Comminution

fergusonite should part on its domain walls new section comminution and liberation comminution is the engineering word for crushing and grinding reducing the size of a solid so that its components can be separated liberation is the result that matters the fraction of the valuable phase that ends up in particles consisting only of that phase This section introduces the vocabulary, the empirical laws, the single-particle mechanics, and the models of this field, with an eye to what an atomistic model could feed into them.

Machines, stresses and energy.

Comminution runs from coarse to fine.

Jaw and cone crushers with size reduction ratios of 5 to 10 per stage.

High pressure grinding rolls that crush a confined bed of particles between two rolls at 50 to 300 MPa, and then tumbling or stirred mills in which balls or beads hit and rub the particles.

Compression between surfaces loads a particle like a Brazilian disc, in indirect tension across its middle, whereas attrition chips its corners.

The energy needed to grind is enormous.

Comminution consumes a few percent of the world's electricity and about half of the electricity of a typical mine, and only one to two percent of that energy ends up as new surface.