Kaolin rotary dryer Introduction

Kaolin rotary dryer is a kind of drying equipment that can handle a large number of wet kaolin powders. It has reliable operation, large operation flexibility, strong adaptability, large processing capacity, and strong adaptability of materials. It can dry various materials, and the equipment operation is simple and reliable. It is widely used in building materials, metallurgy, chemical industry, cement industry and so on. It can be used to dry iron ore, limestone, coal powder, slag, clay, and other materials, especially for iron ore pellet, slag slurry, effect is more obvious. After the wet material is added to the dryer, it is evenly distributed and dispersed in the dryer under the agitation of the flights or lifting plates, and fully contacts with the hot air in parallel (countercurrent) flow, which accelerates the drying heat transfer and mass transfer.

Kaolin rotary dryer structure

Dryer Shell: The rotary dryer shell is the main body of the dryer, where the material is loaded and rotated. It has a cylindrical shape and is equipped with lifting plates or flights to lift and disperse the material. The drum is heated by hot air or gas that flows through it, either in parallel or countercurrent direction. The drum transfers heat to the material and evaporates the moisture.

Dryer Flights: Rotary dryer flights, also known as "flights" or "lifters," are the inclined, curved structures that are attached to the internal shell of a rotary dryer. A rotary dryer is a device used to remove moisture from materials like powders, granules, and bulk solids through the process of drying. It consists of a large cylindrical drum that rotates while the material is fed into one end and is discharged from the other end after being dried.

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

Dryer pinion: The pinion is an essential part of the rotary dryer drive system, responsible for transmitting rotational motion and torque from the driving mechanism to the rotary dryer 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 dryer. When the pinion is rotated by the drive system, it drives the girth gear, causing the rotary dryer to rotate.

Dryer bearing housing: The bearing housing serves as the support structure for the dryer's rotating motion and is responsible for holding and guiding the dryer's trunnion bearings. Trunnion bearings are large, heavy-duty bearings that support the weight of the dryer 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 dryer. The bearing housing provides a stable mounting point for the trunnion bearings and ensures proper alignment of the dryer's rotation. It is typically designed to accommodate the axial and radial forces generated during the rotation of the dryer.

Dryer Hood Cover: The rotary dryer hood is located at the discharge end of the kiln and provides sealing to retain heat and gases. The rotary dryer 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 dryer Transmission device: The transmission device of the rotary dryer 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 dryer, 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 dryer and the quality of the products being processed. Usually, the rotary dryer 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 Kaolin rotary dryer

The design principles of a kaolin rotary dryer involve various considerations to ensure efficient and effective drying of kaolin clay while minimizing energy consumption and maintaining product quality. A rotary dryer is a type of industrial drying equipment that utilizes rotation to move material through heated air, allowing moisture to be evaporated.

Drying Chamber Configuration: The shape and size of the drying chamber can impact drying efficiency. A well-designed chamber should allow for proper mixing and tumbling of the material to ensure even exposure to heat.

Moisture Removal: The design should incorporate efficient mechanisms for removing evaporated moisture from the drying chamber to prevent reabsorption of moisture by the kaolin.

Product Quality: Ensuring that the kaolin's physical and chemical properties are not compromised during drying is crucial. The design should prevent excessive exposure to high temperatures that could affect the clay's characteristics.

Material Movement: The rotation of the dryer should be designed to facilitate the movement of the kaolin through the drying chamber. This movement prevents material buildup or uneven drying and promotes consistent exposure of the material to the heated air.

Temperature Control: Kaolin clay has specific temperature requirements to prevent degradation or altering of its properties. The design must include temperature control mechanisms to ensure that the clay is dried within the optimal temperature range.

Retention Time: The retention time, or the duration that the material spends inside the dryer, is critical for achieving the desired moisture reduction. The design should determine the appropriate retention time based on the initial moisture content of the kaolin.

Safety: Safety measures should be incorporated into the design to prevent overheating, fires, or other potential hazards associated with industrial dryers.

Maintenance and Accessibility: The design should allow for easy maintenance and cleaning of the dryer components. Accessibility to internal parts and mechanisms is important for regular upkeep.

Environmental Considerations: The design should also consider the environmental impact of the drying process, such as emissions, waste heat utilization, and resource efficiency.

Specifications of Kaolin rotary dryer

Note: *The initial moisture is assumed to be 2~6% and final moisture is 1~4%; Inlet temperature of hot air is 150~250 Celsius and outlet temperature is 70~90 Celsius; Production Capacity will vary according to the composition and moisture of the material.

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Industry Knowledge extension

What is the application of dried Kaolin? 

Dried kaolin, also known as kaolin clay or China clay, is a type of clay that is commonly used in various applications due to its unique properties. Kaolin is primarily composed of the mineral kaolinite and is valued for its versatility and ability to undergo various physical and chemical transformations. Here are some common applications of dried kaolin:

Ceramics and Pottery: Kaolin is a fundamental ingredient in the production of ceramics and pottery. It is used as a raw material in the clay body to provide structure, whiteness, and stability during firing. Kaolin helps control shrinkage, improve workability, and enhance the overall aesthetics of the finished ceramic products.

Paper Industry: Dried kaolin is used as a coating pigment and filler in the paper industry. It can improve paper's opacity, brightness, and smoothness while reducing the need for more expensive pulp. The addition of kaolin to paper also enhances ink receptivity and print quality.

Cosmetics and Personal Care Products: Kaolin is a common ingredient in cosmetics, skincare, and personal care products. It is used in products like face masks, facial cleansers, and body powders due to its absorbent and oil-absorbing properties. Kaolin helps cleanse the skin by removing impurities and excess oils.

Pharmaceuticals: Kaolin is used in pharmaceuticals as an excipient, which is an inert substance that is added to a medication to provide bulk and aid in the manufacturing process. It can also be used in some medications to treat diarrhea by adsorbing toxins and bacteria.

Paint and Coatings: Dried kaolin is used as a pigment extender and functional filler in the paint and coatings industry. It can improve the durability, opacity, and viscosity of paints, as well as provide anti-settling properties.

Rubber and Plastics: Kaolin is used as a reinforcing filler in rubber and plastic products. It enhances the mechanical properties of the materials, such as tensile strength, tear resistance, and abrasion resistance.

Catalysts and Chemicals: Kaolin can be used as a catalyst support in various chemical reactions due to its high surface area and thermal stability. It is also utilized in the production of alumina and other chemicals.

Porcelain and Fine China: Kaolin is an essential ingredient in the production of high-quality porcelain and fine china. Its unique properties contribute to the translucency, smooth texture, and pure white color of these ceramics.

What is the difference between rotary dryer and rotary kiln?

Rotary dryer: A rotary dryer is used to remove moisture from materials, such as minerals, ores, chemicals, food products, and biomass. The primary purpose of a rotary dryer is to reduce the moisture content of the material through the application of heat and the movement of the material within the drum. In a rotary dryer, materials are fed into the rotating drum, and hot gases or air are introduced to evaporate the moisture. The material is tumbled and agitated as it moves through the drum, allowing for efficient drying. Rotary dryers operate at elevated temperatures to facilitate drying, the temperatures used are generally lower compared to those in rotary kilns. Rotary dryers are used in industries such as agriculture, mining, chemicals, and food processing to remove moisture from bulk solids, powders, and other materials.

Rotary Kiln: A rotary kiln is designed for high-temperature processes, such as calcination, sintering, pyrolysis, and other thermal treatments. It's used to process raw materials or products at elevated temperatures, often in a controlled atmosphere, to bring about physical or chemical changes in the material. In a rotary kiln, materials are typically fed into one end of the kiln and gradually move towards the other end. The kiln is heated to very high temperatures, and the material undergoes chemical reactions, phase changes, or thermal treatments as it progresses through the kiln. Rotary kilns operate at much higher temperatures, often reaching well over 1000 degrees Celsius (1800 degrees Fahrenheit), depending on the specific process. These high temperatures are necessary to achieve the desired chemical or physical transformations in the material. Rotary kilns are used in industries such as cement production, lime calcination, metallurgy, and waste incineration. They are designed for processes that require high-temperature reactions, phase changes, or material transformation.