Video summary

Electrolytic Gold Cell Part 2

Main summary

Key takeaways

Educational

Main ideas / lessons conveyed

  • The creator continues an electrolytic gold refining series, aiming to run a working cell long enough to deposit high-purity gold onto a cathode.
  • Instead of using a thin/rolled gold cathode, they test a titanium cathode (described as a “turbine blade”). They do this because they’re unsure about impurities in another gold piece/alloy and want to confirm the process still deposits gold effectively.
  • They stress that welding/soldering parts for the anode suspension is best left to a professional. Soldering the suspension to the gold bar needs concentrated heat and can fail easily.
  • The process depends heavily on proper electrolyte prep and cell operating conditions, especially:
    • filtering the electrolyte,
    • controlling temperature (following “the book” targets),
    • controlling voltage/current (starting around ~1.5 V, then increasing experimentally),
    • maintaining electrolyte level to prevent dissolving the anode attachment (the “dog ears”).

They also observe how increasing voltage/current affects results:

  • Cathode appearance changes (e.g., “sparkly specks” vs. nodular deposits).
  • Anode dissolution accelerates; at higher current the anode can “dissolve away” faster and the attachment may fail.

After electrolysis, they emphasize rinsing and gold recovery:

  • Physically removing deposited gold from the cathode (a hard crust forms on titanium).
  • Using sodium metabisulfite to precipitate remaining gold from the electrolyte.

Methodology / step-by-step procedure

1) Set up anode/cathode materials

  • Anode
    • Use a double-refined pure gold bar as the anode.
  • Anode suspension
    • Use two 14k scrap gold rings.
    • Cut them apart.
    • Have a jeweler weld the pieces onto the anode bar to create attachment points (“dog ears”).
    • Bend the welded “dog ears” so the anode can hang on the beaker edge.
  • Cathode
    • Choose a titanium cathode for testing (titanium acts as the test cathode material).

2) Prepare electrolyte (from Part 1)

  • Use the electrolyte described earlier as a gold chloride solution.
  • Filter the electrolyte before use.
  • Perform a mock electrical setup first:
    • Connect power supply polarity correctly:
      • Red bleed = positive lead → to the anode bar.
    • Confirm the cathode can protrude properly into the cell.
  • Assemble and load the cell:
    • Use a 150 mL beaker with a magnetic stir bar.
    • Add electrolyte until it sits just below the attachment level, preventing contact with the welded “dog ears.”
    • Electrolyte composition previously described as containing ~25 g of gold dissolved in aqua regia.

3) Adjust electrolyte composition and temperature

  • Add hydrochloric acid to reach the needed condition:
    • Mentioned as about 10% free hydrochloric acid.
  • Heat while monitoring temperature:
    • Start around 127°F / 53°C.
    • Increase toward the “book” target: 140°F.
    • Operating temperatures reported:
      • around ~134°F at one point,
      • later ~142–144°F during the run.

4) Start electrolysis (initial operating point)

  • Ensure the power supply starts at no current (fully down).
  • Energize gradually:
    • Voltage around 1.6 V (example current ~4 A).
  • Observe the process:
    • Expect blackening on the cathode and visible gold formation (nodules).
    • The anode begins corroding and shrinking over time.

5) Mid-run adjustments (conductivity and performance)

  • If current (amps) drops:
    • Add small amounts of electrolyte and/or a few drops of hydrochloric acid to improve conductivity.
  • Keep temperature within the operating range (e.g., ~142°F then ~144°F later).

6) Experimental voltage increases and their effects

  • Increase voltage/current to see how deposition changes.
  • Example attempts mentioned:
    • ~2.1 V (current jumping to roughly 4–6 A).
    • A later attempt pushing toward much higher current (aiming around ~7 A), with warnings it can be too high.
  • Observable effects:
    • Higher voltage/current changes cathode texture/appearance (more “sparkly specks” vs earlier nodules).
    • Higher current increases anode loss rate:
      • anode dissolves faster,
      • attachment can fail (“no longer clipped onto the edge”), likely due to weight reduction.

7) End electrolysis and perform separation/cleanup

  • Turn off:
    • heat,
    • stir bar,
    • power supply.
  • Remove:
    • the anode (before it falls in),
    • the cathode with plated gold.
  • Rinse the cathode to remove electrolyte residue.
  • Gold removal considerations:
    • On a titanium cathode, deposited gold forms a hard crust that is difficult to remove.
    • Use mechanical tools (e.g., bamboo skewer, later a stainless steel spoon) to break the crust and detach the plated gold.

8) Recover gold from remaining electrolyte

  • Pour remaining electrolyte into a larger container.
  • Add sodium metabisulfite (“stump out”):
    • Add about a spoonful.
    • Goal: precipitate remaining gold.
  • Retrieve the precipitated gold (quantity reported approximately).

9) Final melting / produce ingots

  • Melt collected electrolytically refined gold into an ingot (noted as final purification via electro-deposition).
    • Example: 45.6 g ingot mass from plated cathode material.
  • Additional gold sources mentioned:
    • ~57 g from gold rolled earlier for an “ammo bar” attempt,
    • ~25–30 g from precipitated electrolyte.

Speakers / sources featured

  • The video creator / narrator (first-person “I” throughout).
  • “My jeweler friend” (named only as the professional who welds anode suspension components).
  • “The book” (referenced for target operating parameters such as temperature and voltage guidance).

Original video