Aplication and the role of permanganate as a new bleaching agent

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Permanganate was examined as a new bleaching reagent for chemical pulp and some interesting results were obtained.Bleaching of hardwood KP and OKP with perman-ganate resulted in a greater reduction in K value. Viscosity were also decreased by permanganate bleaching with increasing the charge of permanganate. As employing neutral condition in permanganate bleaching, the drop in viscosity was improved, resulted in higher K value. Comparing at the same K value, neutral condition in permanganate bleaching gave the pulps with higher strength properties than acidic condition. KP gave higher quality pulps after permanganate bleaching than Okp. From this result, oxygen prebleaching stage found to be necessary for permanganate bleaching. In any case, permanganate bleaching gave the pulp with superiorproperties to pulp bleached with ozone.In neutral condition, bleached pulp with per-manganate required to treat with reductant in acidic medium. This post treatment was carried out sufficiently with oxalic acid which playd the role as a acid and a reductant.Brightness of permanganate bleached pulp wereeasily increased with ozone bleaching. The result indicates that not only elementary chlorine but chlorine compounds could be eliminated from bleaching sequence.