kilowatt-hour per tonne
Specific energyexact by definition
One kilowatt-hour per tonne, equal to 3.6 kJ/kg exactly. It is the unit of comminution — crushing and grinding — and the unit Bond's work index is universally quoted in.
Watch out: A work index is defined by ONE specific standard mill test. A figure from any other test is not interchangeable with it, however similar the units look — the number carries the procedure that produced it.
| 1 | 3,600 |
Mineral processing runs on tonnes and buys electricity in kilowatt-hours, so the unit is the ratio of the two things a concentrator actually meters. Bond's 1952 work index is defined as the kWh/t needed to reduce material from a theoretically infinite size to 80% passing 100 micrometres, which is why the number is a material property rather than a process figure.
One kilowatt-hour per tonne in every specific energy unit
| 3,600 | joule per kilogram (J/kg) | |
| 3.6 | kilojoule per kilogram (kJ/kg) | |
| 0.0036 | megajoule per kilogram (MJ/kg) | |
| 1 | watt-hour per kilogram (Wh/kg) | |
| 0.001 | kilowatt-hour per kilogram (kWh/kg) | |
| 1 | kilowatt-hour per tonne (kWh/t)this unit | |
| 1.54772 | BTU per pound (BTU/lb) | |
| 0.907185 | kilowatt-hour per short ton (kWh/ton) |