GLOSSARY - TECHNOLOGY - Multotec · Minerals Engineering ... or very fine ferrosilicon in water for higher density operations such as for diamonds, iron ore, chromites, manganese

GLOSSARY - TECHNOLOGY

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Metallurgy

The science of ore processing and metals


Minerals Engineering

The first major step in extracting metals. Involves the

separation and concentration of minerals from ores using

mainly physical processes.

Often referred to as

Mineral Dressing or Ore Dressing.


Extractive Metallurgy

Follows Ore Dressing.

Includes Pyrometallurgy, Hydrometallurgy, Electrometallurgy

for:

• the removal of remaining waste,

• the decomposition of the metallic mineral to produce metal

• the subsequent refining of metal.


Hydrometallurgy

Uses liquid chemical solutions, treated resins and organics to

separate and concentrate metals by processes such as acid,

alkaline and pressure leaching, ion exchange, solvent

extraction, molecular recognition, precipitation,

crystallization.


Pyrometallurgy

Uses high temperatures for smelting and refining reactions

and melting, pouring, casting and solidification processes.

Pyrometallurgy involves removing impurities from metals by

introducing air and fluxes into the molten metal. The

impurities are removed as gases or slag.


Electrometallurgy Uses electrical energy, principally for electrolysis or

electrowinning to extract and refine metals.


Beneficiation

Treatment of a crude ore in order to improve it’s quality.

Example: beneficiating raw coal to a steam coal for power

generation or to a coking coal for furnaces.


Freeing of valuable minerals /

metals in an ore or mineral by

crushing and grinding.

Liberation

Well Liberated Minerals

Poorly Liberated Minerals


Plant

Facility for processing ores or gravels. A plant where ore is

milled, usually to fine powder, and the valuable metals are

extracted by physical and/or chemical processes.


Run-of-Mine Ore

Uncrushed ore in its natural state just as it is when blasted.

Ore, as accepted for treatment from the Mine.


Gangue

Waste rock that surrounds an ore deposit.

The waste material in an ore.

The valueless tailings/waste fraction of an ore rejected by a

separating process.


Feedrate / Throughput

Capacity of any section of a Plant in terms of tons treated in

a given period e.g. tons per hour for coal, tons per month for

gold.


Recovery

Indicates the proportion of valuable material acquired

from the processing of an ore.

Generally stated as a percentage of the values recovered

compared to the total values present.


Tailings

The neutralised waste discarded after the economically

recoverable metals have been extracted from the ore.


TECHNOLOGIES


How to extract the needle from the haystack


Metallurgical Approaches

Minerals Processing Engineer: Run the entire haystack

through a magnet to retrieve the needle

Pyrometallurgist: Burn the haystack down to find the needle

in the ashes

Hydrometallurgist: Chop up haystack, dissolve it all with

chemicals, plate out metal of the needle


Mineral Product

Metal Product

Run-of-Mine Ore

PREPARATION & SIZING

MINERALS SEPARATION

METALS EXTRACTION

METALS PURIFICATION

METAL PRODUCTION


Minerals Engineering

The first major step in the extraction of metals, this involves

the separation and concentration of minerals from ores using

primarily physical processes.

Often referred to as

Mineral Dressing or Ore Dressing.


Screening

Sizing separation of ore particles into defined size ranges

(fractions).


Gravity Separation

Recovery of values from crushed rock or gravel using

specific gravity differences to separate them.


Jigging

The vertical pulsing of a mass of particles dry, or in water, to

assist the separation of heavy and light ore particles.

Equipment for recovering heavy minerals by gravity settling

through a vibrating screen covered with a ragging bed.

Jig


DMS

Dense Media Separation, in which lighter density ore

particles (floats) separate from heavier particles (sinks) in an

artificial or organic liquid (medium) of intermediate density.

Industrially, the medium is very fine magnetite mixed in

water for coal separations or very fine ferrosilicon in water for

higher density operations such as for diamonds, iron ore,

chromites, manganese ores.


Magnetic Separator

Uses a strong permanent or electro-magnetic field to extract

ferro-magnetic materials from para-magnetic or dia-magnetic

sands or concentrates.


Comminution

Particle size reduction, the crushing of coarse ore

or grinding/milling of fine ore by impact, abrasion, attrition or

compression.


Autogenous Milling

In milling, selectively sized lumps of ore are used as the

grinding media.


Semi-Autogenous Milling (SAG)

Grinding/milling of rock to fine powder in which the grinding

media (charge) consists of larger pieces of rock and steel

balls.


A steel cylinder loaded with

steel balls into which crushed

ore is fed.

The ball mill is rotated, causing

the balls to roll and fall and

grind the ore.

Ball Mill


Cyclone

Hydrocyclone: a centrifugal classifier continuously

separating particles in a water slurry on their size, shape and

density characteristics.

Dense Media Cyclone: a similar vessel with critical

differences which uses an artificial high density medium to

assist density separation.


Flotation

A process for concentrating minerals in milled ores, which

uses the selective adhesion of certain minerals to air bubbles

in water after treatment with chemicals.

The right chemicals with air are added to a stirred ground ore

slurry so the minerals will float to the surface. The metal-rich

flotation concentrate is then skimmed off the surface.


Electrostatic Separator

Separates mineral particles according to retained static

electrical charges induced on them by a high voltage field

with the heavy mineral concentrates deflected by an

electrode.


Thickener

A high capacity solid/liquid separation device. A large circular

tank, often fitted with moving rakes, in which solids settle

slowly to form a high density slurry for continuous removal

from below, while clear water overflows the tank.


Extractive Metallurgy

Follows Minerals Engineering/Ore Dressing.

Includes Pyrometallurgy, Hydrometallurgy, Electrometallurgy

for:

• the removal of any remaining waste,

• the decomposition of the metallic mineral to produce a

metal

• the subsequent refining of the metal.

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GLOSSARY - TECHNOLOGY - Multotec · Minerals Engineering ... or very fine ferrosilicon in water for higher density operations such as for diamonds, iron ore, chromites, manganese