RU2380435C2 - Extraction method of precious and rare metals from solutions with low concentration at presence of ions of other metals and device for its implementation - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: inventions relate to gold extraction from solutions with low concentration at presence of ions of other metals, for instance cleaning solutions of gold-extracting plants, brines of potassium manufacturing, geothermal water, water of brine lakes and salt water. Essence consists in that through powder of metal-restorative it is passed gold-containing solution with low concentration at presence of ions of other metals during 2-240 hours. In the capacity of metal-restorative it is used lead-plated zinc powder of grade +0.001 mm - 2 mm with lead content 1-90 wt %. or powders of metals, used at temperature of solution not less than 50C and selected from the group: Zn, Fe, Ni, Pb, Sn, Sb, of grade +0.1 mm - 5 mm. Additionally before cementation powders are placed in cartridge. Received after cementation gold-containing concentrate is separated by means of intensive mechanical agitation, it is treated by nitric or acetic acid. Gold sediment is separated by filtration, dried and molten with fluxing additives with receiving of crude metal. ^ EFFECT: increase of effectiveness and selectivity of gold extraction from solutions with low concentration. ^ 3 cl, 1 dwg, 3 ex

Description

The invention relates to hydrometallurgy of precious and rare metals, in particular to processes for the extraction of gold from solutions with a low concentration in the presence of ions of other metals, for example, clarified solutions of gold recovery plants, potassium brines, geothermal waters, salt lake waters and sea water.

No cost-effective technology for recovering gold from low concentration solutions is currently unknown. The gold content in seawater varies from 0.004 mg / t to 65 mg / t. An increased gold content has been found in continental highly mineralized hot springs. Thus, the gold content in the hot spring of Arkansas (USA) amounted to 260 mg / t, ... the gold content in the water of the Great Salt Lake on Utaka is 360 mg / t, and in the water from Mono Lake in California - up to 540 mg / t (Ladeyshchikov VV Technique and technology for the extraction of gold from ores abroad. M: Nedra, 1974, pp. 266-267).

A known method of gold extraction, used in most gold-mining enterprises using the cyanide process (Metallurgy of precious metals. M: Metallurgy, 1987, p. 174). The method consists in the fact that the clarified gold-containing solution is subjected to deaeration, mixed with zinc dust and lead acetic acid and filtered to isolate a gold-zinc precipitate while gold is precipitated. Due to the large surface of leaded zinc dust, the cementation process proceeds with high speed and completeness, while the bulk of the gold is deposited during the percolation of the solution through the cake layer located on the filter surface. The disadvantage of this method is the low filtration rate of gold-containing solutions through a dense layer of zinc dust, which significantly reduces the efficiency of the process when extracting gold from solutions with a low concentration.

A known installation with vacuum frames for extracting gold from clarified cyanide solutions (Metallurgy of noble metals. M: Metallurgy, 1987, p.176). Under the vacuum created by the vacuum pump, the gold-depleted solution seeps into the frames, and the gold sludge remains on the surface of the filter cloth in the form of cake. The main amount of gold is deposited during the period when the solution leaks through a layer of zinc dust located on the surface of the filter frames. The disadvantages of the device are the low filtration rate of the solution, which does not allow cost-effective extraction of precious metals from solutions with low concentration, as well as the large areas occupied by plants for the deposition of gold by zinc dust.

A device is known for extracting gold from sea water, including a filter column filled with an adsorbent and connected to an intake Kingston (Yu.A. Ulitsky. Ocean of Hopes. M .: Education, 1983, p.24). A disadvantage of the known device is the high cost of the obtained metal.

The closest (prototype) is the method and device for extracting gold from clarified cyanide solutions using lead zinc shavings (I.N. Plaksin, Yu.D.M. Yukhtanov. Hydrometallurgy. M .: Metallurgizdat, 1949, p. 273- 276, 369-376). Currently, the deposition of gold by zinc shavings is used in small enterprises and long-built enterprises. The disadvantages of the method and device are: high zinc consumption, incomplete extraction of gold due to the fact that part of it is returned to the extractor with 25-30% coarse zinc, large sizes of the extractors, which occupy large areas, the difficulty in preparing zinc chips, low concentration of zinc chips relative to units of solution, which significantly reduces the extraction of gold from the solution.

The objective of the invention is to increase the efficiency and selectivity of the extraction of gold from solutions with low concentration, the rate of filtration of gold-containing solutions.

The technical result of the invention is achieved by the fact that in the method of extracting gold from gold-containing solutions with a low concentration in the presence of ions of other metals by cementing it in a reduced form on leaded zinc powder, the gold-containing solution is passed through leaded zinc powder of class +0.001 mm - 2 mm with a lead content of 1 -90 wt.% For 2-240 hours, after which the gold-lead concentrate is separated from zinc powder and treated with nitric or acetic acid, the precipitate is filtered, dried and plated ny with the fluxing additives known methods to obtain a crude metal.

The drawing shows a device for the extraction of precious and rare metals from solutions with a low concentration in the presence of ions of other metals, including a filter column 3 for accumulating a gold-containing solution with a hole for supplying solution 1, the handle of the filter column 5, base 2, made in the form of a rigid metal grate with a cell of the order of 10 mm, sufficient to maintain the pressure created by the solution in the filter column, a gasket 4 located inside the filter column 3 of the cartridge 9, on filled with leaded zinc powder 8 held by a metal woven mesh 7 with a cell size, ensuring the retention of the leaded zinc powder 8 in the cassette 9 and transmission of a gold-containing solution, and a metal woven mesh 6 with a mesh of at least 0.4 mm for strength.

The method is implemented by the following device. Leaded zinc powder of class 8 +0.001 mm - 2 mm with a lead content of 1-90 wt.% Is loaded into cassette 9 and installed on base 2, then a filter column 3 is installed on top, the function of which is to create pressure due to the weight of the gold-containing solution to increase filtration rate through a layer of metal-cementer. The gold-containing solution by gravity or by force, for example, by means of a pump, enters the filter column 3 through the hole 1, located mainly in the upper part of the filter column, then the gold-containing solution passes through a cassette 9 with leaded zinc powder 8, the layer of which is at least 5 mm, and leaves the filter column 3 through the drain (shown in the drawing by arrows pointing down) into the drain. After saturation of the cartridge 9 with a gold-containing concentrate for 2-240 hours, depending on the concentration of gold in the solution, this cartridge is removed from the filter column 3 and replaced with a new cartridge. Lead zinc powder 8 is discharged from cassette 9, the gold-lead concentrate is separated from the zinc powder by intensive mechanical mixing by known methods, the zinc powder is reused, and the gold-lead concentrate is treated with nitric or acetic acid by known methods, the precipitate is filtered, dried and melted with fluxing agents additives to obtain crude metal by known methods.

In relation to geothermal waters, where the water temperature reaches more than 50 ° C, cement-metals selected from Zn, Fe, Ni, Pb, Sn, Sb with particle sizes of 0.1 mm - 5 mm can also be used instead of leaded zinc powder. The specific choice of these cementing metals depends on the chemical composition of geothermal water and the amount of metal impurities in geothermal waters, primarily As, Cu, Pb, Se, Fe, Ni. Since high water temperatures accelerate the process of deposition of precious metals by tens of times, therefore, powders of these cementing metals of larger sizes can be used.

A preferred embodiment of the apparatus of the invention has been described above, although the invention is not limited thereto. Obviously, various changes and modifications are possible according to the essence of the invention within its scope defined by the claims.

The method and device are illustrated by the following non-limiting examples.

Example 1. In a cassette with a capacity of 3 cubic meters. cm load leaded zinc powder of class +0.001 mm - 2 mm. The cartridge is installed in the filtering device and fixed. The filter device is connected to the aquarium pump. The complete assembly is lowered into a bath with 100 l of artificial brine 300 g / l of sea salt with an Au content of 0.1 mg / l. Within 24 hours, the pump passes the specified brine through a filtering device. After 24 hours, the residual gold content in the brine is determined and the capacity of the zinc powder is calculated. At the initial Au content of 0.1 mg / L, after 24 hours, the residual gold content was 0.03 mg / L. The capacity of lead zinc powder was 1.2 g Au per 1 kg of zinc powder.

Example 2. In a cassette with a capacity of 3 cubic meters. cm load leaded zinc powder of class +0.001 mm - 2 mm. The cartridge is installed in the filtering device and fixed. The filter device is connected to the aquarium pump. The complete device is immersed in a bath with 200 l of an artificial solution of sea water with an Au content of 0.025 mg / l. Within 24 hours, the pump passes the specified solution through a filtering device. After 24 hours, the residual gold content in sea water is determined and the capacity of the zinc powder is calculated. At the initial Au content of 0.025 mg / L, after 24 hours, the residual gold content was 0.01 mg / L. The capacity of lead zinc powder was 1.5 g Au per 1 kg of zinc powder.

Example 3. In a cassette with a capacity of 6 cubic meters. cm load leaded zinc powder of class +0.001 mm - 2 mm. The cartridge is installed in the filtering device and fixed. The filter device is connected to the aquarium pump. The complete assembly is immersed in a bath with 200 l of artificial solution of geothermal water at a temperature of 50-60 ° C with an Au content of 0.2 mg / l. Within 24 hours, the pump passes the specified solution through a filtering device. After 24 hours, the residual gold content in the artificial solution of geothermal water is determined and the capacity of the zinc powder is calculated. At the initial Au content of 0.2 mg / L, after 24 hours, the residual gold content was 0.05 mg / L. The capacity of lead zinc powder was 2.48 g Au per 1 kg of zinc powder.

Example 4. In a cassette with a capacity of 6 cubic meters. cm load powder of antimony metal (Sb) class +0.1 mm - 5 mm The cartridge is installed in the filtering device and fixed. The filter device is connected to the aquarium pump. The complete assembly is immersed in a bath with 200 l of artificial solution of geothermal water at a temperature of 50-60 ° C with an Au content of 0.2 mg / l. After 24 hours, the residual gold content in this water is determined and the capacity of the metal antimony powder is calculated. At the initial Au content of 0.2 mg / L, after 24 hours, the residual gold content was 0.06 mg / L. The capacity of the metal antimony powder was 2.31 g Au per 1 kg of metal antimony.

The proposed method can be used to extract gold from clarified solutions of tailings of gold recovery plants, potassium production brines, geothermal waters, waters of salt lakes and sea water. The proposed method and device for the extraction of gold from solutions with a concentration of less than 0.1 mg / l allows to achieve a high degree of gold recovery - more than 90% in reduced form from solutions in the presence of salts of other metals and at the same time significantly increase the rate of filtration of gold-containing solutions.

Claims (3)

1. The method of extracting gold from solutions with a low concentration in the presence of ions of other metals, including the cementation of gold in a reduced form on a metal powder of a reducing agent with the release of a gold-containing precipitate, characterized in that as a metal-cement powder use lead zinc powder of class +0.001 mm - 2 mm with a lead content of 1-90 wt.% Or metal powders used at a solution temperature of at least 50 ° C and selected from the group: Zn, Fe, Ni, Pb, Sn, Sb, class +0.1 mm - 5 mm, with powders before cementation placed in a cassette, cementation is carried out by passing a gold-containing solution through a cassette for 2-240 hours, the gold-containing precipitate is separated by intensive mechanical stirring, it is treated with nitric or acetic acid, separated by filtration, dried and melted with fluxing agents to obtain crude gold. 2. The method according to claim 1, characterized in that when using leaded zinc powder as a metal reducing agent after separation of a gold-bearing precipitate containing lead, zinc powder is reused. 3. A device for extracting gold from solutions with a low concentration in the presence of ions of other metals by carburizing, including a filter column with a hole for supplying a solution and powder of a reducing metal, characterized in that it is equipped with a base for mounting a filter column on it, made in the form of a rigid a metal grid with a cell of the order of 10 mm, sufficient to maintain the pressure created by the solution in the filter column, and a gasket, the filter column is made with handles and it is three replaceable cartridge filled with a reducing metal powder held-woven metal mesh with a mesh size providing retention reductant metal powder in the cassette and passing the gold-containing solution and the metal woven mesh with a mesh size of at least 0.4 mm, for strength.

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