Extraction method of gold from electrolyte for electropolishing of products

FIELD: metallurgy.

SUBSTANCE: invention relates to extraction method of gold from ferrostan electrolyte for electropolishing of products, containing complex compound gold ion with thiourea. Method includes destruction of complex by means of treatment of electrolyte 33.0-67.5% solution of hydrogen peroxide. Treatment is implemented at concentration of sulfuric acid, equal to 0.19-0.45 mole/l, with restoration of gold up to the metal.

EFFECT: increasing of gold extraction ratio of high grade and process simplification.

1 tbl, 2 ex

 

The technical field

The invention relates to chemical technology of obtaining gold.

The level of technology

There are various ways to extract gold from various materials with the transfer of gold in solution, for example, using organic complexing reagents (Chernyak A.S., Bobrov A.S., Skobeyev I.K. Analysis and technology of precious metals. M.: metallurgy, 1971, s).

An effective method of extracting gold from its containing waste, such as coatings, products, is the method of extraction of the particles of gold from hydrochloric timesaving solutions of different extractants. Among the last - middle and acidic esters alkylphosphonic acids and their salts, dialkyldithiophosphoric acids and their esters and other solvents (Chernyak A.S., Bobrov A.S., Skobeyev I.K. Analysis and technology of precious metals. M.: metallurgy, 1971, s. Nikitin, M.K., Saprykina LN. "1X all-Union conference on the chemistry, analysis and technology of the precious metals" - abstracts, Krasnoyarsk. 1973, p.40).

The disadvantages of the known methods are:

incomplete extraction of metal 90-98% with the optimal ratio of aqueous and organic phases (1-5):1;

the degree of extraction of gold depends strongly on the nature of the inorganic anion and a decrease in the number of ClO4>J>SCN>Br>Cl (Shvedova N., A. I. busev, N. Klimenko, Koroleva 21 all-Union conference on hydrometallurgy" proc. Dokl. M.: Nauka, 1974, s);

substantial consumption of organic reagents and solvents;

- multi-stage multi-get gold in the form of a metal of high purity.

Closest to the technical essence and the achieved result to the proposed technical solution is the method of extracting gold from the electrolyte for electropolishing of products containing halide compound ion gold, which in the electrochemical processing of gold-containing etching solutions.(see A.S. USSR №571527, IPC SS 1/20, bull. Image. No. 33, publ. 05.09.77 year).

The disadvantages of the prototype method are: incomplete extraction of the precious metal and the complexity of the process.

Disclosure of inventions

The objective of the invention is to develop a method of extracting gold from the electrolyte for electropolishing products, which would provide technical result - increased recovery, simplifying the process and obtaining the gold of high purity.

This technical result is achieved by the present invention offers a method of gold extraction from sulfuric acid electrolyte for electropolishing articles containing compound ion gold with tiomochevinoi, including the destruction complex by treatment of the electrolyte 33,0-67,5%nouppercase hydrogen at a concentration of sulfuric acid, equal to 0.19-0.45 mol/l, with the restoration of the gold to the metal.

According to the invention the treatment is carried out 33,0-67,5%hydrogen peroxide with stirring until the termination of allocation of bubbles of sulfur dioxide, it does not require additional heating, since the introduction of the hydrogen peroxide solution is heated to boiling. In addition, when handling electrolyte 33,0-67,5%hydrogen peroxide is not allocated in the free state sulfur, which simplifies the method of obtaining gold. If you take treatment of the electrolyte, the hydrogen peroxide with a concentration of less than 33%, the destruction complex is not observed, and if you take 33%concentration of hydrogen peroxide, the destruction of the complex will be a longer time and will be accompanied by emissions of sulphur in the free state, which complicates the process of obtaining the gold of high purity.

Feature of the proposed method of obtaining gold is the destruction of the complex compounds of precious metals with thiourea directly in the electrolyte after electropolishing and simultaneously restoring gold to metal, which eliminates the stage of evaporation, heating and Stripping. This gold is excreted quantitatively in the form of a metal with a purity corresponding to the 900-th sample.

The implementation of the invention

The following examples show the implementation is the necessity of invention.

Example 1

1 liter of the electrolyte solution after electropolishing, containing 90 g of thiourea, 20 g of N3SO4concentrated, water and gold with a concentration of 10% in the form of a complex with timesaving, treated with 33%hydrogen peroxide solution with stirring until the termination of allocation of gas bubbles of sulfur dioxide and carbon dioxide. This set of gold from thiourea is destroyed by oxidation of thiourea to SO2and CO2and ammonium sulfate, and the gold is reduced to metal with a purity corresponding to the 900-th sample.

The output of gold in the form of pure metal according to the chemical analysis was 10 g, which corresponds to 100%.

Example 2

1 liter of the electrolyte after electropolishing, containing 90 g of thiourea, 45 g of H2SO4concentrated, water and gold with a concentration of 5% in the form of a complex with thiourea, process 67.5%hydrogen peroxide with stirring until the termination of allocation of gas bubbles of sulfur dioxide and carbon dioxide. This set of gold from thiourea is destroyed by oxidation of thiourea to SO2and CO2and ammonium sulfate, and the gold is reduced to metal with a purity corresponding to the 900-th sample.

The output of gold in the form of pure metal according to the chemical analysis was 5.0 g, which corresponds to 100%.

The table shows the s dependence of the extraction of gold from the number used in the process of reagents.

MetalThe Au concentration in the electrolyteThiourea, gH2SO4(conc.), gThe time of deposition of Au, minThe output of the metal, %
Au10,090,020,050100
Au5,090,045,030100
Au7,590,025,045100
Au1.590,030,040100

Using the proposed method allows to simplify the process of quantitative obtaining gold from the electrolyte for electropolishing of products by eliminating time-consuming and labor-intensive evaporation, dissolution and additional the cleansing of the precious metal.

The proposed method can be widely used for concentration of gold from dilute solutions, recycling of precious metals in the manufacture of articles of jewelry containing gold.

Although the present invention is described by way of examples of its implementation, the scope of the present invention is not limited to these examples, but is defined only by the claims with regard to the possible equivalents.

Method of gold extraction from sulfuric acid electrolyte for electropolishing articles containing compound ion of gold from thiourea, including the destruction complex by treatment of the electrolyte 33,0-67,5%hydrogen peroxide solution at a concentration of sulfuric acid, equal to 0.19-0.45 mol/l, with the restoration of the gold to the metal.



 

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