24. Recovery of Critical Metals from Mine Tailings

The availability of primary resources correlated with waste production from exploration and mining activities will remain a need to satisfy the growing global demand for raw materials. The present research started with the idea that tailings and wastes from mining can be considered mineral reserves. The project aimed to increase the efficiency of resources through the recycling of residues and their integration into a circular economy concept. Special emphasis is placed on processing mine tailings to turn them into a valuable source of secondary raw materials. This is an important step toward sustainability and reducing the negative impact on the environment. This chapter presents the objectives targeted by the REVIVING research project. Therefore, the aim was to obtain improved models for efficiently recycling metals from residues in selected case study mines, based, for the first time, on the manipulation of the microbiome existing within autochthonous tailings, using molecular data to promote the bioleaching bacterial populations, and innovative hydrometallurgy, using negative pressure. The study aimed to cover the entire cycle of obtaining metals, from secondary sources to the production of a marketable product. It also aimed to enable the efficient recycling of tailings and reduce the residues generated by the mining process, thus contributing to the reconnection of raw materials to society. The ultimate goal of the project was to find alternative sources of critical metals, as these are vulnerable to disruption of supply because their core source is restricted to just one or two regions of the world, and they are difficult to substitute within the specific technologies that use them, being vital raw materials in various new and green emerging industrial processes.