Kenya, soda lakes

Sodium carbonate bearing deposits and brines exist around die world. Locations are known in die United States, China, Turkey, Bolivia, Brazil, Venezuela, Mexico, India, Pakistan, USSR, Kenya, Australia, and Botswana (14—20). The overwhelming majority of natural ash production comes from die Green River Basin in southwestern Wyoming. Significant amounts are also produced at Searles Lake in California lesser amounts at Lake Magadi in Kenya. Minor quantities are reportedly produced in Pakistan, die USSR, and China and small amounts of impure trona come from Owens Lake, California. A plant is currently under construction to recover soda ash from brine at Sua Pan, Botswana. Each deposit has its own distinctive characteristics and each requires different processing techniques. 

Manufacture. Sodium carbonate is an important product of the alkali industry. It is obtained naturally by the purification of sal soda which is found in the water of lakes Magadi of Kenya in East Africa, Owens of California in the USA etc. Industrially it is obtained by the Solvay process (ammonia-soda process) sodium chloride solution is saturated by ammonia which is forced into the solution. Carbon dioxide gas is then blown into the solution to form the bicarbonate (NaHCO 3) and ammonium chloride (NH<,.C1). When the bicarbonate is separated and heated, water and carbon dioxide are driven off and sodium carbonate is obtained. The ammonium chloride is mixed with milk of lime and distilled to form calcium chloride and ammonia solution. The recovered ammonia is used repeatedly. 

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