Sulfidic copper–lead–zinc tailings can pose a significant environmental threat, ranging from generation of acid mine drainage (AMD) to dam failures. On the other hand, they can also be considered as low-grade ore resources for zinc and copper provided that novel economically feasible metal extraction and metal recovery techniques are developed. Due to the low metal concentrations in these resources, the leaching will generate dilute leachates from which metal recovery is a challenge. Ion flotation is a foam separation technique capable of recovering metal ions from dilute aqueous leachates. In this paper, ion flotation was applied to separate copper from ammoniacal leachates of microwave-roasted sulfidic tailings samples. The sulfidic tailings were first roasted at 550 °C for 60 min, for the oxidation of sulfide minerals to more easily soluble sulfates using microwave-assisted irradiation as heating source. The microwave-roasted material was then leached with a mixture of ammonia and ammonium carbonate solutions. The optimum leaching efficiencies of zinc (86%) and copper (75%) were obtained under the following conditions: liquid-to-solid ratio = 10 mL g⁻¹, T = 90 °C, [NH₃ + NH₄⁺] = 4 mol L⁻¹, NH₃:NH₄⁺ = 2:1, t = 5 h. From the generated pregnant leach solution, it was possible to selectively separate 85% of copper to the foam phase by ion flotation, with sodium dodecyl sulfate (SDS) surfactant, as colloidal copper(II) tetraamine dodecyl sulfate under the optimized conditions: [SDS]_total = 5.85 mmol L⁻¹, [EtOH] = 0.5 % (v/v), t_total = 5 h, flotation stages = 3. The zinc that remained in the solution after ion flotation was recovered by precipitation (95%) as basic zinc carbonate.

Graphical Abstract

Copper and zinc extraction by ammoniacal leaching from microwave-roasted Cu-Zn-Pb sulfidic tailings followed by recovery of copper and zinc by ion flotation and precipitation.

中文翻译：

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离子浮选从氨水渗滤液中回收铜

硫化铜-铅-锌尾矿可能构成严重的环境威胁，其范围从酸性矿山排水（AMD）的产生到大坝的倒塌。另一方面，如果开发了新颖的经济可行的金属提取和金属回收技术，它们也可以被视为锌和铜的低品位矿石资源。由于这些资源中的金属浓度较低，因此浸出将产生稀沥滤液，因此很难从中回收金属。离子浮选是一种泡沫分离技术，能够从稀水浸出液中回收金属离子。本文采用离子浮选法从微波焙烧的硫化尾矿样品中的氨浸出液中分离出铜。首先将硫化尾矿在550°C下烘烤60分钟，微波辅助辐射作为加热源，可将硫化物矿物氧化为更易溶的硫酸盐。然后用氨和碳酸铵溶液的混合物浸出微波烘焙过的材料。在以下条件下可获得锌（86％）和铜（75％）的最佳浸出效率：液固比= 10 mL g^-1，T＝ 90℃，[NH ₃ + NH ₄ ⁺ ] ＝ 4mol L ^-1，NH ₃：NH ₄ ⁺＝ 2∶1，t＝ 5h。在最佳条件下，可以通过十二烷基硫酸钠（SDS）表面​​活性剂通过离子浮选从生成的母体浸出溶液中选择性分离出85％的铜到泡沫相，作为胶体铜（II）四胺十二烷基硫酸盐： ]_总计= 5.85 mmol L ^-1，[EtOH] = 0.5％（v / v），t_总计= 5 h，浮选阶段=3。通过沉淀回收离子浮选后残留在溶液中的锌（95％）作为碱性碳酸锌。

图形概要

通过氨浸法从微波焙烧的Cu-Zn-Pb硫化尾矿中提取铜和锌，然后通过离子浮选和沉淀法回收铜和锌。