Rotary kilns are advanced thermal processing tools utilized for chemical reactions and physical changes in solid materials through high temperatures, with applications in industries such as mineral roasting, waste incineration, and catalyst activation. They can be either direct-fired or indirect-fired, influencing the processing environment and material behavior. As a versatile technology, rotary kilns are critical to various industrial processes and continually see new applications and developments.

1. Rotary Kilns
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2. Rotary kilns are an advanced thermal
processing tool used to cause a chemical
reaction or physical change in a solid
material through the application of
high temperatures.

3. Rotary kilns are commonly used to carry out
processes such as:

4. Rotary kilns are commonly used to carry out
processes such as:
• Calcination

5. Rotary kilns are commonly used to carry out
processes such as:
• Calcination
• Thermal Desorption

6. Rotary kilns are commonly used to carry out
processes such as:
• Calcination
• Thermal Desorption
• Organic Combustion

7. Rotary kilns are commonly used to carry out
processes such as:
• Calcination
• Thermal Desorption
• Organic Combustion
• Heat Setting

8. Rotary kilns are commonly used to carry out
processes such as:
• Calcination
• Thermal Desorption
• Organic Combustion
• Heat Setting
• Sintering/Induration

9. Rotary kilns are commonly used to carry out
processes such as:
• Calcination
• Thermal Desorption
• Organic Combustion
• Heat Setting
• Sintering/Induration
• And more…

10. Rotary kilns were originally developed for use
in the cement industry. However, their flexibility
in processing quickly pushed them into a
variety of industries, both for processing
commodities, as well as for highly specialized
processing applications.

11. Rotary kilns have become the backbone of
many of the industrial processes that make our
world a more efficient and sustainable place.

12. Rotary kilns have become the backbone of
many of the industrial processes that make our
world a more efficient and sustainable place.
As new applications continue to be
developed, much research and development
is being done around these versatile thermal
processing machines.

13. Today, they are used for a multitude of
applications, including:

14. Today, they are used for a multitude of
applications, including:
• Mineral Roasting

15. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering

16. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining

17. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation

18. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration

19. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants

20. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants
• Upgrading of Phosphate Ores

21. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants
• Upgrading of Phosphate Ores
• Catalyst Activation

22. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants
• Upgrading of Phosphate Ores
• Catalyst Activation
• Ceramics Processing

23. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants
• Upgrading of Phosphate Ores
• Catalyst Activation
• Ceramics Processing
• Plastics Processing

24. Today, they are used for a multitude of
applications, including:
• Mineral Roasting
• Proppant Sintering
• Gypsum and Bauxite Calcining
• Activated Carbon Production & Re-Activation
• Waste Incineration
• Desorption of Soil Contaminants
• Upgrading of Phosphate Ores
• Catalyst Activation
• Ceramics Processing
• Plastics Processing
• And more…

25. How
Rotary Kilns Work

26. Rotary kilns work by holding the material
to be processed at a specific temperature
for a set amount of time.

27. Rotary kilns work by holding the material
to be processed at a specific temperature
for a set amount of time.
The temperature profile and retention time
are determined through thorough
chemical and thermal analyses of the
material, which allow process experts to
know at what temperatures reactions will
occur and for how long material will need
to be held at a certain temperature.

28. A rotary kiln is comprised of a rotating
cylinder (referred to as the drum), which is
sized in relation to the time and
temperature requirements of the material
to be processed.

29. A rotary kiln is comprised of a rotating
cylinder (referred to as the drum), which is
sized in relation to the time and
temperature requirements of the material
to be processed.
The drum is set at a slight angle, in order to
allow gravity to help move material
through the drum.

30. Rotary kilns can be either of the direct-fired
type, or the indirect-fired type.

31. Rotary kilns can be either of the direct-fired
type, or the indirect-fired type.
Direct-fired kilns rely on direct contact
between the material and the process gas in
order to process the material.

32. DIRECT-FIRED KILN

33. Conversely, indirect-fired kilns process material
in an inert environment, avoiding direct
contact between the material and processing
medium.

34. Conversely, indirect-fired kilns process material
in an inert environment, avoiding direct
contact between the material and processing
medium.
This is carried out by enclosing the drum in a
heat shroud, which is externally heated. The
material is heated through contact with the
shell of the drum.

35. INDIRECT-FIRED KILN

36. Rotary kilns can also be designed in a
co-current or counter current configuration,
which refers to the direction of the air flow in
relation to the material.

37. A variety of material characteristics will
influence how the material will behave in the
rotary kiln. These characteristics must be
prepared for and designed around in order to
reach the desired end product results.

38. A variety of material characteristics will
influence how the material will behave in the
rotary kiln. These characteristics must be
prepared for and designed around in order to
reach the desired end product results.
For this reason, testing is recommended to
work out process variables and provide data
for a commercial size unit.

39. Conclusion
Rotary kilns are a critical component in many
industrial processes, with new applications
being developed all the time. They are
available in the direct-fired and indirect-fired
type, with many customizations available.

40. has been a leader in the thermal processing
industry since the 1950s, providing process &
product development, feasibility testing,
maintenance services, and high-quality,
custom rotary kilns.

41. Want to learn more?
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Rotary Kiln Handbook
The Rotary Kiln Handbook
Rotary Kiln Sizing & Design
Processing Challenges
Service & Maintenance
And more…
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