Cerium Uses: The Applications That Actually Drive Demand

Cerium (Ce) is one of the most widely used rare earths, mainly because it is relatively abundant and because cerium oxide (CeO₂), often called "ceria," is extremely useful in industry. In practice, most high-volume uses are not "cerium metal" use cases - they are ceria and other cerium compounds.

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Glass polishing and precision polishing (a core use)

The single most recognizable industrial use of cerium is glass polishing, where ceria is used as a polishing agent to produce high-quality finishes on:

• optical glass (lenses and precision optics)
• architectural and automotive glass
• specialty glass products that need tight surface tolerances

Ceria also shows up in chemical-mechanical polishing (CMP) and related planarization steps used for advanced manufacturing, where ceria slurries can polish silica-based surfaces effectively.

Learn more: To understand how this demand connects to sourcing and processing, see Cerium supply chain and Cerium mining and processing.

Automotive catalytic converters (ceria as an oxygen buffer)

Cerium is heavily associated with automotive catalytic converters, where ceria is used because it can store and release oxygen via reversible cerium redox chemistry. That oxygen "buffering" helps catalysts perform under real driving conditions when exhaust composition is changing.

This matters because it is a true "industrial backbone" application. It is also one reason cerium is regularly listed among minerals tied to catalytic converters.

To go deeper on where catalyst-grade material comes from and how it moves through the market, use Cerium supply chain.

Glass additives: decolorizing and UV control

Cerium compounds are used as glass additives, not just for polishing finished glass.

Two practical roles are common in the literature and industry discussion:

Decolorizing

Cerium can help reduce unwanted tint by influencing the oxidation state of iron impurities in glass, which affects color.

UV absorption

Cerium-containing glass can be engineered to absorb ultraviolet light with minimal visible coloration, useful in protective and specialty glass applications.

These "in-the-melt" uses are part of why the glass industry is frequently mentioned as a major end user of rare earth raw materials, including cerium-based materials.

Ceramics and specialty materials

Cerium is also used in ceramics and related materials applications. Depending on the product, cerium compounds can support color, stability, or other functional properties. This is one of the standard end-use buckets cited for cerium alongside polishing and catalysts.

For the "where does the ceramic-grade material come from" angle, see Cerium mining and processing.

Metallurgy: alloying, deoxidation, and desulfurization

Cerium has several metallurgy-related use cases, including roles as an additive in certain alloys and as a chemical helper in melts.

A well-discussed function is using cerium or ceria-related additions to help remove oxygen and sulfur from molten metal systems (and to influence inclusion behavior).

This "metallurgy" category is also repeatedly listed as a practical end-use bucket for cerium in official and reference material summaries.

Fire-starting alloys (the famous one people recognize)

Cerium's pyrophoric behavior is the reason it is associated with lighter flints, typically via cerium-rich alloy mixtures (often discussed under "mischmetal" and ferrocerium-type products).

This is not necessarily the biggest demand driver compared with polishing or catalysts, but it is one of the most widely recognized everyday applications.

Energy and advanced chemistry (smaller, but real)

Ceria shows up in a range of advanced chemical and energy material contexts, largely because it is chemically flexible and stable.

Examples discussed in the technical literature include:

• ceria-based catalytic chemistry beyond automotive catalysts
• solid oxide fuel cell (SOFC) related materials, where ceria-based materials can be used due to their ionic conduction properties

These are best treated as "important but not always high-volume," depending on the specific market and product.

Where cerium demand comes from (and why it can change)

Cerium demand is tied to a handful of real industrial systems:

• glass manufacturing and finishing (polishing and additives)
• emissions control catalysts, especially automotive
• broad ceramics and metallurgy categories

Demand can shift when:

→ polishing processes change (different abrasives, different surfaces, different reuse patterns)
→ emissions-control technology changes
→ substitution becomes economical in specific applications

Cerium Uses FAQ

What is cerium used for most?

In most practical discussions, the biggest recurring uses are glass polishing, glass additives, and automotive catalytic converters, with additional use in ceramics and metallurgy.

Is cerium mainly used as a metal?

Often, no. Many major applications rely on cerium compounds, especially cerium oxide (ceria).

Why is cerium used in catalytic converters?

Because ceria can help manage oxygen availability in the catalyst system through reversible redox behavior, supporting converter performance under changing exhaust conditions.

Why is cerium used to polish glass?

Ceria is widely used because it can produce high-quality polished surfaces on glass and silica-based materials and is established in both traditional glass polishing and CMP-type applications.