Nickel Laterite HPAL: 2D Autoclave Compartments

Autoclave

Temperature 250 C

Acid dose 380 kg/t

Total residence time 80 min

Slurry solids 30%

Ore Mg content 3.0%

Discharge

Ni extraction

-

Free acid

-

Fe to hematite

-

Fe left dissolved

-

Total pressure

-

Net acid use

-

Steam

-

Mg dissolved

-

Status

-

Each compartment is a CSTR: dX/dt = k(T,[H2SO4])(1-X) + (X_prev - X)/tau. Fe dissolves (1.5 H2SO4 per Fe) and hydrolyses to hematite above ~240 C, regenerating acid. Mg, Al consume acid. P = P_sat(T) + 0.3 MPa.