Compositions and methods for the separation of metals

Inactive Publication Date: 2014-05-29
GEORGIA TECH RES CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, conventional platinum recovery is complicated by its reliance on aqua regia and possible subsequent precipitation of the dissolved platinum from the solution.
Aqua regia dissolves all the metals at the same time and cannot separate them out, resulting in low-purity platinum which cannot go back to the product stream directly; it has to be refined, but refining is costly.
Moreover, aqua regia is relatively dangerous to work with,

Method used

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  • Compositions and methods for the separation of metals
  • Compositions and methods for the separation of metals
  • Compositions and methods for the separation of metals

Examples

Experimental program
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Effect test

example 1

[0051]Layers of 250-nm-thick Au, Pd, Ag, and Pt, was deposited, onto a 9-cm2 silicon substrate each, with 20-nm-thick chromium as the adhesion layer (chromium was not soluble in any reaction medium) to avoid the error that might be introduced due to peel-off of the noble metal metallization layer. The metalized substrates were immersed in 20 mL of 3:1 v / v SOCl2-py at room temperature with mild shaking for a preset duration, taken out, rinsed thoroughly, dried, and weighed. No weight loss was detected of a platinum film after it was immersed in the SOCl2-py mixture at room temperature or even at 70° C. (refluxing) for 1 week.

[0052]FIG. 1 shows the kinetic results of the dissolution of noble metals in the mixture of SOCl2 and pyridine (py) with a volumetric ratio of 3:1. SOCl2 dissolved Au at a rate of 0.3 mol m−2 h−1 at room temperature, which is faster than Au dissolution in conventional cyanide leaching agents (−2 h−1) and iodide solutions (−2 h−1). Silver (Ag) and Pd also dissolve...

example 2

[0053]Different solutions in the method were analyzed by different techniques. X-ray photoelectron spectroscopy of the reaction of gold in SOCl2-py showed the Au 4f7 / 2 binding energy at 86.6 eV characteristic of the oxidation state of Au(III). To demonstrate that Au was oxidized to Au(III) instantaneously, SOCl2-pyridine vapor was used to etch an Au / Si surface. Au(III) was confirmed on the vapor-etched Au / Si surface by XPS and Raman spectroscopy in the form of AuCl4−. Vibration modes of Au(III)-Cl, however, were not observed in the Raman spectrum probably because they were covered by the strong fluorescence background. Actually, after the 0.03 mol L−1 Au / 3:1 SOCl2-py solution was stored at room temperature in a dark room for 150 days, a large amount of yellow precipitate was observed and the solution turned into a dark suspension. [AuCl4]− was confirmed in the Raman spectrum of the precipitate. Therefore, [AuCl4]− appeared to form as a result of Au dissolution in SOCl2-py mixtures. ...

example 3

[0057]Gold nanoparticles were synthesized by reducing 12 mg HAuCl4.3H2O in 10 mL oleylamine at 105° C. for 2 h under an Ar blanket, collected by precipitation with ethanol and centrifugation, and washed with mixtures of acetone and hexane. Platinum nanoparticles were synthesized by reducing 30 mg H2PtCl6.6H2O in 20 mL ethylene glycol (containing 35 mg polyvinylpyrrolidone, Mw=29000) at 165° C. for 2 h under an Ar blanket, collected by precipitation with acetone and centrifugation, and washed with mixtures of acetone and ethanol [17].

[0058]20 mg dried gold nanoparticles and 5 mg dried platinum nanoparticles were mixed, and then added into 10 mL SOCl2 to form a dark brown mixture. A certain amount of pyridine was added at room temperature, changing the colour of the mixture to light brown. The solution was diluted into 200 mL acetonitrile. The dissolved Au went into the solution; the non-dissolved nanoparticles were precipitated out of the solution, washed, and collected. The yield wa...

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Abstract

Methods and compositions are described for preparing metal salts and selectively separating metals from substrates and other metals. The methods can include a thionyl reagent that reacts with a metal in a solution to produce a metal salt. The reaction can be controlled by varying reagents and conditions such that the method can be used to selectively separate one or more metals from another metal or from a substrate. The method can also be used for removing metals from a surface. Compositions produced by the method are also described.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61 / 379,857 filed 3 Sep. 2010, the entire contents and substance of which are hereby incorporated by reference in its entirety as if fully set forth below.TECHNICAL FIELD[0002]The various embodiments of the present invention relate generally to the reaction of thionyl reagents with metals, the use of that reaction to selectively separate metals from mixtures and more particularly to compositions and methods for achieving the separation.BACKGROUND[0003]Dissolution of noble metals is important for metallurgy, catalysis, organometallic chemistry, syntheses and applications of noble metal nanoparticles, and recycling of noble metals. Aqua regia (“royal water”) has been used for centuries as a powerful etchant to dissolve noble metals. Aqua regia is a simple 1:3 mixture of concentrated nitric and hydrochloric acids can dissolve noble metals such as gold, palladium, an...

Claims

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Application Information

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IPC IPC(8): C22B7/00
CPCC22B11/046C23F1/10C23F1/12C23F1/44Y02P10/20C22B3/26C22B7/006
Inventor LIN, WEIWONG, CHING P.ZHANG, RONGWEI
Owner GEORGIA TECH RES CORP
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