Muriate of Potash potassium chloride (KCl), a refined red or greyish red, cubic, crystalline compound that closely resembles common salt (sodium chloride). For agricultural use potassium chloride is often called Muriate of Potash. The name ‘Muriate’ is derived from the term muriatic acid, which is a common name for hydrochloric acid. Over 90 percent of all processed potassium (K) is consumed as fertilizer and at least 78 percent of the K-salts consumed worldwide is Muriate of Potash. It may contain 48 to 62.5% K20 (39 to 61% K), and about 47% chlorine.