Comminution Circuit Design
Comminution (crushing and grinding) is typically the most energy-intensive process in mineral processing, often consuming 30-50% of total plant energy. Proper circuit design is critical for efficient operation.
Crushing Circuits
Open Circuit Crushing:
- Material passes through crusher once
- Simple operation, no pre-screening
- Variable product size
- Less efficient than closed circuit
Closed Circuit Crushing:
- Screen oversize returns to crusher
- Consistent product size
- Higher efficiency
- Requires screen and conveyors
Grinding Circuits
AG/SAG Mills:
- Autogenous: Uses ore itself as grinding media
- Semi-autogenous: Uses ore plus supplementary steel balls
- Advantages: Handles variable feed, reduces pebble generation
- Common for primary grinding in large plants
Ball Mills:
- Use steel balls as grinding media
- Closed circuit with hydrocyclones
- Produces fine product (-75 to -150 microns)
- Common for secondary/tertiary grinding
Crushing and Grinding Circuit Design
Classification with Hydrocyclones
- Hydrocyclones separate particles by size and density
- Overflow: Fine particles reporting to flotation
- Underflow: Coarse particles returning to mill
- Cyclone diameter and pressure affect cut point
Optimization Strategies
- Operate crushers at maximum practical reduction ratio
- Use pre-screening to remove fines before secondary crushing
- Optimize grind size based on liberation requirements
- Balance throughput with product quality
- Monitor power draw as indicator of mill fill level
WSHT provides complete comminution circuit design, equipment supply and optimization services for mineral processing applications.
