Introduction
Cerium (atomic number 58) is the most abundant of all rare earth elements, found in the Earth’s crust at concentrations similar to copper. It is a Light Rare Earth Element (LREE) and is often the “surplus” element in mining operations because it is produced in high volumes alongside more valuable magnetic elements.
Chemical & Physical Properties
A grey, malleable metal that easily oxidizes in air. Cerium is unique among lanthanides because it can easily switch between two oxidation states (+3 and +4), a property that makes it highly effective as a catalyst and an oxygen storage medium.
Occurrence & Production
Cerium is the primary constituent of both bastnäsite and monazite minerals. Due to its abundance, it is usually the cheapest and most widely available rare earth element.
Key Applications & Uses
- Catalytic Converters: The single largest use of cerium is in automotive catalytic converters, where it helps reduce emissions from internal combustion engines by storing and releasing oxygen to burn off pollutants.
- Polishing Agents: Cerium oxide is the premier industrial polishing powder used for finishing optical glass, mirrors, silicon wafers for semiconductors, and screens.
- Glass Additive: Used to decolorize glass by counteracting iron impurities, and conversely, to give glass a yellow color for UV protection in eyewear.
- Mischmetal: A major component of the flint alloy used in cigarette lighters.
Future Outlook & Significance
Because it is overproduced relative to demand compared to its rarer cousins like Neodymium, finding new, high-volume uses for Cerium is a major focus of materials science research to balance the economics of rare earth mining.