What are the differences between "high-whiteness aluminum hydroxide" and ordinary aluminum hydroxide in terms of application and price?

Struggling to choose the right aluminum hydroxide? The wrong choice can ruin your product’s appearance and cost you more. Understanding the key differences is simple and will save you money.

High-whiteness aluminum hydroxide is purer, brighter, and used in high-end applications like solid surfaces, so it costs more. Ordinary aluminum hydroxide is for industrial fillers where color isn’t critical, making it cheaper. Whiteness is the main price driver, followed by particle size.

This high-level view is helpful, but the details are where you can really optimize your costs and product quality. As someone who has managed production for years, I know that small details make a big difference. Let’s break down the different types to see where the value truly lies and help you make the best choice for your business.

What are the different types of aluminium hydroxide?

Feeling lost in the jargon of aluminum hydroxide grades? Using the wrong type can lead to production issues and wasted money. Let’s clarify the main types available to you.

Aluminum hydroxide is mainly categorized by its production method: the Bayer process (wet) and the sintering process (dry). It’s also graded by properties like whiteness, purity, and particle size, leading to industrial, standard, and high-whiteness grades for different applications.

In my factory, we primarily use the Bayer process¹ because it gives us better control over purity² and particle size³, which is critical for higher-grade products. The choice of production method is the first step that defines the material’s potential. From there, we refine it to meet specific customer needs.

Grades Based on Purity and Whiteness

The most common way buyers like you will see aluminum hydroxide⁴ categorized is by its grade. This is a simple way to understand its quality and intended use. A small difference in whiteness⁵ or purity can completely change the final product’s look and performance. I’ve seen customers save a little on a lower grade only to have problems with discoloration in their final products later.

Here is a simple breakdown I use to help my clients:

What makes aluminum hydroxide different?

Do you think all white powders are the same? Assuming so can degrade your final product’s quality and performance. Key properties set different grades of aluminum hydroxide apart.

The key differences are whiteness, particle size, purity, and oil absorption. Whiteness affects appearance, particle size impacts processing and strength, purity influences chemical resistance, and oil absorption is crucial for use in polymers and resins. These factors determine its suitability and price.

These properties are not just numbers on a data sheet; they directly affect how the material behaves in your production line and in your final product. Over the years, I’ve learned that understanding these four pillars is the secret to selecting the most cost-effective material without sacrificing quality. It’s the difference between a good product and a great one.

Whiteness: The Price Driver

As I mentioned in my insight, whiteness is the single biggest factor affecting price. High-whiteness grades require purer raw materials and more refined processing to remove trace impurities⁶ like iron oxide, which cause a yellow or gray tint. For applications like white artificial stone countertops, whiteness is non-negotiable.

Particle Size: From Filler to Functional Additive

Particle size, or D50, is the second most important factor. Standard grades might have a particle size of 10-20 microns. But for some applications, you need an ultrafine powder, maybe around 1-3 microns. Finer particles offer a smoother surface finish and better mechanical properties in composites. But grinding the material to be that fine requires a lot of energy and special equipment, so the price goes up.

What levels does aluminum hydroxide lower?

Are you looking for a reliable flame retardant? Choosing the wrong one can cause you to fail safety tests and damage your reputation. Aluminum hydroxide is an effective solution for reducing flammability.

Aluminum hydroxide is a non-toxic flame retardant. When heated, it decomposes and releases water vapor, which absorbs heat and dilutes flammable gases. This process effectively lowers the temperature and slows the spread of fire. It also reduces smoke production.

This is one of the most valuable properties of aluminum hydroxide, especially in industries like wire and cable, construction materials, and transportation. It’s an environmentally friendly choice because it contains no halogens. Instead of releasing toxic gases when it burns, it releases harmless water vapor. It’s a simple, elegant solution to a serious safety problem.

How It Works: A Simple Chemical Reaction

The science is straightforward. The chemical formula is Al(OH)₃. The " (OH)₃" part represents three water molecules bonded to the aluminum. When the material is heated to around 220°C, a process called endothermic decomposition begins. This means the material absorbs a large amount of heat from its surroundings. At the same time, it releases the three water molecules as steam. This steam cools the material and also displaces the oxygen needed for the fire to burn.

The Benefit: Smoke Suppression

Beyond just stopping flames, aluminum hydroxide is also an excellent smoke suppressant. The water vapor it releases dilutes the combustible gases, which means less smoke is formed. In a real fire, smoke is often more dangerous than the fire itself, so this is a critical safety feature. This is why you see it used so often in confined spaces like airplane interiors and subway cables, where clear escape routes are essential.

Is aluminum hydroxide white?

Are you assuming all aluminum hydroxide is perfectly white? This misconception can lead to off-color products and customer complaints. Let’s look at what "white" really means in our industry.

Yes, aluminum hydroxide is a white powder. But its degree of whiteness varies a lot based on its purity and the manufacturing process. "High-whiteness" grades are exceptionally bright, while standard grades can have a slightly off-white or grayish tint due to trace impurities.

In my experience running our production lines, controlling whiteness is a constant focus. Even a tiny amount of contamination can affect the final color. For a buyer like Park Chung-hee, who deals with pharmaceutical applications, purity and color consistency are probably very important. This is why a direct relationship with the source factory is valuable; we can ensure you get the exact specification you need for every single batch.

Measuring "Whiteness"

We don’t just rely on our eyes to judge color. In the industry, we use a device called a colorimeter to measure whiteness objectively. The most common scale is the CIE Lab color space, where the [L value](https://en.wikipedia.org/wiki/Whiteness_(colorimetry))[^7] represents lightness from black (0) to white (100). When we talk about "high-whiteness," we are talking about a product with a very high L* value.

The Role of Impurities

What makes one batch less white than another? The answer is almost always impurities. Tiny amounts of iron oxide (rust) are the most common culprit, giving the powder a yellowish or reddish tint. Sodium salts, if not washed out properly during the Bayer process, can also affect the final appearance. At our plant, we use multi-stage washing and magnetic separation to remove these impurities and achieve the high whiteness our customers demand.

Conclusion

High-whiteness ATH costs more for its purity and appearance, ideal for premium products. Standard grades offer a cost-effective solution for industrial applications where color is less critical.