Extracted rare earth elements. Leaching rare earth with ammonium sulfate refers to extracting rare earth elements from ion-adsorbed ore with ammonium sulfate solution. These rare earth elements exist in the form of ions in the ore adsorbed with ions, and ammonium sulfate solution can separate these ions from the ore. Ammonium sulfate extraction is a common method to extract and enrich rare earth elements, which is widely used in metallurgy, chemical industry, electronics, optics and other fields. Because of its special physical and chemical properties, it is called "industrial vitamin".