Use of amino acids for gold dissolution

As oxidants under alkaline conditions. To analyze the kinetics of leaching, tests were performed using electrical contacts pins and sheets of pure gold to avoid the effects of pore diffusion. The efficiency of each oxidant was evaluated, for concentrations of 0.004, 0.01 and 0.03 M, at pH values of 9.4 and 11. At the end of each test, the solid residue was analyzed to determine the total grade and percentage of metal extraction. The experimental results indicated that the percentage of gold extraction was affected by the oxidant concentration and the pH. Furthermore, it improves with the presence of Cu2+ ions, increasing by 100% for glycine and approximately 6 fold for glutamate as compared to glycine solutions. In assessing the percentage of gold extraction in the different conditions at 25 and 40 °C, it was observed that the kinetics of extraction is sensitive to temperature change, which suggests that the leach is chemically controlled.