Indirect Fired Calcination Rotary Kiln High Purity Chemical Processing

Indirect fired calcination rotary kiln for high-purity chemical processing

1.Product Introduction Calcination Rotary Kiln

The Indirect Heating Calcination Rotary Kiln is a continuous high-temperature thermal processing unit specifically designed for the preparation of high-purity chemicals. Its defining characteristic is the total physical isolation of the combustion system from the material processing zone. The equipment consists of an external combustion chamber, a high-temperature refractory insulation layer, a rotating inner cylinder, and sealed feeding/discharging units. Fuel (such as natural gas or LPG) burns within the external chamber, and heat is transferred to the internal materials via radiation and conduction through the cylinder walls. This "no-contact" heating design prevents combustion byproducts (such as ash, SOx, and NOx) from contaminating the material, ensuring a product purity of over 99.9%. It is ideal for sensitive materials like electronic-grade oxides, lithium-ion precursors, and pharmaceutical intermediates, with typical operating temperatures ranging from 1,000 to 1,400°C.

2.Application Calcination Rotary Kiln

• Li-ion Battery Cathode Precursors: Dehydration and phase transformation of nickel hydroxide or LCO precursors to ensure electrochemical consistency.
• Solar Lime Preparation: Utilizing clean heat sources to calcine limestone, producing carbon-free, high-activity  for green chemical engineering.
• Low-Temperature Coal Pyrolysis: Pyrolyzing low-rank coal under inert atmospheres to obtain high-purity tar and semi-coke for fine chemical synthesis.

3.Working Principle Calcination Rotary Kiln

• Thermal Isolation Conduction: Fuel burns completely within an independent combustion chamber. High-temperature flue gases never enter the material zone; instead, heat is transferred through the metallic inner cylinder wall primarily via thermal radiation, supplemented by convection, achieving "clean heating."

• Rotational Axial Transport: The inner cylinder rotates slowly (1–5 rpm). Driven by gravity and a cylinder inclination of 3–5°, the material moves at a constant speed from the feed end to the discharge end, ensuring uniform heating and complete reaction.

• Temperature Gradient Modeling: Based on one-dimensional heat conduction models, a multi-zone temperature control system manages the axial temperature distribution (Preheating, Calcination, and Cooling zones) to optimize reaction kinetics.

• Airtight Isolation Design: The inlet and outlet utilize multi-stage sealing structures (such as graphite seals or gas seals) to prevent ambient air infiltration or process gas leakage, maintaining a pure reaction environment.

4.Advantages Calcination Rotary Kiln

•  Ultra-High Product Purity: Zero contact between combustion gases and material eliminates contamination from fuel ash, sulfur, or chlorine. Purity is significantly superior to direct-fired kilns.
•  Uniform and Controllable Temperature: Radiative heat transfer ensures more uniform material heating, with temperature variances kept within ±10°C, enhancing crystalline stability.
•  Strong Process Adaptability: Supports oxidizing, reducing, or inert atmosphere operations to meet diverse chemical reaction path requirements.
•  Significant Energy Optimization: Equipped with waste heat recovery systems (e.g., preheating feed or combustion air), achieving a thermal efficiency of over 65% and reducing unit energy consumption by over 30%.
•  Stable and Reliable Operation: The modular structure is easy to maintain. High-grade alloy inner cylinders and refractories provide a long service life, suitable for 24/7 industrial operation.
•  High Environmental Compliance: No direct emission pollution, complying with EU REACH, China’s "Pollutant Discharge Standards for the Battery Industry," and other green manufacturing regulations.

5.Technical Specifications

6.Our Solutions