TAPPI T 619 CM

Abstract

<strong>Scope and significance</strong> <br>The principal use of salt cake in the pulp and paper industry is in the manufacture of sulfate pulp. Salt cake is an anhydrous sodium sulfate which contains varying amounts of impurities. The principal impurities usually are sulfuric acid, common salt, and sulfates of Fe, Al, Ca, and Mg. "Chrome salt cake," obtained as a by-product in making chromic acid, has a yellow color and contains Na₂Cr₂O₇ (and/or Na₂CrO₄) <br>A complete analysis of salt cake is somewhat complicated and involves a considerable number of determinations, as outlined below. Since some mills are mainly interested in the acidity and the Na₂SO₄ content, directions for a "short analysis" are also given. <br>This method is based on wet chemical analyses of the parameters of interest. If available, other techniques such as AA, ICP or ion chromatography may be employed.