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Hydrometallurgy

Flocculant Make-down Calculator

Flocculant make-down is the preparation of a dilute polymer solution that is then dosed into a thickener or clarifier feed. This calculator estimates the dry polymer consumption (kg/h and kg/day), the make-down solution flow (L/h and m³/h), and an approximate solution mass flow, working from the dry solids feed rate, a flocculant dose in g/t, and the make-down solution concentration in g/L. It is a preliminary make-down and dosing estimate only. It is NOT a thickener performance guarantee, a settling test, or a polymer selection tool, and it does not model flocculant aging, maturation, shear degradation, or underflow rheology.

TypeInteractive engineering calculator

Calculator

t/h

dry solids basis

g/t

grams dry polymer per tonne dry solids

g/L

active polymer concentration of the made-down solution

h/day

0–24 h/day

Optional

kg/m³

make-down solution density (default 1000)

Result
Dry polymer consumption3.75 kg/h
Dry polymer consumption90 kg/day
Make-down solution flow1500 L/h
Make-down solution flow1.5 m³/h
Solution mass flow1500 kg/h
  • !Preliminary make-down and dosing estimate only — this is NOT a thickener performance guarantee, settling test, or polymer selection tool.

Formulas

Polymer consumption
ṁ_poly,g/h = ṁ_solids × dose
Polymer consumption (kg/h)
ṁ_poly = ṁ_poly,g/h / 1000
Daily polymer
m_poly,day = ṁ_poly × hours_per_day
Make-down solution flow
Q_sol,L/h = ṁ_poly,g/h / C_solution
Solution flow (m³/h)
Q_sol = Q_sol,L/h / 1000
Solution mass flow
ṁ_sol = Q_sol × ρ_solution

Diagram

Flocculant make-down — dose g/t and make-down g/L set polymer and solution flowpolymerg/tmake-downg/LL/hthickenerpolymer = solids × dose ; flow = polymer ÷ g/Ldosing estimate — not thickener performance

Worked example

A thickener feed carries 150 t/h dry solids dosed at 25 g/t flocculant. The make-down solution is 2.5 g/L, the circuit runs 24 h/day, and the solution density is 1000 kg/m³.

  1. 01Polymer consumption: 150 × 25 = 3750 g/h → 3.75 kg/h
  2. 02Daily polymer: 3.75 × 24 = 90 kg/day
  3. 03Make-down solution flow: 3750 / 2.5 = 1500 L/h
  4. 04Make-down solution flow: 1500 / 1000 = 1.50 m³/h
  5. 05Solution mass flow: 1.50 × 1000 = 1500 kg/h
Result

Polymer 3.75 kg/h (90 kg/day), make-down flow 1500 L/h (1.50 m³/h), solution mass flow 1500 kg/h.

FAQ

Does this guarantee thickener performance?
No. It estimates the polymer consumption and make-down solution flow for a target dose and concentration. Settling rate, underflow density, and overflow clarity depend on settling testwork, polymer selection, and vendor data.
What is the difference between the dose and the solution concentration?
The dose (g/t) is how much dry polymer is added per tonne of solids; the make-down concentration (g/L) is how dilute the prepared solution is. The dose sets polymer consumption; the concentration sets the solution flow needed to deliver it.
Why does the make-down concentration matter?
For a fixed polymer consumption, a more dilute make-down means a larger solution flow to deliver the same mass of polymer. The concentration therefore drives the make-down and dosing flow, not the polymer mass.
What does this calculator deliberately not do?
It does not model flocculant aging or maturation, shear degradation, mixing energy, dilution water quality, dosing control, or underflow rheology, and it is not a settling test or polymer selection tool. Those require vendor data and site testwork.

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