Industrial multi temperature zone rotary furnace powder drying

The industrial multi temperature zone rotary furnace has significant advantages in the field of powder drying. Through dynamic rotation, independent temperature control in multiple temperature zones, and flexible atmosphere adjustment, it can efficiently and uniformly complete powder drying tasks, especially suitable for powder materials that are thermally sensitive, prone to agglomeration, or require strict control of the drying environment. The following is a specific analysis:

1. The core requirements for powder drying and the adaptability of rotary furnaces
temperature uniformity
Powder drying should avoid local overheating that may cause material denaturation or agglomeration. The rotary furnace can achieve temperature field uniformity within ± 5 ℃ through dynamic rotation (continuous rolling of materials) and segmented temperature control, which is much better than the ± 10 ℃ deviation of static drying equipment (such as ovens). For example, in pharmaceutical grade micro powder drying, dynamic heating can prevent the degradation of drug active ingredients.
Drying efficiency
The continuous feed discharge design of the rotary furnace (such as spiral propulsion or gravity feeding) can achieve 24-hour uninterrupted drying, and the single line production capacity can reach tons per day. Dynamic rolling ensures full contact between powder and hot air, increases evaporation rate, and shortens drying cycle.
Atmosphere control
Some powders, such as organic materials and metal powders, require inert gas (N ₂, Ar) protection during drying to prevent oxidation, or a vacuum environment to lower the boiling point. The rotary furnace can be equipped with multiple gas pipelines or vacuum systems to achieve zone atmosphere control. For example, the drying of lithium-ion battery cathode materials (NCM) needs to be carried out in an environment with an O ₂ concentration of<1% to prevent oxidation of nickel and cobalt elements.
Anti agglomeration design
Powder drying process is prone to agglomeration due to surface tension or electrostatic effects. The rotational motion of the rotary furnace can break the bridging between powders, and with the assistance of vibration or airflow, it can increase the looseness of the dried powder and reduce the deviation of particle size distribution D50.

2. Typical powder material drying applications
a. Pharmaceutical grade micro powder drying
Case: Antibiotic raw materials (such as amoxicillin)
Requirement: The drying temperature should be strictly controlled at 50-60 ℃ to avoid degradation of active pharmaceutical ingredients; The powder particle size should be uniform to prevent needle blockage during injection.
Rotary furnace scheme:
Adopting a 6-zone temperature control system, the front section is preheated at a low temperature of 40 ℃ to remove surface water, the middle section is rapidly evaporated at a high temperature of 55 ℃, and the rear section is cooled at a low temperature of 50 ℃ to balance moisture.
The dynamic rotation speed can be adjusted (5-15rpm), combined with nitrogen protection (O ₂ concentration<0.5%), resulting in lower moisture content and greater looseness of the powder after drying.
b. Drying of battery material powder
Case: Three element positive electrode material (NCM811)
Requirement: The drying temperature should be controlled at 120-130 ℃ to avoid the decomposition of Li ₂ CO ∝; It needs to be carried out in an O ₂ atmosphere to prevent oxidation of nickel and cobalt elements; The powder needs to be loose and non agglomerated to improve the dispersibility of the slurry.
Rotary furnace scheme:
Adopting 8-zone temperature control, the adsorption water is removed at a low temperature (80 ℃) in the front section, the crystallization water is removed at a high temperature (125 ℃) in the middle section, and the grain growth is prevented by rapid cooling in the rear section.
Configure an O ₂ concentration monitoring system that automatically adjusts the intake air volume to ensure stable O ₂ concentration in the furnace.
Dynamic rotation combined with airflow rolling results in greater powder looseness after drying, with a particle size distribution D50 of 8-12 μ m, meeting the requirements of the coating process.

3. Technical advantages support powder drying
Dynamic heating uniformity
The materials continue to roll inside the furnace, eliminating the “dead corners” problem of static drying equipment and ensuring that all powder particles are heated uniformly. For example, in the drying of pharmaceutical micro powders, dynamic heating can improve the uniformity of water evaporation rate and reduce the risk of local overheating.
Flexible regulation in multiple temperature zones
Different temperature zones (such as preheating section, evaporation section, equilibrium section) can be set according to the characteristics of the powder to achieve complex temperature curves. For example, during the drying of battery materials, the first stage removes adsorbed water at low temperature, the middle stage removes crystallization water at high temperature, and the second stage rapidly cools to prevent grain growth.
Atmosphere and pressure zoning control
Support partition design with inert atmosphere in the front section, vacuum environment in the middle section, and natural cooling in the back section to meet the full process requirements of powder drying. For example, in the drying of food additives, the first stage is deoxygenated with N ₂, the middle stage is vacuum reduced to lower the boiling point, and the second stage is naturally cooled to retain nutrients.
Anti agglomeration and continuous production
Dynamic rotation combined with vibration or airflow assistance can effectively disrupt powder agglomeration and improve product looseness. At the same time, the continuous feed discharge design enables large-scale production with high consistency between batches.