Chapter 5 - The Uses of Sodium Sulfate

Abstract

This chapter focuses on the application of sodium sulfate. Sodium sulfate is known as an industrial chemical that is often called “salt cake” based upon its former “synthetic” source of reacting salt with sulfuric acid. It has a large number of uses, but as has happened before, this usage pattern has changed dramatically since the early to mid-1970s. Sodium sulfate is used as a filler or substrate in many powdered, granular, or solid detergent formulations. In North America (Canada, the United States, and Mexico), the average box of laundry detergent in the 1990s contained 20-25% sodium sulfate, and some formulas contained up to 50%. Sodium sulfate is an excellent diluent and standardizing material, providing good flow properties and slightly enhancing the detergent efficiency by stabilizing the colloidal properties of the removed dirt or soil. The major use of sodium sulfate in this application depends upon the “big box” powdered detergent market, and this form of cleaning agent sales has many competitors. Sodium sulfate is used in many applications for the dyeing of textiles. A number of other chemicals are made from sodium sulfate—such as sodium sulfide (Na2S).