Copper Recovery and Reduction of Environmental Loading from Mine Tailings by High-Pressure Leaching and SX-EW Process

Abstract

The flotation tailings obtained from Bor Copper Mine contain pyrite (FeS2) and chalcopyrite (CuFeS2), these sulfide minerals are known to promote acid mine drainage (AMD) which poses a serious threat to the environment and human health. This study focuses on the treatment of mine tailings to convert the AMD supporting minerals to more stable forms, while simultaneously valorizing the mine tailings. A combination of hydrometallurgical processes of high-pressure oxidative leaching (HPOL), solvent extraction (SX), and electrowinning (EW) were utilized to recover copper from mine tailings which contain about 0.3% Cu content. The HPOL process yielded a high copper leaching rate of 94.4% when water was used as a leaching medium. The copper leaching kinetics were promoted by the generation of sulfuric acid due to pyrite oxidation. It was also confirmed that a low iron concentration (1.4 g/L) and a high copper concentration (44.8 g/L) obtained in the stripped solution resulted in an improved copper electrodeposition current efficiency during copper electrowinning. Moreover, pyrite, which is primarily in the mine tailings, was converted into hematite after HPOL. A stability evaluation of the solid residue confirmed almost no elution of metal ions, confirming the reduced environmental loading of mine tailings through re-processing.

Waste-to-Energy Bottom Ash Management Copper Recovery by Electrowinning

“…Thereafter, it was possible to recover 25.7% Pb and 59.8% Cu by EW operating at 10 A. Finally, it is also worth mentioning that other authors used EW for copper recovery from other kinds of solutions, such as acid mine drainage or electronic waste [23][24][25].…”

“…700 mg/L). As summarized in Table 6, several authors have studied copper extraction and recovery by EW [23][24][25], electrodeposition [32,33], ED-based technologies [34][35][36] and extraction techniques [37][38][39].…”

“…In the second case, EW was carried out after hydrometallurgical processes. In another study, EW was used after a high-pressure oxidative leaching and solvent extraction for copper recovery from AMD [25]. In that work, a solution with a high concentration of copper was introduced into the EW system (25-45 g/L), achieving a current efficiency of 95%.…”

The Use of Acid Leaching to Recover Metals from Tailings: A Review

“…In 2021, Godirilwe [50] conducted leaching experiments on tailings material from Bor Copper Mine, Serbia, considering both raw tailings and a concentrated tailings variant. Characterization of the samples revealed differences in copper and iron content, with the raw tailings containing 0.24% Cu and 3.51% Fe, while the concentrated tailings had higher levels at 0.65% Cu and 35.20% Fe, with a D50 particle size of 27 µm.…”

“…The uncertainty surrounding the behavior of tailings deposits has spurred the implementation of metallurgical procedures. Indeed, researchers have proposed diverse methodologies for recovering valuable minerals from these tailings, including bioremediation [23], bioleaching [4,24], phytostabilization [6,25], flotation [5,26], geopolymers [27], agitated acid leaching [22,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]-both in columns [47,48] and in autoclave [49,50]-and even utilizing this waste as a raw material for cement production in the construction industry [51][52][53].…”