We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Machinery

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is a Rotary Kiln?

By Keith Koons
Updated: May 17, 2024
Views: 11,209
Share

A rotary kiln is a device that supplies tremendous amounts of heat in order to change the chemical composition of an object. It is made up of a strong reinforced steel outer shell that is coated with a heat-resistant inner lining, support rollers and a drive gear to keep the contents in a continuous rotating motion and internal heat exchangers capable of producing temperatures well over 2732 degrees Fahrenheit (1500 degrees Celsius). Rotary kilns will sit slightly at an angle so that the inner contents will be sifted downwards toward the heat source and allow for any evaporative gasses to escape from the top during the process through sealed ductwork. The contents are then sorted and ejected through an opening in the lower end of the device that automatically sorts processed materials and waste into separate bins. Other common terms to describe such a device may be a rotary kiln incinerator or a rotary kiln dryer.

Perhaps one of the most common uses for this technology is the creation of a rotary cement kiln, which grinds limestone, clay, and shale down to small bits of rock and transforms them into a usable cement mixture that is ready to be either packaged or immediately used. During this process, the materials are exposed to varying temperatures that will evaporate any water present and transform the limestone and clay back to their original oxide states. As the internal heat increases up to 2642 degrees F (1450 degrees C), the rocks that were transformed into belite and calcium oxide melt together to form the composition alite. Due to the extreme heat associated with this process, the resulting lumps of alite are no larger than 0.39 inches (10 mm) across and are easily handled once the cooling process is completed.

The rotary kiln design allows for many similar types of solids to be broken down into more readily usable materials, and it is commonly used on alumina, titanium dioxide and lime. Metakaolin, iron ore pellets, and many other metallic and non-metallic components may also be broken down by a rotary kiln. Refractory material, or a solid whose composition does not possess metal, but still remains suitable for construction, is also created using this method and ultimately installed inside rotary kilns and other furnaces as an insulator to protect the outer shells from the extreme internal temperatures.

Share
About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
Share
https://www.aboutmechanics.com/what-is-a-rotary-kiln.htm
Copy this link
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.