K2SO4

Potassium sulfate, with the chemical formula K2SO4, is an inorganic salt consisting of potassium ions and the sulfate anion. In its mineral form it is known as arcanite. It appears as colorless to white, crystalline solid and is stable under ordinary conditions. It is soluble in water and is less hygroscopic than many other potassium salts.

Industrially, potassium sulfate is produced mainly by reacting potassium chloride with sulfuric acid: 2 KCl + H2SO4 → K2SO4 + 2 HCl. It can also be obtained from natural potash deposits and brines or recovered during the processing of potassium-rich minerals. The compound is used in a variety of agricultural and industrial applications, but its primary use is as a fertilizer source of potassium and sulfur, particularly on soils where chloride-bearing fertilizers would be detrimental to crops.

As a fertilizer, potassium sulfate provides potassium (K) and sulfur (S) without introducing chloride ions, which can be harmful to some plant species or soil conditions. It is commonly employed for crops sensitive to chloride or in specialty fertilizers that combine potassium with other nutrients. Beyond agriculture, potassium sulfate has historical uses in the glass and ceramics industries and has been used in certain chemical processes where a soluble potassium source is required.

Safety and handling considerations are generally modest; potassium sulfate is not highly toxic when handled according to standard industrial practices. Routine precautions for chemical fertilizers apply, including avoiding inhalation of dust and excessive ingestion. Excessive application can contribute to soil salinity and imbalances in soil nutrient levels, so application rates are typically managed according to crop needs and soil tests.