Can a customized experimental rotary tube furnace be used for calcination experiments?

The customized experimental rotary tube furnace can be fully used for calcination experiments. Its rotating heating, precise atmosphere control, flexible customized design, and efficient heat transfer characteristics can meet the core requirements of calcination process for temperature uniformity, atmosphere environment, material mixing, etc. The following is a detailed analysis:

1. The core requirements of calcination experiments and the adaptability of rotary tube furnaces
High temperature environment and uniform heating
Calcination usually needs to be carried out at high temperatures (such as 800-1600 ℃), and uniform heat transfer is required to avoid local overheating or undercooking of the material. The rotating design of the rotary tube furnace allows materials to roll inside the furnace, achieving even heat distribution, which is significantly better than traditional static furnaces.
Example: When preparing alumina by calcining aluminum hydroxide, rotary heating can ensure synchronous dehydration of the particle surface and interior, avoiding cracking or agglomeration caused by temperature gradients, and resulting in a narrower particle size distribution in the final product.
Atmosphere control ability
The calcination process may require inert gas (such as nitrogen, argon) protection, oxidizing atmosphere (such as air), or reducing atmosphere (such as hydrogen) to control material oxidation, decomposition, or phase transition reactions. The rotary tube furnace can be customized with sealing systems (such as magnetic fluid seals or high-temperature resistant silicone rubber seals), supporting vacuum, inert gas, air, or mixed atmosphere environments.
Application Scenario:
When preparing calcium oxide by calcining calcium carbonate, air needs to be introduced to provide an oxidizing environment;
When calcining metal oxide precursors, an inert atmosphere is required to prevent metal reduction;
When calcining sulfide minerals, it is necessary to control the oxygen content to suppress excessive oxidation.
Material mixing and mass transfer enhancement
During the calcination process, the material may undergo decomposition, phase transition, or solid-phase reaction, and it is necessary to mix thoroughly to promote uniform reaction. The rotational motion of the rotary tube furnace can cause animal materials to roll and collide, enhance mass and heat transfer, and shorten reaction time.
Advantages: For viscous or agglomerative materials (such as hydroxide gel), rotation can prevent particles from sticking and ensure complete calcination; For multi-component mixtures, component segregation can be avoided.

2. The key direction of customized design
Optimization of furnace structure and material
High temperature resistance and thermal shock resistance: high-purity alumina fiber, silicon carbide or corundum materials are selected as furnace lining, which can withstand high temperatures above 1600 ℃ and resist thermal shock cracks caused by rapid heating/cooling.
Anti corrosion design: If acidic gases (such as SO ₂, CO ₂) are generated during the calcination process, a corrosion-resistant coating (such as yttria stabilized zirconia) should be applied to the inner wall of the furnace, or a quartz tube should be used as the reaction vessel.
Customization of heating system
Multi zone independent temperature control: supports segmented heating (such as preheating zone, reaction zone, cooling zone), optimizes temperature gradient, and adapts to the calcination curves of different materials. For example, when calcining barium titanate precursor, it is necessary to keep it at 300 ℃ for 2 hours to remove crystal water, and then heat it up to 800 ℃ for 2 hours to form perovskite phase.
Rapid heating capability: By customizing high-power heating elements (such as silicon carbon rods, silicon molybdenum rods) and optimizing the furnace structure, the heating rate can be increased and the experimental period can be shortened.
Customization of Rotation and Transmission Systems
Adjustable rotation speed: Supports stepless speed regulation to meet the calcination needs of different materials. For example, for powders with good fluidity (such as alumina), high-speed rotation strengthening mixing can be used; For viscous materials (such as hydroxide gel), rotate at low speed to prevent agglomeration.
Forward and reverse control: By alternating forward and reverse rotation, material agglomeration can be further disrupted and calcination uniformity can be improved.
Customization of feeding and discharging systems
Continuous feeding: equipped with a spiral feeder or vibrating feeder to achieve continuous and stable material transportation, avoiding batch differences. For example, in the preparation of calcium oxide by calcining limestone, continuous feeding can maintain a constant amount of material in the furnace and stabilize the reaction temperature.
Controllable discharge: By adjusting the inclination angle and rotation speed of the furnace tube, the discharge rate of the calcined product is controlled to prevent incomplete particles from being carried out.
Product collection and exhaust gas treatment
Multi stage cooling and collection: Install two-stage cooling devices (such as water-cooled sleeves and air coolers) at the outlet of the furnace tube to quickly cool the calcined product and prevent secondary reactions at high temperatures. At the same time, set up graded collectors (such as cyclone separators+bag filters) to separate products of different particle sizes.
Exhaust gas purification system: If harmful gases (such as SO ₂ NOx）， It is necessary to integrate exhaust gas treatment devices (such as wet flue gas desulfurization and catalytic oxidation) to meet environmental protection requirements.

3. Typical calcination experiment case
Inorganic material calcination
Experimental conditions: Preparation of alumina (α – Al ₂ O3) by calcining aluminum hydroxide (Al (OH) I3), temperature 1200 ℃, air atmosphere, rotation speed 5 rpm, and insulation for 3 hours.
Result: The purity of the alumina product has been improved and meets the requirements of the catalyst carrier.
Calcination of metal oxide precursor
Experimental conditions: Preparation of BaTiO3 by calcining the hydrolysis product of tetrabutyl titanate (TBOT), temperature 800 ℃, nitrogen atmosphere, rotation speed 2 rpm, and staged heating.
Result: The barium titanate product is a pure perovskite phase.
Mineral calcination
Experimental conditions: Preparation of calcium oxide (CaO) by calcining limestone (CaCO3), temperature 900 ℃, air atmosphere, rotation speed 10 rpm, continuous feeding.
Result: The activity of calcium oxide (T60) is greater than 300 seconds, which meets the requirements for lime used in steel smelting.