AARL (Anglo American Research Laboratories) strip is a pressurized variant of carbon desorption used in ADR plants. Loaded carbon is contacted with hot (110–130°C) caustic-cyanide solution under 2–4 bar pressure for 4–8 hours, eluting gold off the carbon faster than atmospheric Zadra strip.
AARL vs Zadra
Speed: AARL strips in 4–8 hours; Zadra takes 24–36 hours. Reagent: AARL uses caustic + cyanide; Zadra uses caustic + cyanide + alcohol (Zadra needs the alcohol; AARL does not). Pressure: AARL is 2–4 bar; Zadra is atmospheric. Equipment cost: AARL strip vessels are pressure vessels — typically more expensive per kilo of carbon capacity.
When to Choose AARL
High-throughput operations where strip cycle time is the production bottleneck — AARL's 4–8 hour cycle lets a smaller strip vessel keep up. Operations where alcohol handling is a safety or regulatory burden. Operations with mature operating teams that can manage pressure-vessel operation.
When to Choose Zadra
Smaller modular plants where capital cost matters most. Remote sites where alcohol resupply is straightforward but specialty pressure-vessel maintenance is not. Operations where simplicity is a primary design objective.
KCA Practice
KCA delivers both. The Zadra approach is standard on our modular ADR plant lineup (Models 20, 30, 50, 150). For high-capacity site-built operations we evaluate AARL vs Zadra economics during the feasibility study. See ADR Plant Design.
Have a project that involves AARL Strip?
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