Response Surface Methodology for Optimization of Copper Leaching from Refractory Flotation Tailings

Abstract

Response surface methodology is used to optimize the leaching process for refractory flotation copper tailings. The proportion of the refractory combination oxide copper (chrysocolla) is 64.84%. At present, few studies have examined the leaching of chrysocolla. In this study, we examine the effects of several variables, including the amount of concentrated sulfuric acid, leaching temperature, and leaching time, on leaching efficiency. Using a response surface methodology, we develop a quadratic model relanbting all the above experimental variables with leaching efficiency. The resulting model is highly consistent with experimental data. According to the model, the factor with the greatest influence on leaching efficiency is the amount of concentrated sulfuric acid. According to the model, the optimal leaching conditions are 85 kg/t concentrated sulfuric acid, a leaching temperature of 68.51 • C, and a leaching time of 4.36 h. The actual measured leaching efficiency under these conditions is 85.86%, which is close to the value of 86.79% predicted by the model. We study the leaching processes using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) surface scan analyses. Both methods allow us to explore the content of the main element and visually observe its distribution, allowing us to develop effective methods for treating low-grade oxide ores.

A Holistic Approach in Re-Mining Old Tailings Deposits for the Supply of Critical-Metals: A Portuguese Case Study

“…A re-mining project through reprocessing techniques is feasible, and studies have worked with hydrometallurgical methods to recover metals from residues could ensure: studies of recovering copper from refractory flotation tailings reached over 86% efficiency [17]; reprocessing of cassiterite tailings by froth flotation with the addition of alternative reagents [26], proving that conventional flotation has better results. Around 70% of the cassiterite was recovered on the froth.…”

“…It is known that factorial designs are efficiently used to study the response of experimental conditions in many experiments [17]. When an experimental design is not possible, the data obtained from experimental research could also be treated by regression methods.…”

“…The F-values of tests are parameters for comparing variance with error variance, and they are the ratios of mean squares. Moreover, p-values are the probabilities of F-value statistics to be exceeded [17]. The lack-of-fit (LOF) test was used to evaluate the adequacy of the models when it was possible.…”

“…Through the prediction and verification of optimization conditions, a three-dimensional surface map is used intuitively. A contour plot, which is the projection of the response surface map, was used for better visualization of the optimal condition of a series of experiments [17][18][19][20].…”

A Holistic Approach in Re-Mining Old Tailings Deposits for The Supply of Critical Metals: A Portuguese Case

“…It is known that factorial designs are efficiently used to study the response of experimental conditions in many experiments, as well described by [10]. When it is not possible to do an experimental design, the data obtained from experimental research could also be treated by regression methods.…”