Energy efficiency

Simple energy efficiency is about media size. Smaller media has more surface area and higher media/particle collision frequency making it more efficient.

The high intensity in the IsaMill™ means small media can break coarse particles. The large scale of the IsaMill™ makes that efficiency available to mainstream grinding.

The high energy efficiency of stirred mills compared to ball mills is well understood. The use of tower mills as an energy efficient alternative to secondary and regrind ball milling became a common inclusion in the latter part of the previous century.

Traditionally, the higher energy efficiency was attributed to the difference between attrition grinding in tower mills and impact grinding in ball milling. However, the most important factor for fine grinding is media size and therefore the breakage rate.

Small media has a larger surface area, which translates to better transfer of energy. Although Tower Mills are full attrition grinding, they are constrained to using relatively coarse media 12 to 25mm balls. In contrast, the IsaMill™ can operate with much finer media (e.g. 1mm) and much higher intensity of power input.


Power intensity

Media size

No balls
(per m3)

Surface area

Ball Mill





Tower Mill











Table best viewed in landscape

Media selection has a major influence on mill parameters such as energy efficiency, internal wear and operating costs. With the introduction of economic ceramic media, the energy efficiency of IsaMill™ increases dramatically.​

Comminution consumes 14% of all electricity generated in Australia, and up to 4% world-wide

Fuerstenau, Berkeley University, 2003

and it is "responsible for 50% of total mineral processing costs".

Wills, 1992

… the problem of inefficient use of energy in comminution was so serious that new technology that makes possible comminution to minus 200 mesh (74 micron) at half the energy requirement of conventional mills would justify a Nobel prize for service to mankind.

Alban Lynch and Don McKee, 1981