What is a rotary kiln? An ultimate beginner's guide to how to select a rotary kiln.


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A rotary kiln is a common piece of industrial equipment used to process and transform materials at high temperatures. It is a long, cylindrical vessel, usually placed horizontally and mounted at an inclination. The material enters the rotary kiln through the kiln tail and then gradually moves along the axial direction inside the kiln before it is finally discharged through the kiln head. The working principle of the rotary kiln is based on the thermal treatment and transformation of materials at high temperatures. By heating the material inside the rotary kiln, different treatment effects such as drying, calcining, roasting, incineration, smelting, gasification, etc. can be achieved, depending on the needs of the application and the process requirements.

What is the structure of a rotary kiln/incineration kiln?

The core parts of the rotary kiln can be divided into cylinder device, support device, transmission device and sealing device. Many customers have very high requirements for the quality of rotary kilns when purchasing rotary kilns. The rotary kiln manufactured by Tongli based on many years of manufacturing experience and combined with the most cutting-edge manufacturing technology has the advantages of high output and good stability.

Rotary Drum Cylinder:  The rotary dryer shell is the main body of the kiln, where the material is loaded and rotated. It has a cylindrical shape and is equipped with refractory linings. The drum is heated by the burner to generate hot air or gas that flows through it, either in parallel or countercurrent direction. The drum transfers heat to the material and cause chemical changes to the property of the material.


Supporting Device: rotary kiln supporting device is composed of the supporting roller and thrust roller, the shaft is a forged object to prolong the service life time of the rotary kiln. One thing features about Tongli Supporting device is all the metal casting are produced by our own, the quality is guaranteed. All the metal casting supporting roller, metal casting thrust roller are machined and heat treated, the performance measure is reliable.


Transmission Device: The rotary kiln shell is supported on multiple riding rings usually 2~3, which are attached to the shell with point-welded padding on the inside. The rotary kiln riding rings allow the kiln to rotate smoothly on its axis and help distribute the kiln's weight. The thickness of the plate under the riding ring is increased to facilitate strength of the shell.

What are the types of rotary kiln?

  • According to the feeding method: According to whether the materials entering the kiln contain water, they are divided into dry kilns and wet kilns. Wet kilns can be divided into inflow method and injection method.

  • According to the length-to-diameter ratio: The length-to-diameter ratio is the basis for dividing long kilns and short kilns. Generally, dry kilns have fewer working sections and the length-to-diameter ratio is less than 16, which is a short kiln. Wet kilns are generally long kilns. The aspect ratio is between 30 and 40. The drying process in the spray kiln is shortened and is somewhere in between.

  • According to kiln type: According to the geometric shape of the cylinder, it is divided into straight barrel kiln, cold end expanded kiln, hot end expanded kiln, firing zone expanded kiln and both ends expanded kiln.

  • According to the cooling method of the material: When multiple cooling cylinders are fixed at the hot end of the cylinder, it is called a kiln with a multi-cylinder cooler to distinguish it from a kiln with a separate cooler

  • Rotary kiln based on the transmission type can be separated into girth gear-pinion drive and friction drive rotary kiln, Tongli is an expert in the filed of manufacturing both of them.

  • Rotary kiln can also be divided into incineration rotary kiln and material processing rotary kiln based on its function, a material processing rotary kiln serves the function of processing material whereas the incineration rotary kiln is mainly used for waste material disposal.

  • According to the heating method, it can be divided into internal heating kiln and external heating kiln. Most kilns are internally heated kilns. In non-ferrous metallurgy and chemical plants, when the materials being processed are highly toxic or when high flue gas concentration and high product purity are required, external heating rotary kilns are also used, using electric heating wires or heavy oil to indirectly heat the materials outside the cylinder. Its diameter is generally small, so it is called a rotary tube.

How to select a rotary kiln? Top 10 rotary kiln manufacturer/supplier

  • Determine the specific requirements for your project, such as the size, capacity, temperature, and material handling capabilities of the rotary kiln. Also, consider any special features or customization you may need.

  • Look for suppliers with a strong reputation for quality and reliability. Check their track record by reading customer reviews, case studies, and testimonials. Consider how long they have been in the industry.

  • Assess the technical expertise of the supplier's team. They should have experienced engineers and technicians who can provide guidance and support throughout the project.

  • Visit the supplier's manufacturing facilities if possible. This will allow you to inspect the quality of their production processes and the materials used in their kilns. Look for modern and well-maintained equipment.

  • Ensure that the supplier adheres to relevant industry standards and certifications, such as ISO, CE, or other quality assurance standards. Compliance with safety and environmental regulations is essential.

Who is Zhejiang Tongli Heavy Machinery Co., Ltd

Founded in 1958 Zhejiang Tongli Heavy Machinery Co., Ltd is an equipment manufacturer very famous in China domestic market for making ball mill, vertical roller mill, rotary kiln and all sorts of cement & fertilizer production equipment, even though not as famous as FL Smidth, but Tongli is constantly improving to provide top-tier product and service to global customers. We are dedicated to cement & fertilizer equipment manufacturing. After reading this article, if you still want to know more about rotary kilns, you can follow our tongli official YouTube channel. We will update knowledge about rotary kilns, vertical mills, and ball mills from time to time. The link is attached below: Youtube:tongliheavymachinery3898

Date: 2023-9-26 

Author: Richard.Z