What Processes Are Rotary Kilns Used For?

When looking for a rotary kiln for sale, it’s important to understand what your new kiln could do for you.  In a broad sense, a kiln is intended to bring about chemical or physical changes through heat, but that function can be broken up into several discrete possible processes.

In this article, we’ll briefly outline each of the roles a rotary kiln can serve.

The Six Main Processes A Kiln Can Accomplish

Calcination

Calcination is the process of heating a material to a point that chemical separation occurs, such as when creating inorganic materials.  For example, calcium carbonate can be heated to create calcium oxide + carbon dioxide.  This same process can also be used to remove bound moisture from a substance.

Organic Combustion

Kilns are also extremely effective at burning organic waste out of a material or product, leaving behind nothing but ash.  For example, rotary kilns are frequently deployed in waste treatment plants to reduce the volume to materials needed to be processed.

Thermal Desorption

Thermal desorption is another alternative for removing organic materials from other materials, but by merely causing separation rather than outright combustion.  This is useful when there’s a concern about combustion causing the release of harmful byproducts into the atmosphere, or about the material in question becoming volatile if ignited.

Sintering

Sintering is the process of heating up a material to just below its melting point, thus increasing the internal strength of the product.  This is common in many forms of metalwork.

Heat Setting

Heat setting is useful when you need to bind two materials together which normally would be difficult to bond, particularly if one is more heat-resistant than the other.  Heat-setting processes are used in creating Teflon coatings, for example.  It’s also an excellent way to permanently bond paints and other colorings onto various materials.

Reduction Roasting

Finally, a rotary kiln can be utilized to remove oxygen from materials, such as ores, through the introduction of carbon monoxide into the environment.  This encourages them to bind together and be released from the material

The Kiln in Cement Production

Cement is a ubiquitous binder, and starts its life as limestone. This calcium-rich rock enters the rotary kiln, where it’s cooked in scorching temperatures exceeding 1,400°C. The intense heat triggers a chemical dance, decomposing the limestone into calcium oxide, the main ingredient of cement clinker. Think of clinker as the “pre-cooked” version of cement, a hard, nodular material ready for grinding and mixing with other components. Without the kiln’s heat, this essential building block wouldn’t exist.

Beyond heat, the kiln’s rotating is important to the process. The constant tumbling ensures even exposure of the raw materials to the inferno, promoting uniform clinker formation. It’s a delicate balance of temperature and movement, a testament to the kiln’s engineering prowess. This is also why rotary kiln services are so important to keep the kiln maintained and operating.

Forging Iron and Steel: The Kiln in Metalworking

In the metallurgical industry, kilns are used in the production of iron and steel. Here, the focus shifts from limestone to iron ore, a mineral rich in iron oxides.

The key to this process is called sintering. This process sees the iron ore crushed, mixed with additives, and then heated in the kiln to around 1,300°C. The intense heat melts and binds the iron oxides, creating a strong, porous material called sinter. This sinter, unlike the clinker in cement, isn’t the final product. It’s a precursor to molten iron, the foundation for steel production.

We Have a Wide Inventory of Kilns on Sale to Suit All Your High-Tech Heating Needs

Kiln Technology Company Company has over twenty years’ experience in buying, selling, and servicing kilns across Texas, and across the country.  We offer highly competitive rates and industry-leading warranty services.  If you’re looking for a kiln for sale, or need service advice, contact us!