Metalurgia Del Oro

The Intec Gold Process
by

John Moyes, Technical Director, Intec Geoff Richmond, Manager, Burnie Research Laboratory
Intec Group

The Intec Gold Process (IGP)

Intec Group

One third ofthe world’s gold production is currently sourced from deposits classed as refractory Gold production sourced from refractory deposits can only increase as near-surface oxidised orebodies are depleted‘Single’ refractory deposits predominate however significant ‘double’ refractory deposits also exist
Intec Group

Key Process Features of IGP
Mixed halide leach Single stage co-current Atmosphericpressure & moderate temperature Refractory gold minerals (e.g. arsenopyrite, tellurides and pyrite) leached with air Iron precipitated as hematite (no jarosite) Sulfate precipitated as anhydrite
IntecGroup

Key Process Features of IGP (con’t)
Arsenic precipitated as crystalline scorodite (>100x more stable than amorphous) 90-95oC Fe/As 1:1 seeding
Intec Group

IGP Flow Diagram
GoldConcentrate Limestone Water
S L

SINGLE-STAGE LEACH
Air

Leach Residue

GOLD RECOVERY Activated Carbon
Activated Carbon Column

Gold Dore

IMPURITY BLEED Copper Recovery Plus pH9 PrecipitationLimestone
L S

Lime
L S

By-Product (Zn, Pb, Ni, Cd, Mn,Mg)

Copper Recovery

pH9 Precipitation

Intec Group

IGP Arsenopyrite Leach Chemistry
FeAsS + 2O2 FeAsO4 + S 2Cu2+ + H2OH3AsO4 + Fe2+ + S + 5H+ + 7Cu+

2Cu+ + 1/2O2 + 2H+ FeAsS + 7Cu2+ + 4H2O Cu2+ + Fe2+ H3AsO4 + Fe3+ 3Cu2+ + Au + 4Br-

Cu+ + Fe3+ FeAsO4 + 3H+ AuBr4- + 3Cu+

Intec Group

IGP Pyrite LeachChemistry

4FeS2 + 15O2 + 2H2O 2Cu+ + 1/2O2 + 2H+ FeS2 +15Cu2+ + 8H2O Cu2+ + Fe2+

8SO42- + 4Fe3+ + 4H+ 2Cu2+ + H2O 2SO42- + Fe3+ + 15Cu+ + 16H+

Cu+ + Fe3+ AuBr4- + 3Cu

3Cu2+ + Au + 4Br-

IntecGroup

IGP Iron & Sulfate Control

2Fe3+ + 3H2O

Fe2O3 + 6H+ CaSO4 + H2O + CO2

SO42- + 2H+ + CaCO3

Intec Group

IGP Materials of Construction
FRP for tanks & pipes

Titanium for...