Rubidium

Rubidium and cesium are the heaviest alkali metals (Group IA). They are silvery white, soft and react spontaneously with air to form the oxide and violently with water with the release of hydrogen. Rubidium is rare in resource terms but it ranks 16th in crustal abundance, is 5 to 6 times the abundance of the base metals, and is more abundant than such common elements as sulphur, chlorine and carbon but is rarely concentrated to levels of interest for commercial extraction. The principal source of rubidium is in certain highly evolved granite pegmatites. The rubidium typically occurs in potash-feldspars where it substitutes for potassium to levels of typically less than 5%, and in lepidolite from which it is extracted commercially. An extremely rare pure rubidium feldspar known as rubicline has been documented on Avalon's Lilypad Lakes property.

PROPERTIES AND APPLICATIONS OF RUBIDIUM

Rubidium has been available commercially for only forty years, a byproduct of lithium chemcals production. Rubidium is the second most electropositive of all elements after cesium, a measure of its potential for new applications. Limited supply constrains use but discovery of large new resources of rubidium in Avalon's Separation Rapids Rare Metals Pegmatite and a smaller, but higher grade, resource at Avalon's Lilypad Lakes property, may create new supplies leading to expanded commercial applications.

• Biomedical: Rubidium and cesium compounds find use as catalysts in biomedical and chemical research, tag/trace compounds, etc. Cesium Chloride has recently been found to be effective in treating all forms of cancer and shows great potential as an important new cure for this commonly fatal disease.
• Photoelectrics: The low ionization potential of cesium and rubidium is exploited in photoelectric cell design and in photo-emissive and scintillation application in electronics. A cesium vapour-laser computer has been experimentally demonstrated.
• Ceramics: Rubidium feldspar used in high voltage ceramic insulators, where it has been demonstrated that the rubidium greatly increases its insulating capacity leading to reduced current losses on major transmission lines.
• Heavy media: Cesium formate (S.G 2.4) a specialty drilling fluid developed by Cabot Corp is used in drilling deep, high pressure, high-temperature oil wells. Rubidium may have potential in similar applications.
• Specialty glass: Rubidium carbonate glass used in military seeing-eye devices, and possibly useful for anti collision devices for cars. Rubidium and cesium are used in infrared optical devices for night vision glasses.
• Ion Propulsion: Cesium and rubidium ions can be used for ion propulsion systems in space although cesium has the greater potential in this application. Magnetohydrodynamics and vapour engines are technologies that use both metals.
• Specialty Metal Alloys: Rubidium forms interesting amalgams with mercury and alloys with gold, properties which should expand usage.