Abstract
Copper interference remains a critical challenge in gold recovery during carbon‑in‑leach (CIL) operations, leading to increased cyanide consumption and reduced adsorption efficiency. This study investigated the impact of DETA and/or Cu-DETA complex on gold adsorption by activated carbon (AC) during carbon-in-leach (CIL) operations. Gold adsorption by activated carbon and recovery after the CIL process were examined in the absence and presence of both Cu and DETA. The pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models were applied to analyze adsorption behavior under various conditions. The results showed that AC alone adsorbed 98.9% of gold, but Cu²⁺ reduced gold adsorption by 7.8% (from 98.9% to 91.1%), likely due to competitive adsorption. AC adsorbed 91.4% of Cu²⁺ in the absence of DETA, but adsorption dropped significantly when DETA was added, indicating AC’s low affinity for Cu-DETA complexes. The kinetic modeling revealed that the PSO model provided a better fit (R² > 0.99, lower RMSE) for gold adsorption capacity and rate compared to the PFO model, suggesting that chemisorption governs gold adsorption under the study conditions. In the CIL tests, gold recovery decreased from 91.2% to 62.1% with copper sulphate but was restored to 90%-92% with the addition of DETA. These study findings establish DETA as a practical strategy to suppress copper interference, reduce cyanide consumption, and sustain high gold recovery in copper‑rich ores.