Magnetic Adsorbents for the Recovery of Precious Metals from Leach Solutions and Wastewater

Abstract

Precious metals which include the platinum group, gold, and silver, play indispensable roles in high technology industries of the modern world due to their outstanding physical and chemical properties. As a result of diminishing availability of mineral sources, increasing demand, and environmental concerns, the recovery of precious metals from both leaching and industrial waste solutions is becoming a very important technology. Magnetic solid phase extraction (MSPE) is a technique that has received substantial consideration in the separation and recovery of precious metals because of the many advantages it offers compared to conventional methods. This technique is based on the extraction of different analytes from solutions using solid adsorbents with magnetic properties. This review focuses on different types of magnetic adsorbents, the main procedures used for synthesis, characterization and their application in precious metals recovery based on recently published literatures.

Magnetic Solid Phase Extraction as a Promising Technique for Fast Separation of Metallic Nanoparticles and Their Ionic Species: A Review of Recent Advances

“…Magnetic materials can exhibit different types of magnetism, mainly ferromagnetism, superparamagnetism, diamagnetism, antiferromagnetism, and ferrimagnetism [ 22 ]. Magnetic particles composed of Fe, Co, Ni, or their metal oxides/alloys usually possess ferromagnetic or superparamagnetic properties [ 34 ]. Upon the application of an external field, magnetic particles tend to act as permanent magnets that form lattices or aggregates depending on the magnetic interaction.…”

“…Ferromagnetic particles possess permanent magnetism and result in a lattice form when the magnetic field is removed. In contrast, superparamagnetic particles are attracted to magnetic fields; however, magnetic properties do not remain after the elimination of the magnetic field [ 34 ]. Among the magnetic particles, iron oxides, such as magnetite (Fe 3 O 4 ) and maghemite ( γ -Fe 2 O 3 ), have received considerable attention and become widely used as magnetic cores in magnetic particles.…”

Valuable Metal Recycling

“…The separation and purification of gold from leach solution is also an important issue in terms of gold recovery. Aghaei et al [3] summarized the potential use of magnetic adsorbents, such as magnetite, for selective adsorption of gold ion over other metal ions, such as Fe and Ni.…”

Mineral processing: leaching process of chromium and recovery of platinum group elements from Northwestern Saudi Arabian Ophiolitic chromite

“…PGEs (Pt, Pd, Ir, Os, Rh, Ru) are often linked with gold and are of main profitable significance [16][17][18][19]. Recently, magnetic solid phase extraction has been used for the separation of PGMs from leach solutions and wastewater [20]. PGMs have very few occurrences where they are present in an ore deposit at economically extractable levels [21,22].…”