Hydrometallurgy Glossary
48 terms across the five process segments — each defined precisely enough to compute with, with its units, its limits and what it is commonly confused with.
Browse alphabetically
Leaching Equipment (7)
Bioleaching
Leaching in which micro-organisms generate the lixiviant or catalyse the dissolution reaction.
GL-LEACHINGLeaching
Dissolving target metals out of an ore, concentrate or residue into an aqueous solution.
GL-PREGNANT-LEACH-SOLUTIONPregnant Leach Solution
The metal-rich solution leaving the leaching step, ready for purification and recovery.
GL-PROCESS-FLOWSHEETProcess Flowsheet
A diagram showing the sequence of process units and the streams connecting them.
GL-PULP-DENSITYPulp Density
The proportion of solids in a slurry, usually expressed as mass percent or grams per litre.
GL-RESIDENCE-TIMEResidence Time
The average time a fluid or slurry spends inside a process unit.
GL-SCALE-UPScale-Up
Translating a process proven at bench or pilot size to production capacity.
Solid-Liquid Separation (7)
Cake Filtration
Filtration in which solids build a permeable cake that itself becomes the filtering medium.
GL-CAKE-MOISTURECake Moisture
The mass fraction of liquid remaining in a filter cake after discharge.
GL-CLARIFICATION-RATEClarification Rate
The upward liquid velocity a settling device can sustain while still producing a clear overflow.
GL-FILTER-AIDFilter Aid
A fine, rigid powder added to a slurry or precoated on a medium to keep filtration flowing.
GL-FILTER-PRESSFilter Press
A batch pressure filter that pumps slurry into a stack of clamped plates to form cakes between them.
GL-FLOCCULATIONFlocculation
Agglomerating fine particles into larger, faster-settling flocs using a polymer or coagulant.
GL-SOLID-LIQUID-SEPARATIONSolid-Liquid Separation
The family of operations that divide a slurry into a clear liquid and a concentrated solids stream.
Liquid-Liquid Separation (Solvent Extraction) (22)
Centrifugal Extractor
A contactor that uses centrifugal force instead of gravity to mix and separate two phases in seconds.
GL-CRUDCrud
A stable emulsion layer of fine solids that accumulates at the organic-aqueous interface.
GL-DILUENTDiluent
The inert organic liquid that carries the extractant and moderates the organic phase's physical properties.
GL-DISTRIBUTION-COEFFICIENTDistribution Coefficient
The ratio of a metal's total concentration in the organic phase to that in the aqueous phase at equilibrium.
GL-ENTRAINMENTEntrainment
Droplets of one phase carried out of a settler with the other phase.
GL-EXTRACTANTExtractant
The active organic-phase reagent that selectively binds and carries the target metal.
GL-EXTRACTION-ISOTHERMExtraction Isotherm
A plot of organic-phase metal concentration against aqueous-phase concentration at equilibrium.
GL-HETSHETS
The height of column packing or internals that performs the same separation as one ideal stage.
GL-ION-EXCHANGEIon Exchange
A separation process in which dissolved ions swap places with ions held on a solid resin.
GL-MCCABE-THIELE-DIAGRAMMcCabe-Thiele Diagram
A graphical method that steps between an operating line and the equilibrium isotherm to count theoretical stages.
GL-MIXER-SETTLERMixer-Settler
A contactor that repeats one discrete extraction stage: mix to transfer mass, then settle to separate the phases.
GL-O-A-RATIOO/A Ratio
The volumetric flow ratio between the organic and aqueous phases entering a contactor.
GL-PHASE-DISENGAGEMENTPhase Disengagement
The time required for a mixed dispersion to separate back into continuous organic and aqueous layers.
GL-PILOT-PLANTPilot Plant
A scaled-down operating plant used to prove a process before full-scale design is committed.
GL-RAFFINATERaffinate
The aqueous solution left after the target metal has been extracted out of it.
GL-RECOVERYRecovery
The percentage of the metal in the feed that reports to the product stream.
GL-ROTATING-DISC-CONTACTORRotating Disc Contactor
An agitated extraction column in which a central shaft carries discs that shear the phases into droplets.
GL-SCRUBBINGScrubbing
A wash stage that removes co-extracted impurities from the loaded organic before stripping.
GL-SOLVENT-EXTRACTIONSolvent Extraction
A separation technique that transfers a dissolved metal from an aqueous solution into an immiscible organic phase.
GL-STAGE-EFFICIENCYStage Efficiency
The fraction of the theoretical mass transfer that an actual stage achieves.
GL-STRIPPINGStripping
Transferring metal from the loaded organic phase back into an aqueous solution.
GL-THIRD-PHASEThird Phase Formation
An unwanted splitting of the organic phase into a heavy metal-loaded layer and a light layer.
Evaporation & Crystallization (6)
Boiling Point Elevation
The rise in a solution's boiling point above that of pure water at the same pressure, caused by dissolved salts.
GL-CRYSTALLIZATIONCrystallization
Forming solid crystals from solution by supersaturation, usually through evaporation or cooling.
GL-MULTIPLE-EFFECT-EVAPORATIONMultiple-Effect Evaporation
Evaporation arranged so that vapour boiled off one vessel heats the next, reusing the energy repeatedly.
GL-MVRMVR
Recompressing evaporated vapour with a compressor so it can be reused as the heating medium.
GL-SCALING-FOULINGScaling and Fouling
Deposit build-up on heat transfer surfaces that steadily reduces capacity.
GL-STEAM-ECONOMYSteam Economy
Kilograms of water evaporated per kilogram of steam consumed.
Electrolysis & Electrowinning (6)
Cathode Plate
The electrode on which metal is deposited in an electrowinning cell.
GL-CELL-VOLTAGECell Voltage
The total voltage across an electrowinning cell, being the sum of all the potentials and resistances in the circuit.
GL-CURRENT-DENSITYCurrent Density
The current applied per unit of cathode area, usually quoted in amperes per square metre.
GL-CURRENT-EFFICIENCYCurrent Efficiency
The share of the applied current that actually produces the desired metal deposit.
GL-ELECTROWINNINGElectrowinning
Recovering a metal from solution by passing current through it so the metal deposits on the cathode.
GL-FARADAYS-LAWFaraday's Law
The rule that the mass of metal deposited is proportional to the charge passed.
A–Z index
B
C
D
E
F
H
I
L
M
O
P
R
S
T
Sizing equipment around these parameters?
Send feed material, throughput and medium — an engineer replies with a preliminary configuration and the sizing calculation behind it.