Reprocessing tailings for gold recovery is generating new low-grade refractory secondary tailings. Unlocking gold trapped within these secondary tailings potentially holds additional economic value. In this study, the use of supercritical carbon dioxide (scCO₂) at 100 bar and 40 °C for gold extraction from such a secondary gold tailings sample (0.27 g Au/t) was investigated. The research identified and screened the following ligands as suitable extractants for gold in scCO₂: 3-(trifluoromethyl)-phenyl-thiourea (TPT), 1,1,1-trifluoro-2,4-pentanedione (TFA), betaine bis(trifluoromethylsulfonyl)imide ([Hbet][TF₂N]), 4-methyl-4H-1,2,4-triazole-3-thiol (MHTT) and hexafluoroacetylacetone (HFA). Results from screening experiments showed that extraction of gold for all ligands in the presence of a tri-n-butyl phosphate-nitric acid adduct (TBP-HNO₃) as oxidant exceeded 50% after 18 h, with the highest extraction offered by [Hbet][TF₂N] (82% after 24 h). A comparative study, where no scCO₂ was present, showed that the presence of scCO₂ offered a distinct advantage in extraction.

回收黄金的尾矿后处理正在产生新的低品位耐火二次尾矿。解锁这些二次尾矿中的黄金可能具有额外的经济价值。在本研究中，研究了在 100 bar 和 40 °C 下使用超临界二氧化碳 (scCO ₂ ) 从此类二次金尾矿样品 (0.27 g Au/t) 中提取金的情况。该研究确定并筛选了以下配体作为 scCO _{2 中}金的合适萃取剂：3-(三氟甲基)-苯基硫脲 (TPT)、1,1,1-三氟-2,4-戊二酮 (TFA)、甜菜碱双(三氟甲基磺酰基）亚胺（[Hbet][TF ₂N])、4-甲基-4H-1,2,4-三唑-3-硫醇 (MHTT) 和六氟乙酰丙酮 (HFA)。筛选实验的结果表明，在磷酸三正丁酯 - 硝酸加合物 (TBP-HNO ₃ ) 作为氧化剂存在下，所有配体的金提取率在 18 小时后超过 50%，其中 [Hbet ][TF ₂ N]（24 小时后 82%）。的比较研究中，没有SCCO其中₂存在，表明SCCO的存在₂中萃取提供了明显的优势。