Date of Award


Degree Name

Bachelor of Science


Paper Science and Engineering


The effects of cationic valence were tested against final pulp brightness in the wash deinking process on newsprint. The electrolytes used were AlCl3,CaCl2 and NaCl. The concentrations were varied from 8.32 x 10-4 M to 100 times that amount on all three electrolytes. The effects were studied on the wash water and the cooking liquor seperately, using deionized water as a control run. It was found that there was a noticeable loss of brightness even at the lowest level of electrolyte addition in both the wash water trials and the cooking liquor trials. The effect was greatest when the electrolytes were added to the cooking liquor for AlCl3 and CaCl2. It was also noticed that the addition of Al and Ca ions to cooks containing sodium silicate as a dispersing agent caused a precipate to form, possibly lowering the effectiveness of the dispersing agent.