Calculations
Crusher - Bond's Law | Power and Sizing
Input data
Inlet massic flow
Work index
Product P80 - 80% passing size after crushing
Output data
Input data
Required power
Work index
Product P80 - 80% passing size after crushing
Output data
Input data
Required power
Mass flow inlet
Product P80 - 80% passing size after crushing
Output data
Input data
Required power
Mass flow inlet
Work index
Product P80 - 80% passing size after crushing
Output data
Feed F80 - 80% passing size before crushing
Input data
Required power
Mass flow inlet
Work index
Output data
Description
Calculate grinding parameters using Bond's Law (Fred Bond, 1961), which establishes the relationship between specific energy consumed in material fragmentation and the granulometric characteristics of feed and product.
Crusher
There are 5 calculation possibilities:
- Calculate the required power
- Calculate the mass flow
- Calculate the work index
- Calculate the diameter before crushing (F80)
- Calculate the diameter after crushing (P80)
Bond's Law is expressed by the equation:
Where:
- P = Required power (kW)
- m = Inlet mass flow (ton/h)
- Wi = Work index of material (kWh/ton)
- F80 = 80% passing size before crushing (μm)
- P80 = 80% passing size after crushing (μm)
Input Data
| Parameter | Default Units | Description |
|---|---|---|
| Inlet mass flow | ton/h | Material feed rate to the mill |
| Work index | kWh/ton | Specific energy required to reduce material from theoretically infinite size to 100 μm |
| Feed F80 | mm | Opening size that allows passage of 80% of material before crushing |
| Product P80 | mm | Opening size that allows passage of 80% of material after crushing |
| Required power | kW | Mechanical power needed for the grinding process |
Output Data
| Parameter | Default Units | Description |
|---|---|---|
| Required power | kW | Calculated mechanical power for the process |
| Inlet mass flow | ton/h | Calculated feed rate |
| Work index | kWh/ton | Calculated work index of material |
| Feed P80 | mm | Calculated size before crushing |
| Product F80 | mm | Calculated size after crushing |
Work Index for Different Materials - Wet Grinding
| Material | Wi (kWh/ton) |
|---|---|
| Bauxite | 8.7 |
| Raw cement | 10.51 |
| Clay | 6.30 |
| Coal | 13.00 |
| Granite | 15.13 |
| Wheat | 4.35 |
| Gravel | 16.06 |
| Iron ore (hematite) | 12.84 |
| Phosphate mineral | 9.92 |
| Quartz | 13.57 |
Note: For dry grinding, multiply Wi by 1.33.
References
- BOND, Fred, C. Crushing & Grinding Calculations - Part I. British Chemical Engineering, 1961.