Which Element Is Used as a Flame Retardant and Why?

Are you confused by the complex chemistry of flame retardants? Choosing the wrong one can lead to safety failures and regulatory headaches, but the underlying science is often simpler than you think.

While elements like phosphorus and bromine are used, aluminum is a key element in one of the most common flame retardants. It is used in the compound aluminum hydroxide (ATH) because it safely suppresses fire by releasing water.

As a producer of aluminum hydroxide here in Henan, I work with this element every day. We don’t sell pure aluminum, of course. We sell a specific, stable compound that has a remarkable ability to stop fire. This isn’t based on complex, toxic chemistry but on a simple, physical reaction.

Let’s look at the different chemicals and elements that are used to make products safer from fire. Understanding the options will help you see why compounds based on the element aluminum are a leading choice for so many industries.

What chemical is used for fire retardant?

It can be difficult to navigate the market with so many different chemical flame retardants available. It’s hard to know which options are effective, safe for consumers, and compliant with modern environmental regulations.

The most common halogen-free chemical is aluminum hydroxide (ATH). Other chemicals include magnesium hydroxide (MDH) and various phosphorus-based compounds. Older, halogenated chemicals containing bromine or chlorine are being phased out due to toxicity concerns.

The world of fire retardants has changed a lot. For years, the most effective chemicals were halogenated compounds. They worked very well, but we later learned they released toxic and corrosive smoke during a fire. Today, the focus is on safety and sustainability. For an experienced buyer like Mr. Park, understanding this shift is key to sourcing materials¹ for the modern market.

Here is a simple breakdown of the main chemical families:

From my factory, we focus on producing ATH. It is a clear winner for companies looking for a solution that is effective, cost-efficient, and, most importantly, aligns with global safety standards like RoHS.

What makes a material flame retardant?

It can seem like magic that a simple powder added to plastic can stop it from burning. If you don’t understand how it works, it’s hard to trust that it will properly protect your product and your customers.

A material becomes flame retardant when an additive interferes with the fire triangle of heat, fuel, and oxygen. It can do this physically by cooling the material, or chemically by stopping the combustion reaction in the air.

At its core, stopping a fire is about breaking this cycle. Different flame retardants attack different parts of the triangle. The "best" flame retardants, in my opinion, are the ones that work physically because they do their job without creating harmful byproducts.

Let’s look at how this works.

• Attacking the Heat: Aluminum hydroxide is a master at this. When it gets hot (around 200°C), it starts to decompose. This process is endothermic, meaning it absorbs a huge amount of heat energy. It acts like a built-in air conditioner, keeping the plastic cool and preventing it from igniting.
• Attacking the Fuel and Oxygen: As the ATH decomposes, it releases its water molecules (H₂O) as steam. This harmless steam pushes oxygen away from the fire and dilutes the flammable gases that the plastic is trying to release. No fuel and no oxygen means no fire. The solid part left over, aluminum oxide, forms a protective char barrier.

This physical mechanism is simple and predictable. It’s why so many companies trust ATH to provide reliable fire safety².

What mineral is used as a flame retardant?

You need a flame retardant with a stable supply chain that isn’t dependent on complex chemical synthesis. Sourcing a material derived from a natural mineral offers reliability and often a better environmental profile.

The most widely used mineral flame retardant is aluminum hydroxide, which is refined from bauxite ore. Another common one is magnesium hydroxide, which comes from brucite ore or is extracted from seawater. These are often called mineral hydrates.

Here in Henan province, we are in a major hub for aluminum production. This gives us direct access to our raw material: bauxite. This direct link from the mine to our processing plant is a huge advantage. It allows us to control quality from the very start and maintain a stable, cost-effective supply for our customers.

The process of turning this rock into our fine white powder is called the Bayer Process³. We crush the bauxite and use a caustic soda solution to dissolve the aluminum content. We then filter out the impurities (which are called "red mud") and precipitate out pure, crystalline aluminum hydroxide. This process ensures we get a consistent product with high purity. Using a naturally derived mineral like ATH is a great story for brands who want to show their commitment to using effective and well-understood materials in their products.

What element is fireproof?

You often see the word "fireproof" in marketing. But relying on this absolute term can lead to a false sense of security, as nearly any material will fail under extreme conditions.

No element is truly fireproof. With enough energy, any element can be made to melt, burn, or react. Elements with very high melting points like tungsten and carbon are extremely heat-resistant, but they are not impervious to fire.

This is an important distinction that I always try to explain to customers. We should talk about fire resistance⁴, not being "fireproof." Fire resistance is a measurement of how long a material can withstand a fire under tested conditions.

So, while no element is perfectly fireproof, some are incredibly tough. Tungsten, for example, has the highest melting point of any metal at 3,422°C. But that doesn’t make it practical for use as a general flame retardant. This is where aluminum hydroxide shows its brilliance.

When ATH does its job, it releases water and leaves behind a layer of aluminum oxide (Al₂O₃)⁵. This resulting material is a type of ceramic. And aluminum oxide has an extremely high melting point of over 2,000°C. So, the aluminum hydroxide actively creates a highly fire-resistant ceramic barrier, right on the surface of your product, at the exact moment it’s needed most. It’s a clever way to use the properties of an element’s oxide to protect the material underneath.

Conclusion

Aluminum is a key element in fire retardants, used in the compound aluminum hydroxide. It works by physically and safely releasing water to suppress fire, making it a reliable, effective choice.