A novel pseudo-Gemini collector (PGC) featuring pH-responsive collecting power and enhanced selectivity is developed for flotation recovery of fine copper oxides from silica. The switchable PGC is formed through ionic pairing between protonated triethylenetetramine (TETA) and deprotonated oleic acid (OA) and is referred to as T-OA. The formation of T-OA was characterized by determining its critical micelle concentration of 0.6 mM at pH 10, which is much lower than that of 2.5 mM for its counterpart of OA, demonstrating a stronger surface activity of the novel T-OA collector for hemimicelle formation. Micro-flotation results showed a CuO recovery of over 90% at T-OA concentrations as low as 0.01 mM and pH 10, at which the collector exists in pseudo-Gemini form. Adjusting the flotation pH to 5 switched T-OA to monomeric form of OA with a lower surface activity but a higher selectivity which was further improved by removal of activating ions from silica by TETA. Introducing T-OA of higher collecting power in the rougher stage and then switching to a lower collecting power form of higher selectivity in the subsequent cleaner stage enhanced the flotation separation of fine CuO from silica. Zeta potential measurements indicated adsorption of T-OA on copper oxide at pH 5 and 10 with the hydrophobicity of copper oxide being stronger at alkaline conditions than that at acidic conditions as determined by contact angle measurement. The switchability of T-OA activity on CuO surfaces was illustrated by contact angle and in situ particle size distribution measurements. The reversible adsorption of T-OA on copper oxide at pH 10 was shown by QCM-D results. The results in the current study using switchable T-OA provide a clear direction for design of switchable collectors to achieve the control of the collecting performance and selectivity during the flotation processes, enhanced overall flotation performance.

开发了一种新型伪双子捕收剂 (PGC)，其具有 pH 响应捕收能力和增强的选择性，用于从二氧化硅中浮选回收细小的氧化铜。可切换的 PGC 是通过质子化三亚乙基四胺 (TETA) 和去质子化油酸 (OA) 之间的离子配对形成的，被称​​为 T-OA。通过确定其在 pH 10 下的临界胶束浓度为 0.6 mM 来表征 T-OA 的形成，这远低于其对应的 OA 的 2.5 mM，表明新型 T-OA 半胶束捕收剂具有更强的表面活性形成。微浮选结果显示，在低至 0.01 mM 和 pH 10 的 T-OA 浓度下，CuO 回收率超过 90%，此时捕收剂以假双子形式存在。将浮选 pH 值调整为 5 将 T-OA 转换为具有较低表面活性但较高选择性的 OA 单体形式，通过 TETA 从二氧化硅中去除活化离子进一步提高选择性。在粗选阶段引入更高捕集能力的 T-OA，然后在随后的清洁阶段切换到更高选择性的较低捕集能力形式，增强了细 CuO 与二氧化硅的浮选分离。Zeta 电位测量表明 T-OA 在 pH 5 和 10 下吸附在氧化铜上，氧化铜的疏水性在碱性条件下比在酸性条件下更强，这是通过接触角测量确定的。T-OA 活性在 CuO 表面上的可切换性通过接触角和原位粒度分布测量来说明。QCM-D 结果显示了 T-OA 在 pH 10 下对氧化铜的可逆吸附。目前使用可切换T-OA的研究结果为可切换捕收剂的设计提供了明确的方向，以实现浮选过程中捕收性能和选择性的控制，提高整体浮选性能。