Operating Principle

The drying unit for quartz sand operates based on a combination   of heat exchange and mass transfer   with   mechanical transportation . The working process consists of four key stages:   loading and supplying hot air ,  heat exchange and drying ,  material transportation   and   moisture removal and unloading .

1. Stage of loading and supplying hot air

Material loading:

• Wet quartz sand continuously enters the rotating drum installed at an incline
• The drum rotates slowly at a certain speed (usually 3-8 rpm)
• Under the influence of gravity and the drum's incline, the material moves toward the discharge end

Heat supply:

• The heat generator or burner produces high-temperature hot air (150-600℃)
• Hot air enters the drum from the loading or discharge side
• Typical flow schemes: co-current (hot air and material move in the same direction) or counter-current (in opposite directions)

2. Stage of heat exchange and drying

Action of lifting blades:

• Lifting blades (attachments, paddles) are installed on the inner wall of the drum
• As the drum rotates, the blades continuously lift the material
• The material falls in the form of an even "curtain"

Intensive heat exchange:

• The lifted material fully contacts the hot gas flow
• The contact area significantly increases, resulting in high heat transfer efficiency
• Moisture on the surface and inside the material evaporates quickly

Moisture evaporation process:

• Evaporation of surface moisture   (external diffusion): moisture from the material surface directly evaporates into the hot gas flow
• Migration of internal moisture   (internal diffusion): moisture from inside the material moves to the surface
• Vaporization with heat absorption : moisture evaporation absorbs heat, temperature rises

3. Stage of material transportation

Mechanical transportation:

• The drum is installed at an incline (inclination angle 3-5°)
• Under the combined action of gravity and drum rotation
• The material gradually moves from the upper end to the lower end

Residence time control:

• The drum rotation speed regulates the material's residence time
• The drum's inclination angle regulates the material's movement speed
• Ensuring complete drying of the material, achieving the required moisture content

Zonal drying:

• Loading zone : material intake, initial heating
• Lifting zone : main drying zone, high blade density, intensive heat exchange
• Discharge zone : drying completion, material temperature reduction, preparation for unloading

4. Stage of moisture removal and unloading

Removal of moist air:

• Evaporated water vapor exits the drum with the gas flow
• Cleaning through a dust collection system
• After meeting standards, it is released into the atmosphere or utilized

Unloading of dried product:

• Dried quartz sand is unloaded from the discharge end
• Moisture is reduced to the required technological level (usually ≤0.5-1%)
• Product temperature is moderate, ready for packaging or the next technological process

Continuous cycle:

• Loading, drying, and unloading occur simultaneously and continuously
• High productivity, large throughput
• Implementation of automated continuous production