Modeling the Effects of NO3−, H+ and Potential HNE on Nitro TAP through Response Surface Methodology

Abstract

Nitration is a chemical process that introduces a nitro group into a molecule, which modifies properties of organic compounds, impacting their reactivity and physical attributes. In copper mining, elevated nitrate levels present operational difficulties, impacting recovery percentages and leading to the deterioration of organic extractants. Historically, various elements such as intense electrolyte acidity, sunlight exposure, Mn presence, high temperatures, and microbial activity have been linked to this degradation. Over time, numerous methods, including the introduction of additives and the implementation of recirculation approaches, have been developed to address the nitration issue. Mathematical modeling of nitration (like response surface methodology, RSM) based on explanatory variables, such as NO3−, H+, and Potential HNE, has the potential to obtain a better understanding of nitration processes. This study highlights the effectiveness of the TAP Test in assessing the aggressiveness level of nitrates in aqueous solutions and, given the increase in complexity of the minerals in mining sites, it is plausible to anticipate a rise in usage of these tests within hydrometallurgical plants in near future. Using RSM and design of experiments proved robust in examining the nitration phenomenon. Maximum TAP nitration occurred at elevated levels of NO3−, H+, and Potential HNE, with an experimental peak of 17.9%; this contrasts with the theoretical 16.25% from the fitted model (R2≅90%).