History Discovery of sodium and magnesium sulphate salts resulted from a search for potash in the alkali lakes. Because of the potash shortage during World War I, many of these lakes were claim staked in 1918. Most of the claim holders allowed their claims to lapse when no potash was found. A few had discovered substantial deposits of Epsom and Glauber's salts. In Saskatchewan, there are 21 major sodium sulphate deposits with more than 500,000 tonnes of reserves each. Since the first attempt at sodium sulphate mining in Saskatchewan in 1918-19, more than 20 companies have been involved in development work over the past 70 years. Description of Sodium Sulphate Sodium sulphate in its natural form is also known as Glauber's salt or mirabilite. (Na2SO4 10H2O). In the processed form, the combined water is absent and only the salt is left (Na2SO4). The natural material contains 55.9 per cent water. Deposits are formed by the natural evaporative concentration of dissolved salts entering isolated drainage basins by leaching of the surrounding terrain and via brine springs. Location Natural sodium sulphate deposits occur in numerous alkaline lakes with restricted drainage in southern Saskatchewan. The solutes can enter the lake through the leaching effects of surface and near-surface water in the surrounding terrain and via inflowing brackish and brine springs. The Quill Lakes are examples of sodium sulphate deposits that remain as brine. The principal impurities in slat beds are clays, silt, sand and organic matter. Mining Sodium sulphate is produced from natural brines and crystal deposits in alkaline lakes, or as a by-product of various chemical processes. Depending on the nature of the deposit and the specific company, the production technique may be dredging and solution mining of a permanent crystal bed of mirabilite (Na2SO4 10H2O), or by pumping brine into evaporation ponds where natural evaporation concentrates the dissolved salts. When the ponded solution cools in the autumn, differential crystallization occurs. Sodium sulphate crystals are the first to drop out. The remaining brine containing sodium chloride and magnesium sulphate is returned to the lake. At present, world production of sodium sulphate is split about 50:50 between natural and by-product production. All Saskatchewan production is natural product from alkaline lakes. Producers of Sodium Sulphate The amount of sodium sulphate mined in Saskatchewan has risen over the years. There are five sodium sulphate facilities in the province owned by four separate companies. The annual productive capacity of the Saskatchewan industry is about 530,000 tonnes. One of the producers is converting to the production of much higher value sodium bicarbonate. Saskatchewan Sodium Sulphate Producers Company Plant Deposit Goldcorp Inc Division: Saskatchewan Minerals Division Production of Sodium Sulphate Chaplin Lake Chaplin Goldcorp Inc Division: Saskatchewan Minerals Division Production of Sodium Sulphate Fox Valley Ingebright Lake Millar Western Industries Sodium Sulphate & Magnesium Sulphate Palo Whitehorse Lake Ormiston Mining and Smelting Co. Ltd. Ormiston Horseshoe Lake SOTEC Products Ltd. Mining Sodium Sulphate. Cabri Snakehole Lake Uses for Sodium Sulphate Saskatchewan produces two grade of sodium sulphate. Salt cake - This substance contains at least 97 per cent Na2SO4 and is used chiefly in wood digestion reagents in the pulp and paper industry. Detergent grade - This sodium sulphate had up to 99.77 per cent Na2SO4 and is used for detergents, glass, dyes, textiles, tanning and in the chemical industry. Economic Impact for Saskatchewan Saskatchewan is one of the world leaders in natural sodium sulphate production and currently produces six per cent of the total (considering both natural and by-product sources). The consumption of sodium sulphate in the pulp and paper industry in North America is declining for environmental reasons. However, to some extent the lower consumption in North America is offset by growth in Asia and parts of Eastern Europe. In both of these regions, the consumer market is just starting to develop and additional sodium sulphate will be needed to produce glass, textiles and detergents. Expansion of detergent use in developing countries is having a positive effect on sodium sulphate markets. The Saskatchewan sodium sulphate industry is trying to offset the decline in North American demand by successfully developing advanced technologies to produce new, value-added products. Research has developed new processes using sodium sulphate to manufacture potassium and ammonium sulphate fertilizers, soda ash, sodium bicarbonate and caustic soda with ammonium sulphate as a by-product. Natural sources are expected to experience significant competition from synthetic product in the battery reclamation industry. Current technology can purify the by-product to the food grade level. This is expected to have a major impact of detergent grade product made from natural sources. Environmental Concerns While there are environmental concerns with sodium sulphates in the detergent industry, a new market for sodium sulphate may develop in pollution control at coal fired plants. It may be added to the coal as a conditioner to improve the efficiency of high-temperature electrostatic precipitators by preventing clogging of fly-ash. About five kilograms of sodium sulphate would be used per tonne of coal.