The objectives of this research are: (1) to study the process of formation of efflorescence salt crusts (ESC) on the surface of tailings dams, (2) to evaluate the possibility of recovering critical metals and raw materials, and (3) to study its effectiveness as a tailings (MT) decontaminant. To achieve these objectives, the evaporation process of 3 columns containing a mixture of MT and distilled water was monitored under laboratory conditions.

Two MT of the flotation process from the extraction of Pb-Zn were used, one from the Mazarrón mining district (MDM) and the other from the Cartagena-La Unión mining district (CLUDM). MT and ESC were analysed by particle size analysis, mineralogical and chemical composition, thermal analysis, pH, electrical conductivity, potential redox, gravimetric water content and suction. It is important to note that some critical metals according to the EU 2020 CRWs, list are present in the MT sample.

A significant growth in Zn ESC concentration was observed during the experiment. The concentration in MDM ESC is 8% higher than in the MT and in the CLUDM ESC it is 10% higher than in the MT. These results, together with the fact that ESC is water soluble, indicate the great potential of ESC treatment for metal recovery and MT decontamination.

本研究的目的是：（1）研究尾矿坝表面风化盐壳（ESC）的形成过程，（2）评估回收关键金属和原材料的可能性，以及（3）研究其作为尾矿 (MT) 去污剂的有效性。为了实现这些目标，在实验室条件下监测了含有 MT 和蒸馏水混合物的 3 个色谱柱的蒸发过程。

使用了两台 MT 的铅锌浮选工艺，一台来自 Mazarrón 矿区 (MDM)，另一台来自 Cartagena-La Unión 矿区 (CLUDM)。MT和ESC通过粒度分析、矿物学和化学成分、热分析、pH、电导率、电位氧化还原、重量含水量和吸力进行分析。需要注意的是，根据欧盟 2020 年 CRW 清单列出的一些关键金属存在于 MT 样本中。

在实验过程中观察到 Zn ESC 浓度显着增加。MDM ESC 中的浓度比 MT 高 8%，而 CLUDM ESC 中的浓度比 MT 高 10%。这些结果，连同 ESC 是水溶性的事实，表明 ESC 处理在金属回收和 MT 去污方面的巨大潜力。