Spodumene rotary kiln Introduction

Spodumene rotary kiln is a kind of equipment specially designed for spodumene calcination. Spodumene can't store lithium without calcination. Separation of spodumene into concentrate requires calcination. Calcination is an important step in the purification of spodumene concentrate, which can eliminate harmful substances in spodumene and make it a purer concentrate. Usually, the spodumene is burned into concentrated lye and then calcined under high temperature conditions containing sodium hydroxide, which can effectively remove impurities in the spodumene, thereby obtaining high-purity concentrate products. During the operation of the Spodumene 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 Spodumene, 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.

Spodumene rotary kiln structure

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 spodumene rotary kiln

Designing a spodumene rotary kiln involves considering various principles to ensure efficient and safe operation. Spodumene is a mineral used in the production of lithium compounds, and a rotary kiln is a critical piece of equipment for processes like calcination, roasting, and other thermal treatments.

Gas Flow and Mixing: Adequate gas flow and mixing are essential to ensure uniform heating and reaction of spodumene. The kiln's design should include features like gas injection systems, baffles, and optimized airflow patterns to prevent hotspots and ensure thorough processing.

Kiln Rotation and Inclination: The rotation speed and inclination angle of the kiln influence material movement and residence time. These parameters should be carefully selected to achieve the desired processing outcomes while avoiding material agglomeration and uneven heating.

Refractory Material Selection: The selection of appropriate refractory materials is critical to withstand the high temperatures and harsh chemical environment inside the kiln. Refractories should have excellent thermal stability, mechanical strength, and resistance to chemical corrosion.

Kiln Length and Diameter: The kiln dimensions should be chosen to balance throughput requirements and material residence time. A longer kiln allows for more thorough processing, while a larger diameter can increase throughput.

Temperature Control and Monitoring: Incorporate temperature monitoring and control systems to ensure that the desired temperature profiles are maintained throughout the kiln length. This can involve the use of thermocouples, infrared sensors, and feedback control loops.

Emission Control: Depending on the process, the kiln might produce emissions that need to be controlled to meet environmental regulations. Consider incorporating emission control technologies like scrubbers, filters, and catalytic converters.

Specifications of spodumene rotary kiln

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

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Industry Knowledge extension

What is the application of calcined spodumene?

Calcined spodumene, also known as lithium spodumene or lithium metasilicate, is a processed form of spodumene ore that has undergone thermal treatment to remove impurities and convert it into a more useful and reactive material. Calcined spodumene is primarily known for its role in the production of lithium compounds, which are essential in various industries.

Lithium Carbonate: Calcined spodumene is a key raw material in the production of lithium carbonate, a vital component in lithium-ion batteries. It is used in rechargeable batteries for electric vehicles, consumer electronics, and renewable energy storage.

Lithium Hydroxide: Another major application is the production of lithium hydroxide, which is used in high-energy-density lithium-ion batteries and other advanced energy storage systems.

Ceramic Glazes: Calcined spodumene is used in ceramic glazes to enhance the brightness and color of the glaze. It can improve the melting behavior of glazes and promote desired surface effects.

Glass Production: It can be used as a fluxing agent in glass production to lower the melting point and improve the workability of glass.

Glass-Ceramics: Calcined spodumene is used in the production of glass-ceramics, which combine the properties of glass and ceramics. These materials find applications in cookware, glass cooktops, and other specialized products.

High-Temperature Ceramics: Calcined spodumene can be used as a component in heat-resistant ceramics due to its ability to withstand high temperatures.

Catalyst Support: Calcined spodumene can be used as a support material for catalysts due to its high surface area and thermal stability.

Solid Lubricants: In some cases, calcined spodumene can be used as a solid lubricant in high-temperature applications.

Thermal Insulation: Calcined spodumene can be used in the aerospace and defense industries for its thermal insulating properties.

Refractory Materials: Calcined spodumene can be utilized in refractory materials used in high-temperature industrial applications, such as furnaces and kilns.

Aluminum Smelting: It can be used as a fluxing agent in aluminum smelting processes to reduce the melting point and improve the efficiency of the process.

Specialty Materials: Calcined spodumene can be used in specialized electronic and semiconductor applications due to its thermal and electrical properties.

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.