RU2516153C2 - Method of production of gold nanoparticles from raw material containing iron and non-ferrous metals - Google Patents

Abstract

FIELD: nanotechnology.

SUBSTANCE: invention relates to the technology of production of gold nanoparticles. The method of production of gold nanoparticles from the raw material containing iron and non-ferrous metals comprises preparation of the chlorazotic acid solution of gold using chlorazotic acid. Then floatation extraction of gold precursors is carried out with cationic surfactants from the solution, separation and evaporation of the organic phase to concentrate the gold precursors. Then the concentrate reduction is carried out to obtain dispersion of gold nanoparticles. At that the starting material is first treated with hydrochloric acid to form the insoluble precipitate. Production of chlorazotic acid solution is carried out by dissolving in chlorazotic acid solution of insoluble precipitate. Before floatation extraction of precursors the nitric acid is removed from chlorazotic acid solution with methyl or ethyl alcohol or hydrochloric acid.

EFFECT: improvement of efficiency of the method of production of nanoparticles, namely the increase in the number of gold nanoparticles obtained or its hybrids with noble metals.

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Description

The invention relates to a technology for producing gold nanoparticles or gold nanohybrids with other metals. Gold nanoparticles are used in the perfumery, cosmetics, chemical, jewelry industries; for the treatment and diagnosis of diseases, for the analytical determination of various substances by the method of surface-enhanced Raman spectroscopy.

A known method of producing gold nanoparticles from iron ore (patent of the Russian Federation No. 2424339). It is taken as a prototype. Iron ore is floated, the concentrate is dissolved in aqua regia, the solution is subjected to ion flotation with surfactants to concentrate the gold precursors, and then the gold precursors are reduced with tea leaf extract. The method has disadvantages. Firstly, iron ore is not processed comprehensively. From the concentrate, in addition to precious metals, nanoparticles of iron oxides and non-ferrous metals can be obtained. Secondly, royal vodka does not fully extract gold from raw materials. Thirdly, the excess nitric acid that remains after decomposition of the concentrate with aqua regia interferes with the ionic flotation of gold, because only chloride complexes of gold are well floated by cationic surfactants.

An object of the invention is to increase the number of obtained nanoparticles of gold or its hybrids with noble metals.

The technical result is achieved by the fact that in the method for producing gold nanoparticles from raw materials containing iron and non-ferrous metals, including the preparation of a royal water solution of gold using aqua regia, flotoextraction from solutions of gold precursors by cationic surfactants, separation and evaporation of the organic phase to concentrate the gold precursors and recovery of the concentrate to obtain a dispersion of gold nanoparticles according to the invention, the feed is first treated with hydrochloric acid to form an insoluble precipitate, p luchenie tsarskovodochnogo solution is carried out by dissolving in aqua regia and the insoluble precipitate before flotoekstraktsiey precursor is removed from the nitric acid solution tsarskovodochnogo methyl or ethyl alcohol or hydrochloric acid.

If the iron ore powder is treated with hydrochloric acid, then ions of iron, silicon, nickel, cobalt, manganese, copper, zinc, silicon pass into the solution. The remaining ore particles become finer and more porous. They dissolve better in aqua regia. After dissolution in aqua regia, nitric acid interferes with the formation of salts of the gold chloride complex and cationic surfactant. Nitric acid is removed with reducing agents - lower alcohols or hydrochloric acid. With this method of processing raw materials, it becomes possible to obtain nanoparticles of iron oxides and silicon oxide, nanoparticles of non-ferrous metals from aqueous solutions of hydrochloric acid by known methods. The invention is illustrated by examples.

Example 1

An iron ore powder containing 13.5% Fe ₂ O ₃ + Fe ₃ O ₄ according to X-ray diffractometry, 86.5% SiO ₂ , and weighing 300 g was treated with 580 ml of 6 M HCl. Boiled for 5 hours with stirring. The upper brown liquid layer of hydrochloric acid salts of iron and other elements was drained. Magnetite and silicon dioxide nanoparticles were prepared from it by known methods. An insoluble blue precipitate was treated by boiling in aqua regia for 5 hours. The resulting solution was treated twice by boiling with 6 M HCl to decompose nitric acid. The remainder of the wet salts was dissolved in 1 M HCl to give 10 ml of solution. 10 ml of the resulting solution and 0.03345 g of cetylpyridinium chloride (CPC) dissolved in 5 ml of ethanol were added to a flotator with 1000 ml of 0.5 M HCl to 0.0001 M in a flotator. 50 ml of organic solvent was added to the flotator and floated for 1 hour. After separation and evaporation of the organic phase, a small amount of white powder was obtained, which was dissolved in 10 ml of water. The solution in a test tube was purged with nitrogen and sonicated. A pink solution was obtained, to which 1.5 ml of a 0.6 M solution of hydrazine hydrate reducing agent was added and stirred for another 10 minutes. To the resulting mixture was added 1 ml of 2 M KOH, stirred for 10 minutes. A cloudy solution was obtained, which turned brown in a day. The brown color of the dispersion indicates that the size of the gold nanoparticles is approximately 20 nm. The UV-visible spectrum of this dispersion had a plasma absorption band with a maximum of 530 nm.

After settling the solution, a brown precipitate appeared as a result of aggregation of nanoparticles. The precipitate was separated by centrifugation, washed with ethanol and dried. Received 0.45 g of powder. Gold nanopowder was used to take photographs using a transmission electron microscope. The size of the nanoparticles according to TEM was 15 ± 6 nm.

Example 2

Scrap gold-plated transistor legs were dissolved in aqua regia. To remove nitrogen oxides, the resulting solution was treated with methyl alcohol and evaporated to wet salts, which were then dissolved in 1 M HCl. The resulting 50 ml solution was combined with 1000 ml of 0.5 M HCl and loaded onto a flotator. 1.34 g of CPC dissolved in 10 ml of ethyl alcohol was added thereto. The solution immediately became cloudy. From above, 50 ml of a mixture of chloroform, toluene and amyl alcohol in a ratio of 1: 3: 6 (by volume) was added to the flotator and floated for 1 hour. The upper layer of the gold precursor with solvents was separated. The solvents evaporated. Received the remains of the precursor in the form of a paste of dark brown color. The paste in an amount of 0.26 g was dissolved in 20 ml of distilled water with stirring with ultrasound for 10 minutes. A clear solution was obtained which became dark after adding 3 ml of a 0.6 M hydrazine hydrate solution. 2 ml of a 2 M KOH solution was added to the tube and mixed for another 10 minutes. A dark brown dispersion of gold nanoparticles was obtained. The dispersions thus obtained were diluted 2 times with ethyl alcohol several times and centrifuged. The precipitates were washed with alcohol and centrifuged again. After evaporation of the alcohol, the gold nanopowder was examined on a TEM. Gold nanoparticles had a size of 5 ± 3 nm.

Example 3

Iron ore powder weighing 300 g of the composition, as in example 1, was decomposed with aqua regia in a known manner. Received 0.23 g of a nanopowder with gold instead of 0.45 g according to the new method.

Thus, having previously removed iron and silicon from ore and nitric acid from aqua regia, more gold nanoparticles are obtained.

Claims (1)

The method of producing gold nanoparticles from raw materials containing iron and non-ferrous metals, including obtaining a royal gold solution using aqua regia, flotoextraction from a solution of gold precursors by cationic surfactants, separation and evaporation of the organic phase to concentrate the gold recurs and recovering the concentrate to obtain a dispersion of gold nanoparticles, different the fact that the raw material is first treated with hydrochloric acid with the formation of an insoluble precipitate, getting tsarvodovodnoy solution astvoreniem in aqua regia and the insoluble precipitate before flotoekstraktsiey precursor is removed from the nitric acid solution tsarskovodochnogo methyl or ethyl alcohol or hydrochloric acid.