According to Aqueous Solutions Aps, K2SO4 is soluble in water at different temperatures. Potassium sulfate (K2SO4) is, however, salted out when mixed with water and other solvents, which means an excess of salt precipitates and solubility decreases.
Ammonia has a very strong salting out effect when mixed with K2SO4 that is stronger than water. K2SO4 is also known as arcanite, sulfate of potash and potash of sulfur and is also non-flammable and principally used in fertilizers. It can also be used in glass manufacturing, as a flash reducer in artillery propellant charges. Arcanite is potassium sulfate's mineral form and is relatively rare.