Enhancement of copper mobilization using acidic AlCl3 − rich lixiviant

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering Pub Date : 2024-08-30 DOI:10.1016/j.mineng.2024.108953

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Abstract

Copper (Cu) extraction from low-grade ores is limited by the formation of secondary minerals that can passivate the surfaces of Cu-sulphide minerals in these ores. Hence, a novel approach utilizing AlCl₃ as a lixiviant was developed to modify coupled dissolution-reprecipitation processes at the mineral interface. The formation of Al-rich phases instead of Fe-hydroxysulphates enhanced Cu extraction through combined ferric-iron and proton-promoted dissolution. AlCl₃ accelerated chalcopyrite and bornite dissolution by forming soluble intermediate Cu-phases (e.g., covellite) at consistently high Eh (550–650 mV) and acidity due to the Lewis acid property of AlCl₃. X-ray diffraction analysis revealed that Na-bearing jarosite [(K_0.61Na_0.41) Fe₃(SO₄)₂(OH)] and sideronatrite [Na₂Fe(SO₄)₂(OH)(H₂O)] formation in lixiviants without AlCl₃ decreased Fe³⁺_(aq) availability for Cu-sulphide minerals dissolution. In contrast, significant amounts of AlSO₄⁺_(aq) formed in the AlCl₃-rich lixiviant at pH 1–3, which reduced the sulphate activity and decreased the saturation state of the Fe-hydroxysulphates. Further, AlCl₃ promoted the formation of amorphous, porous Al-rich phases, facilitating quick Fe diffusion through the passivating layer and improving Cu recovery compared to lixiviants containing CaCl₂, NaCl, or acid-only.

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使用富含氯化铝的酸性活化剂提高铜的迁移率

从低品位矿石中提取铜（Cu）受到次生矿物形成的限制，这些次生矿物可以钝化这些矿石中硫化铜矿物的表面。因此，我们开发了一种利用 AlCl3 作为钝化剂的新方法，以改变矿物界面的溶解-再沉淀耦合过程。富铝相的形成取代了铁-羟基硫酸盐，通过铁-铁和质子共同促进溶解，提高了铜的提取率。由于 AlCl3 的路易斯酸特性，在 Eh 值（550-650 mV）和酸度持续较高的情况下，AlCl3 通过形成可溶的中间铜相（如褐铁矿），加速了黄铜矿和辉铜矿的溶解。X 射线衍射分析表明，在不含 AlCl3 的利休剂中形成的含 Na 的绿泥石 [(K0.61Na0.41) Fe3(SO4)2(OH)] 和菱铁矿 [Na2Fe(SO4)2(OH)(H2O)] 减少了硫化铜矿物溶解所需的 Fe3+（aq）。与此相反，在 pH 值为 1-3 时，富含 AlCl3 的活化剂中形成了大量 AlSO4+(aq)，从而降低了硫酸盐活性，并降低了铁-羟基硫酸盐的饱和状态。此外，与含有 CaCl2、NaCl 或纯酸的钝化剂相比，AlCl3 促进了无定形多孔富铝相的形成，有利于铁快速通过钝化层扩散，并提高了铜的回收率。

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来源期刊

Minerals Engineering 工程技术-工程：化工

CiteScore

8.70

自引率

18.80%

发文量

519

审稿时长

81 days

期刊介绍： The purpose of the journal is to provide for the rapid publication of topical papers featuring the latest developments in the allied fields of mineral processing and extractive metallurgy. Its wide ranging coverage of research and practical (operating) topics includes physical separation methods, such as comminution, flotation concentration and dewatering, chemical methods such as bio-, hydro-, and electro-metallurgy, analytical techniques, process control, simulation and instrumentation, and mineralogical aspects of processing. Environmental issues, particularly those pertaining to sustainable development, will also be strongly covered.