Minerals Information
Byproduct sodium sulfate recovery has been derived from the primary production of ascorbic acid, cellulose, flue gas desulfurization, hydrochloric acid, lithium carbonate, rayon, resorcinol, silica, and sodium dichromate manufacture. Virtually all the locations are in the Midwest, South, and the East. Sodium sulfate has been recovered as a waste product from these manufacturing processes and has competed with sodium sulfate produced from natural sources.
Historically, sodium sulfate has been used in pulp and paper, detergents, glass, textiles, and several other miscellaneous end uses. Imports, primarily from Canada, tended to be greater than exports.
Because synthetic sodium sulfate was a byproduct and considered a waste product, it was sold at any price to dispose of it. The smaller natural sodium sulfate industry, which was concentrated more in the West, based its price around the market price of synthetic sodium sulfate.
Sodium sulfate was mainly used in the Kraft pulping process throughout the 1960's and 1970's. However, around 1986, the trend reversed, with soap and detergents becoming the primary end use. In this sector, sodium sulfate was used as a filler in powdered home laundry detergents because of its whiteness. However, in the late 1980's, liquid detergents and superconcentrates, which do not use sodium sulfate in their formulation, became the preferred choices of laundry detergents. The pulp and paper industry strived to recycle as much sodium sulfate as it could and prevent any discharges to the environment from waste water effluent.
By 1990, the U.S. sodium sulfate industry had excess capacity to supply a declining domestic market. Several companies that recovered sodium sulfate considered modifying their technology to produce nonsodium sulfate byproducts that may have more market potential. U.S. sodium sulfate exports have increased to supply material to foreign textile and detergent industries that still manufacture powdered detergents.