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Hydrometallurgy

Carbon Advance & Loading Calculator

This calculator computes carbon loading as the circuit gold-capture rate divided by the carbon advance rate (a steady-state mass balance), with the gold captured taken as the solution flow multiplied by the feed-minus-barren gold tenor.

In a carbon-in-leach or carbon-in-pulp circuit the gold the circuit captures from solution leaves on the carbon advancing counter-current to the pulp, and at steady state those two rates are equal. This calculator runs that mass balance: it takes the gold captured as the solution flow times the feed-minus-barren gold tenor, divides by the carbon advance rate to get the loading the balance requires, and — when a carbon inventory is supplied — estimates the gold locked up in the circuit. It is a steady-state mass balance only: it does NOT model adsorption kinetics, equilibrium capacity, or whether the stated advance rate achieves the stated barren.

TypeInteractive engineering calculator

Calculator

m³/h

combined solids + liquid flow through adsorption

g/m³

gold-in-solution entering adsorption (g/m³ ≡ mg/L)

g/m³

gold-in-solution leaving adsorption

kg/day

mass of carbon moved against the pulp per day

Optional

kg

contextual — for the gold lock-up estimate

Result
Gold captured rate2088 g/h
Gold captured rate50112 g/day
Carbon loading required6264 g/t
Gold locked in circuit338.256 kg
  • !Steady-state mass balance only — the loading shown is the loading the balance REQUIRES for the advance rate you entered, not a predicted or achievable loading. Whether the carbon reaches it depends on isotherm, kinetics and contact. Confirm against metallurgical testwork.

Formulas

Gold captured rate
Au_rate = Q × (C_feed − C_barren)
Carbon loading required
Loading = Au_rate / M_advance
Gold locked in circuit
Au_locked = M_inventory × Loading

Diagram

Carbon advance & loading — loading = Q(C_feed − C_barren) / M_advancefeed C_feedstage 1stage 2stage 3carbon advance ← M_advancebarrenloading = Q(C_feed − C_barren) / M_advancemass balance — the loading the circuit requires, not predicts

Worked example

A CIL circuit (the eight-tank, 600 m³/h train from the CIL residence-time example, holding ~54,000 kg of carbon) treats solution entering adsorption at 3.5 g/m³ gold and leaving at a barren 0.02 g/m³, with carbon advanced at 8000 kg/day. Find the loading the balance requires and the gold locked up.

  1. 01Gold captured rate: Au_rate = 600 × (3.5 − 0.02) = 600 × 3.48 = 2088 g/h
  2. 02Per day: 2088 × 24 = 50,112 g/day
  3. 03Carbon loading required: 50,112 g/day ÷ 8000 kg/day = 50,112 × 1000 / 8000 = 6264 g/t
  4. 04Gold locked in circuit: 54,000 kg × 6264 g/t ÷ 1,000,000 = 338.256 kg
Result

Gold captured 2088 g/h (50,112 g/day), carbon loading required ≈ 6264 g Au/t carbon, gold locked in circuit ≈ 338 kg. The loading sits in the realistic loaded-carbon range; it is the loading the mass balance requires, not a predicted or achievable value.

FAQ

Does this predict the loading my carbon will reach?
No. It gives the loading the circuit mass balance requires for the advance rate you enter — the gold captured divided by the carbon advanced. Whether the carbon actually reaches that loading depends on the adsorption isotherm, kinetics, and contact, which come from testwork, not from this balance.
How does this differ from the CIL residence-time tool?
The CIL residence-time tool sizes the tankage by residence time and gives an order-of-magnitude carbon mass from a carbon concentration. This tool takes the gold balance — flow and feed-minus-barren tenor against the carbon advance rate — and returns the advance-rate-versus-loading relationship the circuit requires.
Should I use slurry flow or solution flow for Q?
Use the same flow the CIL residence-time tool uses — the solution / slurry flow through adsorption. The balance pairs that flow with the gold-in-solution tenors entering and leaving, so the captured rate is the soluble gold the circuit removes.
Is the gold lock-up a design figure?
No. It is an indicative estimate that applies the computed loading across the whole carbon inventory as a representative average. Real loading varies along the train — loaded carbon at the feed end, barren carbon at the tail — so the true lock-up comes from a loading profile, not a single average.

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