Separating Gold & Nickel to Make Pure Gold

Nitric Acid Method

• 1

  Add dilute nitric acid to granulated gold-nickel alloy in a beaker. Stir the contents with a glass rod and allow them to react. Heat the solution on low heat to promote the proper dissolution of nickel in the acid. Add more nitric acid if the bubbles cease to form, until the reaction stops completely.

• 2

  Allow the contents to cool. You will notice small particles of gold in the solution, at the bottom of the beaker.

• 3

  Filter the solution using a funnel and filter paper. The gold particles will remain on the filter paper. Wash the particles in cold, running tap water to remove any acid and sludge on their surface.

Wohlwill Process

• 4

  Prepare an electrolytic cell by adding 1 to 1.5 troy ounces of gold to 1 liter of 5 to 7 percent hydrochloric acid, in a porcelain vessel. Then suspend a thick, pure gold foil into the solution. This is your cathode. The gold-nickel alloy block that you want to purify is the anode. The dimensions of the gold foil depend on the depth of your porcelain vessel and the size of the gold-nickel alloy block. The electrodes should completely dip into the solution.

• 5

  Use a car battery to pass electrical current through the electrodes. Attach the crocodile clip on one end of a copper cable to one of the terminals of the battery and the clip on the other end to the anode electrode. Use another copper cable with crocodile clips to connect the second battery terminal to the cathode electrode. The electric current drives a non-spontaneous chemical reaction that separates gold from nickel. The gold particles are deposited on the pure gold cathode.

• 6

  Stop the electric current once the anode or the gold-nickel alloy has completely dissolved. Remove the pure gold cathode, and rinse it in running tap water to remove the residual acid before use.