Natural sodium sulphate deposits are found in several alkaline lakes with constrained drainage in the southern part of Saskatchewan. In its natural form it is commonly called Glauber's salt or mirabilite. Sodium sulphate can also be produced artificially through several chemical processes. Currently about 50% of sodium sulphate is artificially produced in the world. Saskatchewan is a world leader in naturally produced sodium sulphate, currently producing 6% of the total world supply. The four major companies extracting sodium sulphate in the province are Goldcorp Inc., Millar Western Industries, Ormiston Mining and Smelting Co. Ltd., and SOTEC Products Ltd. All production of sodium sulphate in Saskatchewan is in the natural form thanks to the abundance of alkaline lakes. There are presently 21 major sodium sulphate deposits, with more than 500,000 tonnes of sodium sulphate mineral deposits in each. During the production stage several techniques may be used to extract the product, depending on the nature of the deposit. Common practices include dredging and solution mining or pumping brine into evaporation ponds, where natural evaporation concentrates the minerals and crystallization occurs. The sodium sulphate crystals are then extracted from the mixture.
In Saskatchewan there are two grades of sodium sulphate: the first is a salt cake grade, which is primarily used for wood digestion in the pulp and paper industry; the second is a detergent grade product that is used in detergents, glass, dyes, textiles, tanning, and in the chemical industry. Saskatchewan has five operating sodium sulphate facilities where the annual productive capacity is 530,000 tonnes. The consumption rate of sodium sulphate is falling owing to environmental concerns, especially in North America. The industry, however, is attempting to be proactive with these concerns by creating an alternate use for sodium sulphate. There has been research done to use the product as a pollution control agent at coal-fired plants; the sodium sulphate would be added to the coal to improve its efficiency and reduce the waste released into the environment. The decline of its use in North America is being offset by the expanding markets in Asia and Eastern Europe: both regions are developing in the areas of textiles, glass and detergents, and therefore represent a high demand for sodium sulphate. In Saskatchewan, research and development work is being carried out to create value-added products with sodium sulphate, which can now be used in the manufacturing process of certain fertilizers, soda ash, sodium bicarbonate, and caustic soda.
Julie L. Parchewski