Ceramsite rotary kiln

The ceramsite rotary kiln is a non-metallic aggregate calcination equipment. Ceramsite is a lightweight aggregate produced by foaming in a rotary kiln. It has a spherical shape, a smooth and hard surface. In the refractory industry, ceramsite is mainly used as the aggregate of heat-insulating refractory materials. Ceramsite has excellent properties, such as light weight, corrosion resistance, frost resistance, earthquake resistance and good insulation. therefore it is widely used in building materials, refractory insulation materials, chemical industry, petroleum and other industries.

Ceramsite rotary kiln Introduction

The ceramsite rotary kiln is a non-metallic aggregate calcination equipment. Ceramsite is a lightweight aggregate produced by foaming in a rotary kiln. It has a spherical shape, a smooth and hard surface. In the refractory industry, ceramsite is mainly used as the aggregate of heat-insulating refractory materials. Ceramsite has excellent properties, such as light weight, corrosion resistance, frost resistance, earthquake resistance and good insulation. therefore it is widely used in building materials, refractory insulation materials, chemical industry, petroleum and other industries. During the operation of the ceramsite rotary kiln, the slurry that has been homogenized to meet the is fed requirements into the kiln by the feeder at the kiln head to calcine the ceramsite, and the fuel is injected from the kiln head and burned in the kiln, and the heat emitted is heated to the raw material. The raw material is calcined and finish product is discharged from the bottom of the kiln shell, enters the cooling machine, and is collected after cooling.

Ceramsite rotary kiln structure

A ceramsite rotary kiln is the equipment used in the production of ceramsite. The rotary kiln is a cylindrical vessel, inclined slightly to the horizontal, which is rotated slowly about its axis. The raw materials, such as clay or shale, are fed into the upper end of the kiln, and as the kiln rotates, they move gradually towards the lower end. During this process, the materials are subjected to high temperatures, causing them to expand and form the porous ceramsite pellets.The ceramsite rotary kiln is composed of rotary kiln hood cover, rotary kiln shell, rotary kiln riding ring, rotary kiln girth gear, rotary kiln transmission unit and so on.

Riding Rings(Tyre): 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.

Girth Gear: The rotary kiln girth gear is a large gear ring encircling the kiln, usually mounted on the kiln shell. It is driven by a pinion gear, and together they form the primary drive unit to rotate the kiln. Under the girth gear is the spring plate, the function of the spring plate is to reduce heat transfer from the shell to the girth gear to prolong the service life time of the equipment.

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.

Rotary kiln thrust roller:The thrust roller is a critical part of the rotary kiln system. It serves the purpose of supporting the kiln's weight and maintaining its axial position, ensuring that the kiln remains properly aligned along its axis. The thrust roller is typically positioned on the downhill side of the kiln and is attached to the kiln shell, it consists of a central shaft or journal and a roller assembly.

Rotary kiln pinion: The pinion is an essential part of the rotary kiln drive system, responsible for transmitting rotational motion and torque from the driving mechanism to the rotary kiln itself. It consists of a gear wheel with teeth that mesh with the teeth of a larger gear, often referred to as the "girth gear" or "ring gear." The girth gear is attached to the outer shell of the rotary kiln. When the pinion is rotated by the drive system, it drives the girth gear, causing the rotary kiln to rotate.

Rotary kiln bearing housing: The bearing housing serves as the support structure for the kiln's rotating motion and is responsible for holding and guiding the kiln's trunnion bearings. Trunnion bearings are large, heavy-duty bearings that support the weight of the kiln and allow it to rotate smoothly. These bearings are subject to high loads, extreme temperatures, and potentially harsh environments due to the nature of the processes occurring inside the rotary kiln. The bearing housing provides a stable mounting point for the trunnion bearings and ensures proper alignment of the kiln's rotation. It is typically designed to accommodate the axial and radial forces generated during the rotation of the kiln.

Kiln Shell: The rotary kiln shell is a thick, steel cylindrical structure that provides the necessary strength and rigidity to withstand the high-temperature environment inside the kiln. It also serves as a containment vessel for the materials and gases during the manufacturing process. Inside the kiln shell is the refractory lining usually refractory bricks or sometimes refractory castable. Tongli kiln shell has good sealing performance, the edge of each shell is machined smoothly, enhance the sealing and service life of the rotary drum.

Kiln Hood Cover: The rotary kiln hood is located at the discharge end of the kiln and provides sealing to retain heat and gases. The rotary kiln operates under the negative pressure, therefore Tongli implied SS304 lining plate and ceramic felt both in the front and back end to prevent heat leakage.

Rotary Kiln Transmission device: The transmission device of the rotary kiln is mainly composed of main transmission, auxiliary transmission, mechanical thrust roller/hydraulic thrust roller, motor, gearbox and other components. The unique design of tongli transmission can greatly improve the service life and safety performance of the equipment.

PLC control system: A PLC is a digital computer-based system that is designed to control various industrial processes automatically. In the context of a rotary kiln, a PLC is used to monitor and control parameters such as temperature, rotation speed, air flow, fuel flow, and other critical variables that affect the performance of the kiln and the quality of the products being processed. Usually, the rotary kiln control system is integrated in the whole factory’s plc system, therefore we will provide the on-site cabin and a signal cable to the central plc.

Design principles of ceramsite rotary kiln


Sealing: Both the inlet and the outlet has a hood cover which improves the sealing effect, integrates labyrinth sealing, ceramic felt sealing, double leaf sealing, ss304 fish scale sealing to remain heat escape inside the kiln.

Filler padding: Floating padding are used under the riding ring to strengthen the shell and reduce the heat induction to the riding ring.

Girth gear spring plate: Due to the high temperature of the rotary kiln, Tongli magnesium rotary kiln is equipped with spring plate that is attached in between the girth gear and the shell to ensure smooth rotation and reduce heat transfer.

Girth gear/riding ring: All the metal casting are quality assured, Tongli has its own foundry and from the raw material to the finished product, the quality is reliable.

Quality inspection: Tongli offers magnetic testing and ultrasonic testing, which ensures the quality of all the metal castings and the welding seam.

Inlet and Outlet Design: The design of the inlet and outlet systems should promote a smooth flow of raw materials into the kiln and discharge of the processed ceramsite. This helps prevent blockages and ensures consistent production.

Temperature Control: Precise temperature control is essential for producing high-quality ceramsite with consistent properties. The kiln should be equipped with temperature monitoring and control systems to maintain the desired temperature profile throughout the process.

Rotational Speed: The rotation speed of the kiln affects the mixing and movement of the ceramsite inside. It should be optimized to ensure proper agitation and even heating.

Airflow and Gas Distribution: Proper airflow and gas distribution within the kiln are critical for uniform heating and chemical reactions. This might involve designing the kiln with features like baffles or using secondary air injection systems.

Cooling Zone: A cooling zone near the kiln's outlet helps stabilize the ceramsite's properties and prevent overfiring. Proper cooling rates are crucial to avoid deformities and ensure the desired final product quality.

Control Systems: Advanced control systems, such as programmable logic controllers (PLCs) and supervisory control and data acquisition (SCADA) systems, can be integrated to automate and optimize the kiln's operation, including temperature, rotation, and other process parameters.

Specifications of ceramsite rotary kiln


Capacity: (t/day)


Thrust Type

Power: (kw)

Weight: (tons)















































































Note: *The diameter is the inner diameter, Weight excludes refractory material.


Modern intelligent processing base integrating R&D, production and sales.

Zhejiang Tongli Heavy Machinery Manufacturing Co., Ltd (Formerly known as Tongxiang Coal&Mining Machinery Factory) established in year 1958 is a member of the Chinese National Building Material Machinery Association. Tongli is on the vendor list of designated production enterprise of the Ministry of Coal Industry. ISO9001、ISO14001、ISO45001 certified, accredited as High-tech & new technology enterprise of Zhejiang Province. With 65+ years of experience, Tongli has earned first class R&D and manufacturing capabilities, dedicated to provide satisfactory manufacturing equipments for global customers.   


Machines & Equipments

After years of development, there are more than 650+ sets of heavy machinery manufacturing equipments in our workshop, some of them are as follows:

Ф12m CNC Horizontal Lathe
Ф12m CNC Horizontal Lathe

One of the largest equipment in our factory, the maximum processing diameter is 12 meters, and the maximum processing length can reach 26 meters. This Lathe is specially crafted for processing mega cylinders.

Ф12m CNC Vertical Lathe
Ф12m CNC Vertical Lathe

One of the super-large equipment in our factory, the maximum processing height can reach 6 meters, and the maximum processing diameter can reach 12 meters, which ensures that the accuracy of the cylinder flange can reach the required level.

Ф5.3x18M CNC Horizontal Lathe
Ф5.3x18M CNC Horizontal Lathe
One of our advanced equipment for machining the Barrel, milling the end face and out surface with precision 0.05mm.
180mm CNC Universal Bending Machine
180mm CNC Universal Bending Machine
Numerical control with high precision, Maximum Bending Thickness : 180mm
Ф6.5х20m large annealing furnace
Ф6.5х20m large annealing furnace
Annealing will make the metal inner organization reach or near equilibrium, to obtain the good performance .By this large Furnace, we can anneal the shell by whole.
Ф6.5х20m Sandblasting room
Ф6.5х20m Sandblasting room
Remove all the rust and other impurities on the surface by sandblasting in this room to prolong the service life of the Painting.
4x12m Gantry CNC boring and milling machine
4x12m Gantry CNC boring and milling machine
  • Workbench effective size: 4000*12000mm;

  • Gantry Width: 4900mm;

  • Processing height: 4000mm;

  • Three angled milling heads, square ram;

  • Load-bearing 350 tons;

  • CNC system: SIEMENS 840D.

GKU40Ex80 Moving Beam Gantry Five-sided Machining Center
GKU40Ex80 Moving Beam Gantry Five-sided Machining Center
  • Workbench effective size: 3000*8000mm;

  • Gantry width: 4100mm;

  • Load-bearing: 80t;

  • Spindle speed: 2000RPM

  • CNC system: SIEMENS 840D.
2x4m Newway PM2040HA Moving Beam Gantry Machining Center
2x4m Newway PM2040HA Moving Beam Gantry Machining Center
  • Workbench effective size: 2000*4000mm; 

  • Processing Width: 2800mm;

  • Processing Height: 1100mm;

  • Full-CNC milling heads;

  • PLC: Siemens.
5x14M Vertical Boring&Milling Machine
5x14M Vertical Boring&Milling Machine
  • Workbench effective size: 4500x5000mm

  • Processing Length: 14000mm;

  • Processing Height: 5000mm;

  • CNC system: SIEMENS 840D.

  • Workbench effective size: 5000x5000m;

  • Processing Length: 11000mm;

  • Processing Height: 6300mm;

  • CNC system: SIEMENS 840D.
Ф12m and Ф10m Gear Hobbing Machine
Ф12m and Ф10m Gear Hobbing Machine
The required equipment to machine the girth gear, the maximum diameter of our gear-hobbing machine is 10m and the maximum module is 40.
Ф16х5m CNC Cutting Machine
Ф16х5m CNC Cutting Machine
Ensure precision of steel plate and other raw materials, avoid the error of manual operation.
Ф16х5m Edge Planer
Ф16х5m Edge Planer
Remove the burrs to make the welding preparation of steel plate have good roughness and ensure the angle of welding preparation angle.
Three-Phase Electric Arc Furnace
Three-Phase Electric Arc Furnace
Raw Materials for casting is produced from our own workshop to ensure the quality of the casting. 

Honors and Qualifications

Features of Tongli ceramsite rotary kiln


Energy Efficiency

Tongli rotary kilns are designed to be energy efficient, with features like pre-heaters and calciners that recover and reuse waste heat, and ss304 lining and ceramic felt to improve the sealing effect.


Precise Control

Adcanced instrumentation and control systems are employed to monitor and regulate the kiln's operation, ensuring stable and consistent production process.


Patented Design

Tongli held independent intellectual property rights, developed core technologies of mechanical, and electrical systems provide high reliability at all events.



Tongli rotary kiln can handle a wide range of materials with varying size and property, which is suitable for different types of production.

Industry Knowledge extension

What is the application of calcined ceramsite?

Calcined ceramsite, also known as expanded clay aggregate (ECA) or lightweight expanded clay aggregate (LECA), is a lightweight, granular material produced by heating natural clay to a high temperature. Calcined ceramsite has a range of applications in various industries due to its unique properties.

Lightweight Concrete: Calcined ceramsite can be used as lightweight aggregate in concrete to reduce the overall weight of structures while maintaining strength.

Insulating Concrete: It is used in the production of insulating concrete for applications requiring thermal insulation, such as roofs and walls.

Geotechnical Applications: Calcined ceramsite can be used for lightweight fill in embankments, retaining walls, and slopes, reducing the load on the underlying soil.

Soil Amendment: Calcined ceramsite can be added to soil to improve its drainage, aeration, and water retention properties, promoting healthy plant growth.

Hydroponics and Aquaponics: It is used as a substrate in hydroponic and aquaponic systems to support plant growth without soil.

Biofiltration Media: Calcined ceramsite can be used as a filtration media in biological filters for wastewater treatment systems, helping to remove organic matter and pollutants.

Water Purification: It can be used in water purification systems to remove impurities and contaminants through physical and chemical processes.

Oil Absorbent: Calcined ceramsite can be used as an absorbent material to clean up oil spills in both aquatic and terrestrial environments.

Gardening and Landscaping: Calcined ceramsite is used in gardening and landscaping to create lightweight and decorative elements like pots, planters, and artificial rock formations.

Thermal Insulation: Calcined ceramsite can be used in the production of lightweight insulation materials for applications such as fire-resistant insulation boards.

Structural Lightweight Fill: Calcined ceramsite can be used as lightweight fill material in construction projects where load reduction is desired.

Refractory Applications: In some cases, calcined ceramsite with high refractoriness can be used in the production of refractory materials, such as lightweight refractory bricks.

Sports Field Drainage: Calcined ceramsite is used in the construction of sports fields to improve drainage and prevent waterlogging.

Aquaculture Substrate: It can be used as a substrate in aquaculture tanks to provide a habitat for beneficial bacteria and support the growth of aquatic organisms.

What is the difference between rotary kiln and vertical roller mill?

The rotary kiln and vertical roller mill are both essential pieces of equipment in the cement manufacturing process, but they serve different purposes and are used at different stages of the process.

The rotary kiln is a large cylindrical vessel used for calcining raw materials at high temperatures. It's a core component of the cement manufacturing process and is responsible for transforming raw materials, particularly limestone and clay, into clinker. In the rotary kiln, the raw materials are heated to temperatures exceeding 1400°C (2552°F), where chemical reactions occur that result in the formation of clinker nodules. And they need to be ground into a fine powder to produce cement. This final grinding process is often performed using a vertical roller mill. The clinker is mixed with gypsum and possibly other additives to create the final cement product.

Vertical Roller Mill (VRM): The vertical roller mill is a grinding machine that grinds materials into fine powders, after the raw material is crushed by the crusher, it enters the vertical roller mill. It is typically used for grinding raw materials, clinker, and additives in the cement manufacturing process. The VRM operates by applying hydraulic pressure and vertical force to the grinding rollers, which then grind the materials between the rollers and the grinding table. This grinding process results in a fine powder that is later used as a key ingredient in the production of cement which is important for the subsequent chemical reactions in the rotary kiln.