Abstract
A study has been made of purifying the alkali pulp waste liquor by treatment with chemicals. It has been shown that aluminium sulfate can remove effectively the oxidizable matters with the increase of its concentration. The removal of oxidizable matters can also be achieved without aluminium sulfate by the addition of enough hydrochloric acid as to bring pH of the waste liquor to 4-5 (Fig. 1.). The extent of removal was increased with lowering pH value and raising temperature of the waste liquor (Figs. 3 and 4). In order to estimate the amount of acid required for purification of the waste, the titration curve has been made (Fig. 2). The determination has also been made of the change in color intensity during the titration with hydrochloric acid (Fig 5).
