History Of Sodium Bicarbonate

Sodium bicarbonate, comes from soda ash obtained either through the Solvay process or from trona ore, a hard, crystalline material. Trona dates back 50 million years, to when the land surrounding Green River, Wyoming, was covered by a 600 sq mi (1,554 sq km) lake. As it evaporated over time, this lake left a 200-billion-ton deposit of puretrona between layers of sandstone and shale. The deposit at the Green River Basin is large enough to meet the entire world's needs for soda ash and sodium bicarbonate for thousands of years.

In the late 1800s, another method of producing soda ash was devised by Ernest Solvay, a Belgian chemical engineer. The Solvay method was soon adapted in the United States, where it replaced the Leblanc process. In the Solvay process, carbon dioxide and ammonia are passed into a concentrated solution of sodium chloride. Crude sodium bicarbonate precipitates out and is heated to form soda ash, which is then further treated and refined to form sodium bicarbonate of United States Pharmacopoeia (U.S.P.) purity.

Named after Nicolas Leblanc, the French chemist who invented it, the Leblanc process was the earliest means of manufacturing soda ash (Na2C03), from which sodium bicarbonate is made. Sodium chloride (table salt) was heated with sulfuric acid, producing sodium sulfate and hydrochloric acid. The sodium sulfate was then heated with coal and limestone to form sodium carbonate, or soda ash.

Although this method of producing sodium bicarbonate ash is widely used, it is also problematic because the chemicals used in the process are pollutants and cause disposal problems. An alternative is to refine soda ash from tronaore, a natural deposit.