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INVENTION
Russian Federation Patent RU2181780

METHOD OF EXTRACTION OF GOLD GOLD POLYMETALLIC MATERIALS

METHOD OF EXTRACTION OF GOLD
MATERIALS OF GOLD POLYMETALLIC

Name of the inventor: Zozulya Vladimir (UA); Pertsov NV (RU); Prokopenko Vitaliy Anatolyevich (UA)
The name of the patentee: Nikolai V. Pertsov (RU); Zozulya Vladimir (UA); Prokopenko Vitaliy Anatolyevich (UA)
Mailing address: 01023, Kiev-23, st. Caves descent, 8, kv.72, NV pepper
Starting date of the patent: 2000.03.06

The invention relates to the production, recovery or refining of metals by electrolysis. Processed material, previously melted and molded, used as an anode and conduct electrochemical dissolution and deposition on the cathode-metal impurities and the recovery of gold in the form of anode sludge. The content of gold in the anode material is provided in the range of 5-50 wt. % And the electrolysis process is carried out in an aqueous acid solution and / or a salt with an anion of NO 3- or SO 4- concentration of 100-250 g-ion / l at the anode current densities 1200-2500 A / m 2 and a bath voltage of 5 12 B. The method allows for simplification technology to ensure high performance of the recovery and purity of allocated gold.

DESCRIPTION OF THE INVENTION

The invention relates to the processing of gold polymetallic materials to extract gold, and particularly, to a process for extracting gold from its alloy with other generally non-precious metals, and can be used for processing metal scrap: scrap jewelry and other waste jewelery, coin scrap, native gold, gold-bearing scrap dentures, electronic waste industry, semi-processing of gold ores with gold content over a wide range.

Known methods for extracting gold from other metals, alloys, and gold-processing technology choice of material depends on its content of and the nature of gold (nature) of the other components.

For isolation of the gold alloys with other less precious metals with gold content of 20-80% it is widely used a so-called melt-chlorination method [1], which is that in the pre-processed material is melted at T = 1423 K is fed through a graphite tube gas chlorine; formed metal chlorides impurities (. iron, zinc, lead, etc.) was removed and trapped in electrostatic capacitors; After distilling off the bulk of the impurities were removed copper and iron chlorides from the melt surface, and the selected Gold poured into the mold to obtain ingots with commodity gold content of at least 99.5% silver, not more than 0.35%.

The disadvantages of this method are high power consumption, complexity of hardware design, due to the work of chlorine in the atmosphere at a high temperature and difficulty in performing the environmental safety requirements.

For further deeper purification of gold obtained by chlorination, and for refining gold alloy it with precious metals at high content of the gold used electrolytic method which comprises the following [2] from the processed alloy manufactured anodes (composition: gold 85 -92%, 6-15% palladium, silver, 0.3-1%), which is placed in a made of porcelain and ceramics electrolyzer. The cathode plate are thin gold foil. The electrolyte is prepared by dissolving an electrolytic gold electrode in hydrochloric acid, and the gold concentration in the working solution was adjusted to 150-180 g / l, of palladium to 70-80 g / l of hydrochloric acid 100-110 g / L. The electrolysis process is conducted at a cell voltage of 0.5 V, the anodic current density providing 970 A / m 2, a bath temperature of 333-343 K and air mixing. Under these conditions, impurities dissolve at the anode and pass to the electrolyte, with prolonged use, wherein the concentration of platinum and palladium in it increases to such an extent that these metals can be identified by chemical means Gold stands on a gold cathode, which at the end is taken out of the process as a finished product high purity (gold content of 99.99%).

However, the use of this method for the recovery of gold from its alloys with base metals and containing relatively large amounts of these impurities (20%) of technically and economically impractical.

Known methods for electrowinning of gold and silver alloys at refinery producing silver. Thus, in the processing of sludge electrowinning of copper containing about 95% silver, 3% gold, and varying amounts of copper, lead, bismuth, nickel and others. Metal (so-called Dore alloy), it is melted and cast into anodes input to electrolysis [ 3, 4].

In this process, which is a technical essence the closest to the claimed anodes placed in the electrolytic cell where the cathode are titanium or steel rods, and an electrolyte - nitric acid solution of silver salts, copper and other metals contained in the alloy. When a current is passed silver anode dissolves and is deposited at the cathode, the other alloy components are accumulated in the electrolyte, and the gold enters the anode sludge, which is collected, washed and sent for further processing.

The known method solves the problem of obtaining high-purity silver (purity it sometimes reaches 99.99%) and developed process parameters provide an effective solution to this problem. Thus, by operating in the so-called electrolytic Mobius in a case [3] The electrolysis process is conducted in a neutral solution with the addition of silver nitrate to a concentration of 60 g silver / l (total concentration of NO 3- ions is 34 g-ion / l) at a voltage bath at 2.7 V and the cathodic current density of 50 A / m 2. In another embodiment (at the "Montreal East") [4] are silver refining by separating it into the electrolysis cathodes Mobius on titanium when used as an electrolyte solution of nitrate salts, Silver (125-145 g / l), copper (11-18 g / l) and lead (0.2-0.5 g / l), thus the total anion concentration of NO 3- is 90-120 g-ion / l. Cell voltage of 4.4 V, the anodic current density of 958 A / m 2.

Composition allocated in the known method auriferous slurry depends on the composition made from the silver anode and the electrolysis conditions. Obtained at the "Montreal East" auriferous slurry comprises 39-62% gold, 50% silver, 5.2% copper and 6.2% lead, and requires further processing for more complete extraction of gold, silver and other valuable metals by chemical methods, for example by chlorination in the melt.

The object of the invention is to provide a new method of extracting gold from polymetallic different kinds of materials with the technical result software - simplify the technology, a high degree of extraction and purity of gold extraction.

The technical result is achieved in the inventive process for recovering gold from polymetallic materials by electrolysis, which comprises using as an anode, previously melted and molded material being processed, electrochemical dissolution of metal impurities, followed by deposition of the cathode and the recovery of gold in the form of anode sludge and characterized that provide the content of gold in the material of the anode are made in the range of 5-50% by weight of lead and the electrolysis process using an anion NO 3 as electrolyte an aqueous acid solution and / go salt -. or SO 4- with a total concentration 100-250 g of anion-ion / liter, the anodic current density 1200-2500 A / m 2 and a bath voltage of 5.12 V.

Required gold content in the anode material (5-50 wt.%) In the presence of applicants for processing polymetallic materials with different content of gold is provided by averaging the various feedstock parties.

During the processing of alloys containing more than 50% of the gold, you need content in the anode material provides an introduction into the melt additive correction.

As a corrective additive should be used copper, zinc, nickel, silver or an alloy of these metals, taken in any qualitative and quantitative ratio.

Economically, it is advisable to use as a corrective additive cathode slurry electrolysis process of previous batches of processed material.

Below, specific examples of the invention (see., And data table) shows that the regulation of the electrolysis process parameters within the limits specified in the claims, and ensuring a gold content of the anode material in the range of 5-50% is achieved an effective removal of trace metals and recovering main mass of the cathode. When the anode is converted to a slurry with a gold content of not less than 93%, with the remaining impurities in it can be easily removed by washing first with concentrated acid followed by water, and the resulting gold bullion has a high degree of purity.

This provides a simplification of the process compared with the method of chlorination in the melt, and in comparison with the technology provides for the use of electrochemical methods known in which the same result can be achieved only with more complex chemical processing auriferous slurry obtained.

Consequently, the problem is solved with the achievement of the desired technical result.

The following are specific examples of the method.

example 1

The process of extracting gold from gold-bearing polymetallic material carried on the pilot plant, consisting of an electrolytic cell is connected to a DC power source, a chemical reactor for slurry wash, drying oven and an induction melting furnace.

The electrolyzer body is made of vinyl plastic, it has a rectangular shape (length 700 mm, width 350 mm, height 400 mm) and equipped with a tight lid. The cathode is made of stainless steel in the form of a rectangular 1 mm thick sheet and the area of 4 dm 2 mounted on the cathode rod.

To carry out the electrolysis process from the prepared anode material is cast in the form of two plates weighing 2-2.5 kg and a size 140x15x250 mm each, which are suspended in the electrolytic cell to the anode rod with hooks made of stainless steel. When this anode plates placed in special bags made of chlorin tissue and for the collection of the anode sludge.

Received for processing the material is melted in an induction furnace. If the content of gold exceeds 50%, the melt additive is added in an amount of correction required to reduce the gold content of 35-45%. The resulting gold alloy containing 5-50% is cast in the mold to ensure receipt of anode plates above dimensions, which is used in the electrolysis process.

In this example, processing to extract gold jewelry scrap is subjected to the process of production of the following composition (wt.%): 10.5 Gold, Copper 45 Nickel 25 Zinc 15 silver 4.5. Scrap is melted and cast into anode plates thereof, which are placed in an electrolytic cell as described above. The electrolysis process using a lead source as the electrolyte an aqueous solution of nitric acid with a concentration of 150 g / l under the following conditions:

  • operating electrolyte composition: copper 90 g / l, nickel 40 g / l, zinc 26 g / l of silver 8 g / l, the total anion concentration of NO 3- 150 g-IOI / l;
  • cell voltage 5.5 V;
  • Anode current density 1500 A / m 2;
  • the current strength in the bath 80 A;
  • electrolyte temperature of 343 K.

During electrolysis occurs anodic dissolution of metal impurities and their subsequent deposition onto the cathode as a fluffy cathode slurry. The process is conducted until complete destruction of anode plates (in this example 65 hours). The resulting anode slurry with a high gold content is collected in the anode bags.

After completion of the process accumulated on the cell bottom cathode slurry is removed from the cell and fed to the tank drives and anode mud is removed from the bags, rinsed in a chemical reactor first with concentrated nitric acid at a temperature of 373 K, and then with water, dried in an oven and fused in bars in an induction furnace.

example 2

In the apparatus described in Example 1, performed from a waste recovery of gold jewelery production the following composition (wt.%): 58.5 gold, copper 33.5 silver 8.0.

The waste is melted and to adjust the melt composition is added jewelry production waste of the following composition (wt.%): 33.3 gold, copper 50.0 silver 16.7 in an amount to provide the following contents of components in the anode material (wt.%): gold 40.5, 44.5 copper, silver 15.0. The alloy was cast in molds and used in the electrolysis process as described in Example 1.

Terms of the electrolysis process:

  • freshly prepared electrolyte composition: aqueous solution of nitric acid concentration of 200 g / l;
  • operating electrolyte composition: copper 80 g / l silver 15 g / l, the total anion concentration of NO 3- ion 200 g / l;
  • cell voltage 8 V;
  • amperage 90 A in the bath;
  • Anode current density 1700 A / m 2;
  • electrolyte temperature of 363 K.

The process is carried to full actuation of the anode, which in this example was 40 hours. Next, slurries were recovered and processed as described in Example 1.

example 3

Recycling waste is subjected to a jewelery production the following composition. %: 58.3 gold, copper, 22.0, 15.0 nickel, zinc 4.7. The waste is melted in an induction furnace and an anode material for the desired composition is added to the copper melt, providing an anode material the following composition, wt.%: 40.8 gold, copper, 42.6, 13.2 nickel, zinc 3.4. Further produce anodes and lead electrolysis process as described in Example 1.

The main parameters of the electrolysis process:

  • freshly prepared electrolyte composition: an aqueous solution of sulfuric acid concentration of 150 g / l;
  • operating electrolyte composition: copper 100 g / l, nickel 30 g / l, zinc 10 g / L. total anion concentration of S0 4- ion 150 g / l;
  • cell voltage of 8.5 V;
  • amperage 95 A in the bath;
  • Anode current density 1850 A / m 2;
  • electrolyte temperature of 363 K.

The process is carried to full actuation of anodes (in this example 40 hours). Next, slurries were treated as described in Example 1, except that the anode slimes washing is carried out in concentrated sulfuric acid and then with water.

example 4

Recycling the product is subjected to cementation with zinc cyanide gold-containing solutions obtained by cyanide leaching of gold ore, with the following composition, wt%: gold 51.3, 38.7 zinc, nickel, 4.5, 2.9 silver, iron - 2.6.. The starting material is melted in an induction furnace and an anode material for the desired composition is added to the melt cathode slurry obtained in the process of Example 1, the composition of which is shown in the table, providing the following ratio of the components in the anode material, by weight. % Gold 36.4, 32.7 zinc, copper, 14.5, 11.6 nickel, silver, 4.2 iron 0.6.

From the resulting alloy manufactured anode plates and lead electrolysis process as described in Example 1. Main parameters of the electrolysis process:

  • freshly prepared electrolyte composition: aqueous solution of nitric acid concentration of 200 g / l;
  • operating electrolyte composition: zinc 90 g / l copper, 15 g / l, nickel 12 g / l, 5 g silver / l, 1 g iron / l, the total anion concentration of NO 3- ion 200 g / l;
  • cell voltage of 8.4 V;
  • amperage 85 A in the bath;
  • Anode current density 1600 A / m 2;
  • electrolyte temperature of 363 K.

The process was stopped after the complete actuation of the anodes - 36 hours. Slurries were recovered and processed as described in Example 1.

example 5

Recycling waste is subjected to jewelry production of the following composition, wt.%: 33.3 gold, copper, 46.5, 13.2 nickel, zinc 7.0. The waste is melted in an induction furnace and cast into anode plates are electrolysis process as described in Example 1.

The main parameters of the electrolysis process:

  • freshly prepared electrolyte composition: CuSO 4 aqueous solution, the concentration of 200 g / l;
  • operating electrolyte composition: copper 50 g / l, nickel 10 g / l zinc 5 g / l, the total concentration of the anion SO 4- ion 150 g / l;
  • cell voltage of 10.0 V;
  • the current strength in the bath 80 A;
  • Anode current density 1500 A / m 2;
  • electrolyte temperature of 363 K.

The process was stopped after the complete actuation of the anodes - 60 hours. Slurries were recovered and processed as described in Example 3.

example 6

In this example, processing to recover gold scrap is subjected to the process of jewelry production of the following composition (wt.%): 37.5 gold, copper 46.5, silver 6.0. Scrap is melted, it is cast into anode plates of lead and the electrolysis process as described in Example 1.

The main parameters of the electrolysis process:

  • freshly prepared electrolyte composition: KNO 3 aqueous solution, the concentration of 200 g / l;
  • operating electrolyte composition: copper 30 g / l of potassium, 60 g / l Silver 10 g / l, the total anion concentration of NO 3- ion 120 g / l;
  • cell voltage of 10.5 V;
  • amperage 72 A in the bath;
  • Anode current density 1300 A / m 2;
  • 365 K. The temperature of the electrolyte

The process is carried to full actuation of anodes (in this example 65 hours). Slurries were recovered and processed as described in Example 1.

Characteristic slurry composition of the electrolysis process, the degree of extraction and the quality of the gold in Examples 1-6 are listed in the table clearly confirm the effectiveness of the claimed method.

USED ​​BOOKS

1. MA Meretukov, AM Orlov - "Metallurgy of precious metals", Moscow, Metallurgy, 1991, page 354..

2. Ibid, pp. 355-356.

3. Ibid, pp. 343-344.

4 Ibid, pp. 347-348, 356.

CLAIM

1. A process for extracting gold from gold electrolysis polymetallic materials comprising using as the anode and a pre-molten molded material being processed, electrochemical dissolution of metal impurities, followed by deposition of the cathode and the recovery of gold in the form of anode sludge, characterized in that the content provide gold in the anode material in the range of 5-50 wt. % Lead and the electrolysis process using as electrolyte an aqueous acid solution and / or a salt with an anion of NO 3- or SO 4- anion concentration at a total of 100-250 g-ion / l, the anodic current density 1200-2500 A / m 2 and a cell voltage of 5-12 V.

2. The method of claim. 1, characterized in that the desired gold content in the anode material provide different averaging feedstock batches.

3. The method of claim. 1, characterized in that when processing polymetal material containing more than 50% of gold necessary in the gold content of the anode material provides introduction into the melt additive correction.

4. The method of claim. 1 and 3, characterized in that the additives are used as correction silver and / or copper and / or zinc and / or nickel and / or alloys of these metals, combined in any proportion.

5. The method of claim. 1 and 3, characterized in that the additives are used as correction cathodic electrolysis slime previous batches of treated material.

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Publication date 14.03.2007gg