Ore Concentration

comminution · flotation · dewatering · concentrate

A copper mine moves about 200 tons of rock for every ton of copper it ships. Grinding that rock is the largest electrical load at most mine sites, and it is already electric.

Three concentration flows showing grade at each step. Copper: ore about 0.5% Cu, flotation concentrate 25 to 30% Cu, refined cathode 99.99% Cu. Lithium from hard rock: spodumene ore 1 to 1.5% Li2O, SC6 concentrate 6% Li2O, battery-grade hydroxide. Rare earths: bastnaesite ore about 6 to 8% rare earth oxide, concentrate about 60%, separated NdPr oxide 99% plus. Crushing, grinding, flotation and separation are electric; the final refining step is chemistry. GRADE AT EACH STEP: CONCENTRATION REJECTS MOST OF THE MASS Copper Ore ~0.5% Cu Concentrate 25-30% Cu Cathode 99.99% Cu Lithium (hard rock) Spodumene ore 1-1.5% Li2O SC6 concentrate 6% Li2O Hydroxide battery grade Rare earths Bastnaesite ore ~6-8% REO Concentrate ~60% REO Separated oxide NdPr 99%+ Grinding, flotation and separation are electric; the last step is chemistry.
Copper ore grade
~0.5%
Lithium SC6 grade
6% Li2O
Largest mill drives
Gearless, 20+ MW
Hub
Industry

Finding

Beneficiation is the most electrified step in mining, and the remaining gains are in grinding efficiency and in replacing gas-fired concentrate dryers

Crushers, SAG and ball mills, flotation cells, pumps and magnetic separators all run on electric motors; the biggest semi-autogenous (SAG) mills reach 40 feet in diameter on gearless ring-motor drives above 20 MW from ABB and Siemens. Comminution typically takes around half of a mine site's energy, almost all of it as electricity.

Because the process is already electric, decarbonizing it means cleaner power and less of it. High-pressure grinding rolls (HPGR) from Weir, FLSmidth and Metso cut grinding energy against SAG circuits; sensor-based ore sorting from TOMRA and Steinert rejects waste rock before it reaches the mill; coarse-particle flotation (Eriez HydroFloat) lets ore be ground less finely. Chinese suppliers CITIC Heavy Industries (mills) and BGRIMM (flotation cells) equip most Chinese concentrators and a growing share of African and Latin American projects.

Dewatering and drying are where fuel remains. Thickeners, filter presses and centrifuges are electric, but final concentrate and some lithium and mineral sands dryers still burn gas or diesel; electric rotary, microwave and heat-pump dryers and electro-osmotic dewatering are replacing them, with electro-osmosis still at pilot scale. In Texas, the Round Top rare earth deposit near El Paso is on AustinIO.

Process

The electrified process chain

Every step from crusher to filter press is motor-driven; grinding is the largest load.

Ore beneficiation steps
StepEquipmentRoleElectrification note
CrushingJaw, gyratory and cone crushersBreaks run-of-mine oreLarge induction motors; some in-pit crushers replace diesel haul trucks with conveyors
GrindingSAG, ball and vertical mills, HPGRLiberates mineral grainsLargest site load; gearless drives over 20 MW; HPGR saves energy
Ore sortingX-ray, laser and near-IR sortersRejects waste before grindingCuts mill energy per ton of metal
ClassificationHydrocyclones, screensSplits by particle sizeSlurry pumps on variable-speed drives
Magnetic and gravity separationMagnetic drums, spirals, jigsConcentrates magnetite, mineral sands, heavy mineralsContinuous and fully electric
FlotationTank cells, agitators, blowersSeparates by surface chemistryAgitators and air blowers; cells now exceed 600 cubic meters
DewateringThickeners, filter presses, centrifugesRemoves water for transportElectric; recovers process water
DryingRotary, microwave and heat-pump dryersRemoves residual moistureLast step still often fired by gas or diesel

Commodities

Concentration by commodity

Flowsheets differ by mineral; battery metals add steps that base metals do not need.

Beneficiation by commodity
CommodityFlowsheetNotable operationsNotes
CopperCrush, grind, flotationEscondida (BHP), Grasberg (Freeport), Kamoa-Kakula (Ivanhoe, Zijin)Ore grades declining, so more rock ground per ton of copper
Iron ore (magnetite)Grind, magnetic separationMinnesota Iron Range, Sino Iron (CITIC Pacific)Very fine grinding for DRI-grade pellet feed
Lithium (spodumene)Dense media separation, flotation to SC6Greenbushes (Talison: Tianqi, IGO, Albemarle), Pilgangoora (Pilbara Minerals)Concentrate shipped mostly to China for conversion
Nickel (sulfide)Grind, flotationNorilsk (Nornickel), Sudbury (Vale)Indonesian laterite skips flotation and goes to HPAL or smelting
Rare earthsGrind, flotation, sometimes magneticBayan Obo (China Northern Rare Earth), Mountain Pass (MP Materials)Bastnaesite flotation to about 60% REO
Tailings reprocessingRegrind, flotation, dewateringCopper and gold tailings projectsDriven by water reuse and tailings rules

Sources

Sources and scope

Scope
Ore Beneficiation and Concentration
Sources
Operator disclosures (BHP, Freeport, Pilbara Minerals, MP Materials); ABB and Siemens mill-drive references; CEEC comminution data
Updated
October 2026