ADR stands for Adsorption / Desorption / Recovery — the three-stage carbon-adsorption circuit used to extract gold from pregnant leach solution in heap leach and CIP/CIL operations. KCA has delivered 74 modular ADR plants worldwide, from 15 m³/h container-mounted pilots to 3,200 m³/h site-built systems.
Adsorption (the "A")
Pregnant leach solution flows through a series of columns packed with activated carbon. Gold ions (as gold-cyanide complex) adsorb onto the carbon surface. A typical ADR plant has 4–6 columns operated in countercurrent series, allowing one column to be removed for stripping while the others stay online.
Desorption (the "D")
The loaded carbon is moved to a strip vessel where hot caustic-cyanide-alcohol solution (Zadra strip) or pressurized hot caustic (AARL strip) elutes the gold off the carbon back into solution. Strip times range from 18 to 36 hours depending on configuration.
Recovery (the "R")
The eluted gold-rich strip solution flows to electrowinning cells, where gold plates out onto stainless steel wool cathodes. The loaded cathodes are then sent to the gold room for smelting into doré bars.
Modular vs Site-Built
KCA fabricates four standard modular ADR models (Model 20, 30, 50, 150) for fast-deployment to remote sites — wet-tested in Reno before shipping. For high-capacity operations we build custom site-built ADR circuits. The largest KCA ADR delivered is 3,200 m³/h at Ivrindi, Turkey. Full detail at ADR Plant Design.
Have a project that involves ADR Plant?
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