Potassium in Our Time

Feldspar is not important for production of potassium compounds but chloride minerals are Camallite KCl MgClj-bHjO and sylvite (sylvine) KCl. In fact sylvite is the principal ore of potassium compounds. At the beginning of the 20 century the German deposits in Stassfurt, 30 km south of Magdeburg, dominated the extraction of potassium and magnesium salts. Also Wieliczka, 10 km south of Krakow in Poland, has famous salt mines. As the air mixed with salt is considered to be healthy, a sanatorium has been established at the 200-meter level. 

As a mineral, potassium nitrate forms crusts on the surfaces of rocks and stone walls, and occurs as a component of surface soil in Spain, Iran, Egypt and India. In the US it occurs in loose soil in the Hmestone caves of Kentucky, Tennessee and the Mississippi Valley. 

Potassium compounds are among the most important base chemicals, especially potassium hydroxide (caustic potash) KOH, potassium nitrate (saltpeter) KNO3, potassium carbonate (potash) K2CO3, potassium chloride KCl, potassium chlorate KCIO3, potassium bromide KBr, potassium iodide Kl, potassium cyanide KCN, potassium sulfate KjSO, and potassium dichromate Ci 20j. 

As potassium is an essential element for plants its salts are valuable in fertihzers. Potassium chloride obtained from the sylvite deposits and the coimected flotation process can be used directly for this purpose. Potatoes, which are sensitive to chlorides, are instead fertiHzed with potassium sulfate. As a rule, however, fertihzers are mixtures of components containing the elements nitrogen (N), phosphorus (P) and potassium (K). An NPK product thus adds aU three valuable elements to the soiL 

Potassium carbonate, the component in the old potash, is stiU used for the production of high-quahty glass. Potassium chlorate is used in match-heads. Saltpeter was once used in gunpowder and is now found in explosives, fireworks and matches. 

---