In order to determine the exploitation potentiality of a kaolin deposit from Atacama in the north of Chile, two types of kaolin (K-1 and K-2) were characterized by XRD, XRF, SEM/EDXS, size distribution, whiteness and DSC. Kaolinite, quartz, muscovite and albite were recognized as main constituents of the ore deposit, and also a significant amount of impurities that negatively impacts on quality were detected. Results show that the low quality presented by the samples, especially K-2, impedes their industrial use as raw material and further mineral concentration processes are proposed. Finally, the results of thermal analysis confirm a conversion to metakaolin that could be the basis for an alternative processing route.

Copper slag is a massive metallurgist waste. Annual production rises up to 24.6 million tons, approximately, and the main environmental impact derived from slag disposal is the usage of great soil extensions and the resulting visual contamination of the landscape. Along time, copper slag has been used in the manufacture of concrete and cement mortars. Thus, with the aim of verifying binder-type influence in the final hardness of mortars, two types of cement were used: regular cement and high initial resistance cement. Copper slag was characterized from the chemical, mineralogical and grading viewpoints. Official Chilean regulations were used in the applied methodology for the determination of some important slag parameters. Compression and flexural strength trials were carried out on cement mortars in specialized laboratories. The obtained results showed that mortars manufactured with copper slag presented a better resistance to compression and flexural strength than mortars manufactured with normal sand, and those made with high initial resistance cement were even better. It can be concluded from this work that copper slag offers optimal mechanical characteristics to be used in the manufacturing of cement mortars, becoming a sustainable and adequate alternative material for usage in the construction industry.

The use of copper slag as a partial substitute for cement in mortar preparation was studied. Copper slag samples were collected from three dumps in the Atacama Region (Northern Chile). Mortars of 40x40x160 mm (width, height, length) and curing times of 7, 28 and 90 days were used in mechanical testing. Tests were performed with 0% (control mortar), 5, 10, 15 and 20% copper slag as partial replacement of cement. The results of mechanical tests showed a gradual increase in compressive and flexural strength at 7, 28 and 90 days in mortars containing copper slag when compared with the control mortar. The major differences between the control and copper slag mortars are evident after 7 days, which indicates that the presence of slag in the blends has a retardant effect on the hardening process. On the other hand, at 90 days, compressive and flexural strength was very similar for both control mortar and mortars containing copper slag. Optimal compressive and flexural strength values are achieved with 5% of cement substitution by copper slag. The study concludes that the use of copper slag in mortars presents a viable alternative for partial cement replacement, and also contributes to mitigate adverse environmental effects of copper mining.

The significant volume of copper smelting slags poses environmental challenges, particularly concerning soil and surface water contamination. However, these slags contain valuable elements such as copper and iron, the recovery of which can contribute to both environmental protection and the circular economy in Chile. This study analyzes, at both laboratory and industrial scales, the recovery of copper sulfides from the slags of the Hernán Videla Lira Smelter in Atacama, Chile. Physical, chemical, and mineralogical characterizations were performed, along with flotation tests (rougher and cleaner) to optimize the grinding degree, pH, reagents, and flotation times. The slag, with a copper grade of 0.71%, contains fayalite, magnetite, quartz, pyrite, and chalcopyrite. In the laboratory, the concentrate obtained in the rougher stage showed a copper grade of 3.7% with a recovery rate of 62.1%; in the cleaner stage, the grade increased to 24.4%, with a recovery rate of 71.7%. At the industrial level, the rougher–cleaner circuit produced concentrates with a copper grade of 27.9% and a recovery rate of 87.5% processing 1344 tons per day, thus demonstrating the viability of this methodology.