The generation of mining waste commonly led to the use of spaces for its disposal. Challenges like mitigating the damage to surrounding communities have promoted the need to reuse, recycle and/or reduce their generation. Besides, these residues may become a source of materials, which are capable of being recovered and reused in several industries, minimizing the environmental impact. In the mining region of Pachuca, Mexico, waste from the mining industry have been generated for more than 100 years, which have a high SiO2 content that can be recovered for various industrial applications. This work aims to recover silica from a material of the Dos Carlos dam. A columnar system composed of two-stage of cleaning was used, considering a JLT (surface liquid rate) value of 0.45 and 0.68 cm/s, respectively; while the Jg (surface gas rate) value was 0.30 cm/s for both stages. Similar bubble sizes in the range of Jg 0.10 to 0.30 cm/s, with values between 0.14 and 0.16 cm in the first stage, and 0.05 to 0.06 cm in the second one. This provided a recovery of 75.10% for all the allotropic phases of silica (quartz, trydimite, and cristobalite) leaving a concentration of 24.90% of a feldspathic phase (orthoclase), as flotation tails.

China, Vietnam, Brazil, and Russia have the largest deposits of rare earths. However, in recent works, the occurrence of light rare earth elements has been demonstrated in an exhalative sedimentary type mineral (SEDEX) in Mexico, with adequate Ce and Nd contents. Additionally, it is this mineral that has been used to study the cation exchange capacity of non-metallic minerals and organic materials, such as bentonite, diatomite, and eggshell. To carry out this work, the crushed and ground SEDEX ore was leached using HCl, H2SO4, and HNO3. Subsequently, the liquid containing the Ce and Nd ions extracted from the mineral was put in contact with the respective ion exchangers, evaluating the effect of temperature and pH to determine the cation exchange efficiency of each exchanger tried. It was found that the best leaching results were achieved with the H2SO4, obtaining an extraction of Ce and Nd of 97.6% and 95.7%, respectively. On the other hand, in the case of cation exchange, the best results found for the extraction of Ce and Nd were using diatomite at a temperature of 323 K and a pH of 3, obtaining an extraction of 99.06% Ce and 99.07% Nd.

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