Potassium is the 19th element on the periodic table and is represented with the chemical symbol K. Purified potassium is a silver metal that reacts violently with water. Potassium is found in many natural sources as a component of ionic salts (commonly referred to as potassium salts). The main source of potassium production comes from potash. This term is used for any salt that contains the water soluble form of potassium. The most common of these salts is potassium chloride. This potash must be processed to extract the pure potassium.
How is potassium purified?
There are at least 3 methods for separating the pure potassium from potassium salts.
This is one of the most common ways to purify potassium. Sir Humphry Davy invented electrolysis in 1807 and his first discovery was potassium. Basically, electrolysis uses an electric current to force a chemical reaction and is primarily used to separate elements from their compounds. This process has been used on an industrial scale since the 1920′s.
Thermal purification utilizes heat to isolate the potassium. In this process, potassium is purified by creating a reaction between metallic sodium and molten potassium chloride at 850°C. This results in sodium chloride and pure potassium and is called a chemical equilibrium reaction.
Vacuum isolation works by forcing the evaporation of the liquids with the lowest boiling temperatures (called volatile liquids) in a mixture. It can be used to produce very high purity potassium, but it is very rarely used in commercial potassium production.