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 Furnace?

By M.J. Casey
Updated: May 17, 2024
Views: 7,323
Share

A rotary furnace, also called a rotary kiln, is a long tube that is used as a continuous plug flow reactor in the mineral industry. The mineral feed is introduced to the reactor portion and is transported down the length of the tube while the tube slowly rotates around its central axis. The materials are mixed as well as heated. The original designs were applied to the calcination treatment in the production of Portland cement and in the extraction of mercury from ores. These reactors are used frequently for the recovery of valuable metals.

A typical rotary furnace is made from a single sheet of steel wrapped into a cylinder with a diameter of about 3 ft to 6 ft (0.9 m to 1.8 m) and a length of about 30 ft to 60 ft (9.1 m to 18.3 m). In one common drive configuration, the tube is rolled on smooth stainless steel rings that rest on two stainless steel rotating rollers. Usually, there are multiple heat zones. The heat may be applied via the hot gas discharge from the fuel, or the fuel may be fired directly into the tube. The transformed product is discharged after being cooled in a cooling section where heat is recovered and sent back to the combustion air.

Screw conveyors or simple threaded rods can be used in a separate rotary furnace design in which more mixing is desired. Another configuration consists of a reverberating design in which material is shaken down the tube. The rotary furnace design is modified by a tilt mechanism that allows liquid metal to drain from the reactor. This design is very useful in the extraction of metals from ores or from recycled materials, such as copper, gold, and mercury.

Fuel is limited to high-energy content fuels, such as oil, gas, or fluidized coal since high temperatures are required. The high-energy requirement to melt metals also explains the use of direct contact with the combustion flame in some designs. The combustion gases are generally passed counter-current to the material flow. Controls include feed rates, temperature zones, and rotation speeds. Many companies now provide complete systems that are either of standard design or custom engineered for the applications.

A variation of the rotary furnace is a batch process that consists of a rotating vessel that is titled on its side. The heat is supplied through the free space above the liquid. When the metal is melted, the vessel is tilted, and the metal is poured into molds. This is a common design for the recycling of aluminum cans, as the cans are primarily aluminum and organic materials that can be burned off during the melting process.

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-furnace.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.