4.8). Especially suitable quantity of hydrogen peroxide (H2O2 1-3% on od. PAP) was effective for bleaching. Pa Pa two stage treatment gave semibleached pulp (Hunter brightness 72.0%, kappa no. 4.9) without chlorine. PaH and PaD two stage sequences with small quantities of hypochlorite and chlorine dioxide (as available Cl2 3%, and ClO2 3% on od. PAP respectively) gave high brightness bleached pulps.