Indirect Rotary Calciners
Indirect Rotary Calciners
Range from steam tube rotary dryers/calciners through to high temperature <1,100oC calciners for both oxidative and reducing environment processing. Main mode of energy transfer is radiation and conduction
Specifications:
- Indirect rotary calciners are designed for numerous processing applications depending on the process requirements.
- The kilns can be designed for oxidative processes though to reducing processes and can handle fine material size distributions up to 10micron.
- The kilns can be configured with a single temperature zone or multiple zones and can operate up to 1,100degC without distortion to the selected construction material.
- Materials of construction can range from painted mild steel, through to various grades of stainless steel to special alloys depending on the processing environments and conditions.
- Heat sources range from steam, thermic oil, electric gas and liquid fuel burner systems
- All equipment is tailor designed to suit the processing requirements.
- A unique aspect of a Drytech indirect rotary kiln is our unique internal ceramic liner which allows the processing of highly corrosive environments without detriment to the product or equipment.
- This specific design allows for the process of REE, Hot Acid Leach process and high purity products.
- Other materials processed: spodumene, graphite, tin, tungsten, vanadium, titanium, REE, soda ash, kaolin, alumina, stibnite to name a few.
Feeding/discharge:
Automatic and continuous. Vibrators, screw feeders, rotary airlocks, double flap valves, gravity chutes
Feed Characteristics:
Powders, granules, non-friable agglomerates. Low to high feed rates <45tph
Heat Source:
Electrical, steam, gas, liquid fuel
Exposure:
Product contacts the heated surface of the drum. Special lifters turn the product exposing the new product to the heated surface.
Residence time:
Controllable. Residence time can be altered by varying the speed of rotation of the drum and the drum angle. Fill can be varied. Fills are typically between 5% and 20% of the cross-sectional area of the drum.
Extraction:
Normally induced but depends on the process requirements.
Dust Collection:
Systems can be low dust with minimal separation requirements.
If required cyclones, baghouses, scrubbers, Electrostatic precipitators.
Control:
PLC, infrequently solid-state controllers. System controls on discharge temperature. Can modulate energy and feed.
Benefits:
High throughput
Excellent energy utilization for electrical units
Can have zoned temperature profile
Gentle handling
Intimate product contact
High-temperature operation - can be refractory lined.
The unit can have an integral cooling section.
Limitations:
Incorrect seal design can cause leakage
Large real estate required
High temperature can cause damage to certain components
