**2. Contributions**

Seventeen articles have been published in this Special Issue of *Metals*, encompassing the fields of mineral processing and extractive metallurgy [5–21]. These articles cover a wide range of topics in the field and provide some ideas for active researchers who are working on the production of valuable metals from primary and secondary resources. Similarly, researchers from different disciplines can contribute to the enrichment of this Special Issue, through sharing multidisciplinary views on the outputs of each article.
