Isolation procedures that are used to extract rubidium from mineral ores most often use the ore lepidolite as this ore has the highest concentration of rubidium, (approximately 1.5%), out of all the rubidium ores. Rubidium can also be isolated from potassium minerals and potassium chlorides that contain rubidium. The metal form of rubidium is isolated by reducing rubidium chloride with calcium.
Rubidium chloride can also be reduced with metallic sodium. This isolation process of rubidium requires an electrolytic step because rubidium has poor electronegative properties. In the electrolytic step, the cathode rubidium is reacted with the anode chloride; hot molten rubidium chloride can only be reacted with pure metallic sodium. If the sodium is in the form of a salt, the rubidium chloride cannot be isolated as it will be too soluble in this process. The reaction between sodium and rubidium chloride results in pure rubidium and sodium chloride compounds.
