Shanghai DM Crusher
Home › News › Crushing Circuits for Metal Ores: What Changes Compared With Aggregate
Metal-ore crushing exists to feed a mill, not to make a saleable product. That single difference changes how the circuit is staged and what it is measured on.
12 Nov 2024
In an aggregate plant the crusher produces the product, and the product is judged by its size and shape. In a metal-ore circuit the crusher produces the mill feed, and it is judged by how cheaply the grinding stage can then be run. Grinding consumes far more energy than crushing per tonne reduced, so the economics of the whole plant are decided by how fine the crushing circuit can deliver material to the mill.
That is what makes staged crushing worth the extra equipment. Breaking rock by compression in a jaw or cone is far more energy-efficient than grinding it, so every reduction stage completed before the mill is a saving. The practical limit is that each stage has a minimum setting below which it stops performing, which is why the circuit is usually staged: a jaw for the coarse reduction, one or two cone stages for the intermediate work, and a fine cone or a high-pressure stage where the ore allows it.
Ore properties decide how far that can be taken. Hardness and abrasiveness set the wear cost of each additional stage, and the ore texture decides whether the material breaks cleanly or tends to pack. A competent flowsheet is therefore not the one with the most stages, but the one that puts the reduction where it is cheapest for that particular ore. The measurements worth taking before designing anything are the size distribution of the blasted ore, the work index or its practical equivalent, the moisture, and the target feed size the mill actually needs - because a circuit designed without a stated mill feed target cannot be evaluated afterwards.
Tel / WhatsApp: +86 18616330128 | E-mail: ensaichen@dmcrusher.com