Recovery of Indium from Hard Zinc Slag by Pressure Leaching and Solvent Extraction

Abstract

In this study, hydrometallurgical processes involving pressure acid leaching and solvent extraction were developed to aid recovery of indium from zinc slag, which is produced in the imperial smelting process. Four different acid leaching methods were studied, namely atmospheric leaching, atmospheric leaching with KMnO 4 , roasting-atmospheric leaching, and oxygen pressure leaching in a sulfuric acid medium. Oxygen pressure acid leaching is the most effective method for indium extraction, and 94.1% of indium was leached under the optimum conditions, i.e., 300 g/L H 2 SO 4 ,oxygen pressure 0.4 MPa, liquid/solid ratio 10 mL/g, and temperature 100°C for 5 h. X-ray diffraction and scanning electron microscopy examination of the raw material and leaching residue samples indicated that the intermetallic compounds Cu 5 Zn 8 and Cu 2 Zn, metallic zinc, and iron in the raw material dissolved, leaving the insoluble components PbSO 4 and Pb as the major compounds in the leaching residue. A 98.5% proportion of the indium in the leaching solution was selectively extracted with 30% bis(2-ethylhexyl) phosphate and 70% kerosene by three-stage counter-current extraction, and 99.5% of the indium in the loaded organic phase was stripped by 6 mol/L HCl through four-stage countercurrent stripping. The overall recovery yield of indium through all processes was approximately 92%.

A New Method and Mechanism of Oxidation/Ammonia Leaching-Phosphoric Acid Synergistic Regulation of Nickel Smelting Slag for Graded High-Value Recovery of Iron and Nickel

“…The primary requirement for the preparation of FePO 4 is the efficient leaching of the nickel smelting slag. At present, the leaching techniques of nickel smelting slag are mainly concentrated in atmospheric pressure leaching, high-pressure acid leaching, − and oxygen pressure leaching, and all of which have demonstrated effectiveness. However, they pay less attention to the simultaneous leaching of Fe and Ni.…”

The Pseudo-Protic Ionic Liquids TOAH+Cl− and TODAH+Cl− as Carriers for Facilitated Transport of In(III) from HCl Solutions

“…In this case, the theoretical and experimental extraction order is 15C5 > B15C5 > TB15C5. Various hydrometallurgical processes involving pressure acid leaching and solvent extraction are investigated for the recovery of indium from zinc slag, which is produced in the imperial smelting process [ 9 ]. Pressure leaching with sulfuric acid is the preferred method for recovering indium from the slag, and again, indium is extracted with D2EHPA and stripped in HCl medium.…”

The Pseudo-Protic Ionic Liquids TOAH⁺Cl^- and TODAH⁺Cl^- as Carriers for Facilitated Transport of In(III) from HCl Solutions

“…In this case, the theoretical and experimental extraction order are 15C5 > B15C5 > TB15C5. Various hydrometallurgical processes involving pressure acid leaching and solvent extraction are investigated for the recovery of indium from zinc slag, which is produced in the imperial smelting process [8]. Pressure leaching with sulfuric acid is the preferred method to recover indium from the slag, and again, indium is extracted with D2EHPA and stripped in HCl medium.…”