Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
  • C25C1/20—Electrolytic production, recovery or refining of metals by electrolysis of solutions of noble metals

Definitions

• the invention relates to a process for the electrochemical refining of crude gold
• crude gold Contaminated gold, hereinafter referred to as crude gold, is particularly important in the recycling of electro-technical and electronic Bayteie.
• crude gold is a gold alloy, which consists of fine gold and admixtures of other metals. As admixtures often occur in particular copper and possibly also silver.
• US Pat. No. 4,612,093 B describes a process for recovering fine gold from an electrolytically dissociable crude gold anode. This method is characterized by a first electrolyte region with the anode and by a second electrolyte region with a (carbon) cathode. Both regions are separated by a semipermeable membrane that is impermeable to gold ions from the first electrolyte region toward the cathode.
• the electrolyte in the first electrolyte region comprises an aqueous solution with dissociated halogens and an initially oxygen-supplying additive.
• US Pat. No. 5,009,755 B likewise describes a process for recovering fine gold from a crude gold anode to be dissolved by electrosolation. This procedure also makes use of that anode-side region is separated by a semipermeable membrane from the cathode-side region.
• the aqueous electrolyte solution contains a) halogen ions, in particular dissociated ammonium chloride, which also serves to form soluble silver and copper compounds, and
• the semipermeable membrane is impermeable to ions containing gold, insoluble components and abrasive oxide particles.
• the extraction of fine gold from the gold-containing ions in the anode-side region is carried out by adding bisulfite salts.
• FIG. 1 representation for the first process step - Anodic dissolution of the raw gold
• FIG. 2 shows the second method step - cathodic deposition of simply refined fine gold
• FIG. 3 shows the third method step - anodic dissolution of the simply refined fine gold
• FIG. 4 shows the fourth process step - cathodic deposition of twice refined fine gold.
• the electrolytic refining for the production of fine gold from contaminated with accompanying elements raw gold takes place in a tub 1/2 "which is divided by a permeable for particular ion membrane 3 in a first area 1 and a second region. 2
• Each area comprises an electrode A1, K2 and an electrolyte solution E1, E2.
• As starting elements are base metals such as copper, nickel, tin and zinc or their compounds, as noble metals are silver, palladium and platinum metals or their compounds to consider.
• the anodic dissolution of the raw gold see Fig. 1, in the first region 1 acting as an anode electrode A1 made of raw gold or acting as an anode loaded with raw gold scrap anode basket or acting as an anode with raw gold scrap in Contact contact rod connected to the positive pole of a voltage source for a DC circuit.
• This anode A1 is arranged in an aqueous electrolyte solution E1 containing dissociated hydrochloric acid and / or dissociated chloride salts.
• the hydrochloric acid concentration of the electrolyte solution E1 is in the range between 5 and 15%.
• With dissociation the decay of a molecule, e.g. called a salt in its ionic constituents.
• Dissolution of common salt in an aqueous solution results in positively charged sodium ions and negatively charged chlorine ions.
• an electrode K2 acting as a cathode is connected to the negative pole of the voltage quenules and arranged in a dissociated sulfuric acid and / or dissociated sulfate salts containing aqueous electrolyte solution E2.
• the sulfuric acid concentration in the electrolyte solution E2 is about 10%
• the membrane 3 separates both electrolyte solutions E1 and E2 from each other.
• the raw gold anode is dissolved to form positively charged base metal containing cations and negatively charged gold containing anions (also called negatively charged gold complex anions).
• the membrane 3 is only permeable to positively charged cations formed in the first region 1 in the direction of the negative cathode K2 arranged in the second region 2, at which point the metal contained in the cations, optionally copper, for example, precipitates.
• anode basket of electrically conductive material loaded with raw gold scrap also comes into consideration.
• the contact between the anode basket and the crude gold scrap must be ensured.
• a Koniaktstab in contact with the raw gold scrap can be used as an anode.
• the cathodic deposition of simply refined fine gold see FIG. 2, after dissolution of the raw gold in the first region 1 according to the first method step in the first region 1 in the electrolyte solution E1, a negative electrode connected to the negative pole of the voltage source. Dene acting as a cathode electrode K1 'arranged.
• an electrode A2 which is connected to the positive pole of the current source and acts as the anode, is arranged in the electrolyte solution E2.
• the precipitation of the gold from the originally negatively charged gold-containing anions takes place at the negative cathode K1 in the first area 1 as simply refined fine gold.
• the simply refined gold has a higher degree of purity than the gold in the raw gold anode A1 or in the raw gold scrap .
• the electrode K1 in the first region 1 which is coated with simply refined fine gold, is connected to the positive pole of the voltage source in the first region 1 and into the electrolyte solution containing hydrochloric acid E1 is arranged in the second area 2 an electrode K2 ', which is connected to the negative pole of the voltage source and acts as a cathode, is arranged in the electrolyte solution E2 containing sulfuric acid,
• the simply refined fine gold adhered to the electrode AV is dissolved to form positively charged base metal-containing cations such as copper cations and negatively charged gold-containing anions.
• the membrane 3 is only permeable to positively charged cations formed in the first region i in the direction of the negative cathode K2 'arranged in the second region 2, at which point the base metal contained in the cations precipitates.
• the electrode K1 'acting as the cathode is connected to the negative pole of the voltage source and placed in the electrolyte solution E1 in the first region 1.
• the electrode A2 'acting as the anode is connected to the positive pole of the voltage source and arranged in the electrolyte solution E.2.
• the gold from the anions originally containing negatively charged gold in the first region 1 precipitates at the negative cathode K1 'as a double refined fine gold down.
• the double-refined gold has a higher degree of purity than the simply refined gold.
• the first to fourth process steps according to the invention may be followed by further process steps five and six.
• the twice-refined fine gold deposited cathodically in the fifth and sixth method step would be dissolved anodically and cathodically deposited in the sixth method step in analogy to the fourth method step as triple-refined fine gold.
• subsequent seventh and eighth process step analogous to the third and fourth or fifth and sixth process steps fourfold refined fine gold can be obtained, etc.
• the method according to the invention is preferably a example of the company lon-power GmbH,
• the inventive method is carried out at a temperature of about 55 degrees Celsius.
• the gold dissolving process steps one and three are carried out at a voltage of 5 to 6 volts with a maximum current of 30 amps; the gold depositing process steps two and four at a voltage of 2 to 4 volts and a current of 8 to 20 amperes.
• the addition of silver in the anodic raw gold reacts with the hydrochloric acid contained in the electrolyte E1: It forms poorly water-soluble silver chloride, which is reflected in particular as an undesirable solid coating on the raw gold anode or the raw gold scrap. This coating prevents or limits the contact of the electrolyte E1 with the raw gold anode or with the raw gold scrap and therefore hinders the electrolysis.
• This brittle coating provides a better contact of the electrolyte El with the raw gold anode or with the raw gold scrap and therefore does not limit the electrolysis process as much as is the case with silver chloride.
• the application of ultrasound to the raw gold anode A1 or of the raw gold scrap forms the formation of an undesirable solid coating of silver chloride on the raw gold anode or Can reduce crude gold scrap or inventively replace the only slightly adhering to the raw gold anode or the raw gold scrap brittle coating mechanically.
• the electrode A1 made of raw gold or the Rohgotd scrap (in the anode basket or in contact with the contact rod) is subjected to ultrasound.
• ultrasonic vibrator elements are available as Handeisware » mounted in a housing.
• This housing is so coupled via a chamber with the outer wall of the tub 1/2, that the exiting from the housing ultrasonic vibrations as lossless pass the filled with water or Giycerin chamber and can impinge on the anode in the tub 1/2.
• the wall of the chamber and the tub in the region of the ultrasonic vibrations passing through it consists of a material, preferably of polypropylene, which allows the ultrasound to pass through as lossless as possible.
• the frequency of the ultrasonic transducer elements used lays at 40 KHz. They have no direct contact with the electrolyte. As a source of the ultrasonic oscillator elements may be mentioned;
• resulting insoluble particles such as silver chloride or the detached from the anode of the anode particles of the brittle coating are filtered out.
• This filtering can be done for example by means of a circulation pump.
• filter cartridges No. NT 10 "(Article No.
• three titanium electrodes are used as cathode K2 in method step one and cathode K2 'in the method step.
• anode A1 in process step three as cathode K1 in process step two, as cathode K1 in process step four, as anode A2 in process step two, as anode A2 in process step four, and as anode in process step one, if it does not itself consist of crude gold, used are placed titanium electrodes.
• the anode basket for receiving the raw gold scrap consists of a mesh-like mesh made of expanded titanium expanded metal.

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• 2016
  • 2016-03-09 DE DE102016104237.4A patent/DE102016104237A1/de not_active Withdrawn
• 2017
  • 2017-03-09 CN CN201780028624.6A patent/CN109312481B/zh not_active Expired - Fee Related
  • 2017-03-09 WO PCT/EP2017/055604 patent/WO2017153547A1/de active Application Filing
  • 2017-03-09 ES ES17713591T patent/ES2811380T3/es active Active
  • 2017-03-09 PT PT177135910T patent/PT3426825T/pt unknown
  • 2017-03-09 PL PL17713591T patent/PL3426825T3/pl unknown
  • 2017-03-09 EA EA201892012A patent/EA036684B1/ru not_active IP Right Cessation
  • 2017-03-09 EP EP17713591.0A patent/EP3426825B1/de active Active

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