Abstract: Disclosed is an improved chlorinated pulp bleaching process and apparatus which reduces caustic requirements significantly, wherein the washed chlorinated pulp, after first separating therefrom the effluent from the chlorination stage washing step, is treated with recycled alkaline extraction stage effluent in an additional washing step between the chlorination stage washing step and the extraction stage washing step; and wherein the effluent from the additional washing step is separated from the twice-washed pulp and, optionally wherein that effluent is recycled as shower water for the chlorination stage washing step, before the twice washed pulp is mixed with the caustic in the extraction stage.

Abstract: A device and method for measuring and controlling the extent of oxidation of kraft white and black liquors and also flue-gas scrubber circulating liquors is provided, comprising two dissimilar metal electrodes whose potential difference on immersion in the kraft liquor is proportional to the sulphide ion concentration and to the concentration of other oxidizable components in the liquor.

Abstract: Lignocellulosic materials such as wood, bagasse, straw, reeds, and other plants and crops can be delignified effectively by a soda-type pulping with an alkaline liquor containing small quantities of both ethylenediamine or like amino compound, and a cyclic keto compound, such as anthraquinone. Pulping rates comparable to kraft are achieved and the pulps thereby obtained have excellent physical properties, especially tear strength.