The Final Word on Fines
The generation of fines also depends on the type of crushers and feed rates being used. Impact crushers generally produce more fines (perhaps as much as 25 to 30 percent) than compressive crushers (jaw and cone crushers). Feed rates resulting in rock-on-rock interaction in an impact crusher commonly generate more fines than rock-on-metal interaction. But keep in mind, rock-on-metal interactions cause high wear of crusher components and create different particle shapes than rock-on-rock interactions.
Storage of fines affects the final use. Fines have a very large surface area in relation to the particle size, and the increased surface area sometimes facilitates weathering and chemical alterations to stockpiled material. Fines stored in stockpiles are exposed to the air and may weather differently than those stored in settling ponds. Fines stored in settling ponds are also more difficult to handle and ship than fines that are stored dry. The good news is that, in some situations, fines can be dredged from settling ponds and dried in specially constructed drainage cells, thus allowing them to compete for markets commonly thought only available to dry-stored fines.
I think this stuff is fascinating, but if I bored you with this story about fines, you have my wife to thank. She allowed it — this time.
Author’s Note: Thanks to Terry Lee, of Florida Environmental Dredging, for information on dredging fines from settling ponds.
Uses of fines from A to Z