Zircon Jig Separation: Density-Driven Stratification (2D)

Jig Operation

Pulsation frequency 55 strokes/min

Stroke amplitude 18 mm

Hutch water (up-current) 8 mm/s

Feed

Grain size (Ø) 0.12 mm

Feed zircon fraction 35%

Live Readout

Elapsed time

0.0 s

Stratification

0.0 cm

Concentrate grade

0.0%

Zr recovery

0.0%

How it works

Zircon (ρ ≈ 4650 kg/m³) is roughly 1.75× denser than the quartz sand (ρ ≈ 2650 kg/m³) it is mixed with. Neither can be told apart by size or shape alone — the separation relies entirely on the density difference, exactly as the plant's own name implies. In water (ρ ≈ 1000 kg/m³, viscosity μ ≈ 1.0 mPa·s) each grain has a Stokes settling velocity:

v_t = (2/9) · r² · g · (ρ_particle − ρ_water) / μ

A pulsating water column (frequency × amplitude, as on a real jig) periodically lifts and loosens the bed; between pulses, grains settle at their own v_t. Because zircon's v_t is roughly 2.2× quartz's at the same grain size, it sinks through the loosened bed faster on every cycle — this is differential settling / hindered-bed stratification, the working principle of gravity concentration.

Hutch water — a steady up-current that preferentially carries the slower-settling quartz upward and out, while dense zircon still out-settles it.
Over-agitation — push frequency and amplitude too high and the pulse velocity dominates the settling velocity for both species: the bed re-suspends into a turbulent mix and the grade readout collapses, mirroring a real jig running "too hard."
Grain size — v_t scales with r², so coarser feed stratifies faster but also responds more violently to the same pulse, which is why real jig feeds are screened to a narrow size band before treatment.

Zircon (dense) Quartz (light) Grade-by-depth profile