Chemical Makeup

• Baking soda is the common term for sodium bicarbonate (NaHCO3.) Sodium bicarbonate is classified as an acidic salt, as it is derived by mixing an acid with a base. While sodium bicarbonate is a naturally-occurring substance, the pure form is not commonly found in useful amounts in nature. As a result, it did not come into common usage until the late 1840s, when it began to be manufactured under laboratory conditions.
  
  

Soda Ash

• Soda ash is the chemical compound from which baking powder is derived. It was first manufactured in 1789 by French chemist Nicolas Leblanc by combining salt and sulfuric acid. Pure soda ash consists of the compound Na2CO3, from which sodium bicarbonate crystals can be purified. Soda ash is a useful industrial compound in its own right, and is widely used in the manufacture and polishing of glass.
  
  

Trona

• While a great deal of soda ash is still synthesized in laboratory conditions, it is also readily refined from the naturally occurring mineral trona. It is a dense, glassy crystal which is the occasional byproduct of freshwater lake evaporation. Most of the world's trona is produced by a single vast deposit in Wyoming's Green River area. Trona is relatively rare as a sodium-bearing soluble mineral, and the Green River deposit is heavily exploited for the production of soda ash.
  
  

Refining Baking Soda

• In order to derive baking soda from soda ash, a series of steps must be followed. Soda ash is mixed with sodium bicarbonate and water and then put through centrifugal separation to remove impurities. The resulting precipitate is introduced to high-pressure carbon dioxide, which causes the formation of pure sodium bicarbonate crystals. These are separated from the solution by filtration and further centrifugal separation. The crystals represent the familiar form of baking soda.