Impact crushing has been used in the construction industry/quarrying business for decades, but has never found much acceptance or application in the minerals processing industry, due to perceived high downtime and wear parts consumption. Although this is true, most crushing operations have high downtime, and ultimately grinding media consumption in IC crushing is generally no more than (and often less than) conventional circuits.
Impact crushing has further benefits of extremely high reduction ratios – often more than 50/1 – and preferential fracture of mineral ores.
Many minerals – most notably quartz-hosted free gold – will shatter on weak mineral planes when subjected to extreme impact, and it is these weak planes that host the gold. Impact crushing can therefore often provide extremely good liberation and recovery at relatively large particle size. This applies not only to free gold, but also to a host of base and industrial minerals.
Whilst there is generally a small recovery sacrifice in not grinding the entire ore to “bug dust,” there are 2 huge benefits to this technique:
- Liberation of mineral at as course a size as possible, without over-grinding and rendering concentration (specifically by gravity) more difficult.
- Huge power and grinding media saving by not unnecessarily grinding barren matrix rock.
Peacocke & Simpson has the ability to perform mineral and process testing a variety of impact crushing techniques, and the equipment (including microscope image capture of liberated particles) to determine the efficacy of impacting on any ore.