Synthesis of Metastable Au-Fe Alloy Using Ordered Nanoporous Silica as a Hard Template

Kumar, Paskalis Sahaya Murphin; Thiripuranthagan, Sivakumar; Fujita, Takeshi; Jayavel, R.; Abe, Hideki

doi:10.3390/met8010017

Cited by 5 publications

(4 citation statements)

References 16 publications

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“…Atomic Au and Fe can form Au-Fe alloys at high temperature [23]. The unique electrical [24], magnetic [25], thermodynamic [26] and catalytic [27] properties of Au-Fe alloys have attracted great interest. It suggests that gold remains in cyanide tailings can be captured and enriched in metallic iron if a high-temperature reduction process is conducted.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Feng

et al. 2018

Metals

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Cyanide tailings are the hazardous waste discharged after gold cyanidation leaching. The recovery of gold and iron from cyanide tailings was investigated with a combined direct reduction roasting and leaching process. The effects of reduction temperature, coal dosage and CaO dosage on gold enrichment into Au-Fe alloy (FexAu1−x) were studied in direct reduction roasting. Gold containing iron powders, i.e., Au-Fe alloy, had the gold grade of 8.23 g/t with a recovery of 97.46%. After separating gold and iron in iron powders with sulfuric acid leaching, ferrous sulfate in the leachate was crystallized to prepare FeSO4·7H2O with a yield of 222.42% to cyanide tailings. Gold enriched in acid-leaching residue with gold grade of 216.58 g/t was extracted into pregnant solution. The total gold recovery of the whole process reached as high as 94.23%. The tailings generated in the magnetic separation of roasted products, with a yield of 51.33% to cyanide tailings, had no toxic cyanide any more. The gold enrichment behaviors indicated that higher reduction temperature and larger dosage of coal and CaO could promote the allocation of more gold in iron phase rather than in slag phase. The mechanism for enriching gold from cyanide tailings into iron phase was proposed. This work provided a novel route to simultaneously recover gold and iron from cyanide tailings.

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Section: Introductionmentioning

confidence: 99%

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Feng

et al. 2018

Metals

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“…It is known that the lattice parameter of fcc (Au) decreases as Fe atoms are incorporated in the Au matrix. This leads to a shift in the peak positions towards higher diffraction angles with respect to the pure Au [42]. Similarly, the lattice parameter of the bcc α(Fe) solid solution undergoes an enhancement, with respect to pure Fe, so that Fe the lattice can accommodate Au atoms, which results in peaks shifted towards smaller diffraction angles.…”

Section: As-quenched Ribbon Characterizationmentioning

confidence: 95%

Cost-Effective Nanoporous Gold Obtained by Dealloying Metastable Precursor, Au33Fe67, Reveals Excellent Methanol Electro-Oxidation Performance

et al. 2022

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In this study, we report nanoporous gold (NPG) as an economic, efficient, and stable alternative electrocatalyst for methanol electro-oxidation. The said sample was successfully prepared from an Fe-rich metastable Au33Fe67 supersaturated solid solution acting as the precursor, which was formed into ribbons by the phenomenon of rapid solidification using melt-spinning technique. The as‑quenched ribbon was then chemically dealloyed in 1 M HCl at 70 °C for different durations of time. A homogeneous, free-standing, and mechanically stable NPG sample was obtained with tunable ligament shape and size. The morphology and composition were characterized by using SEM with EDS, while the structure by XRD. The sample was examined as an electrocatalyst for methanol electro-oxidation profiting off its large surface area; cyclic voltammetry (CV) was the technique employed for electrochemical studies. In a basic solution of methanol and KOH, the sample displays a low peak potential of 0.47 V vs. Ag/AgCl for methanol electro-oxidation with a high peak current density of 0.43 mA/cm2. In addition, it demonstrates outstanding stability and high poisoning tolerance. It is noteworthy that the fabrication process of the NPG sample from start to end was intentionally opted to be sustainable, cost-effective, rapid, and feasible. The usage of critical raw materials was avoided. As a whole, the properties and results put forth by the NPG sample make it an inexpensive, sustainable, and excellent alternative as an electrocatalyst for methanol electro-oxidation.

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“…[ 9 ] Common templates include anodic aluminum oxide (AAO), silica, colloidal crystals (Figure 1), copolymer particles, and more. [ 10–14 ] For example, Wu et al. used Alternating Current‐Direct Current (AC‐DC) electrodeposition to deposit Au into the AAO template.…”

Section: Preparation Characterization and Performance Of Npgmentioning

confidence: 99%

Nanoporous gold: A review and potentials in biotechnological and biomedical applications

Xiao

Wang

et al. 2021

Nano Select

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Nanoporous gold (NPG) is one of the representatives of emerging materials that combine the advantages of nano, porous, and metallic materials. In addition to the general characteristics of nanoporous materials, NPG also has many unique properties, such as excellent structural stability, adjustable pore size, high conductivity, remarkable biocompatibility, clean surface, easy recycle and reuse, and unique electrochemical catalytic activities. These performances endow NPG promising application potentials in the fields of catalysis, environmental monitoring, energy storage, biomedicine, etc. Herein, this review summarizes the recent advances of NPG over the past decade. Besides preparation and modification of NPG, special emphasis is placed on its applications in biotechnology and biomedicine: catalysis, biosensors, biofuel cells, and drug delivery. The significant and representative studies in each area are comprehensively reviewed and analyzed as a reference for researchers working in related areas. The main challenges and future opportunities of NPG in these areas are also discussed.

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Synthesis of Metastable Au-Fe Alloy Using Ordered Nanoporous Silica as a Hard Template

Cited by 5 publications

References 16 publications

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Cost-Effective Nanoporous Gold Obtained by Dealloying Metastable Precursor, Au33Fe67, Reveals Excellent Methanol Electro-Oxidation Performance

Nanoporous gold: A review and potentials in biotechnological and biomedical applications

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