A. GOLD REFINING STEP BY STEP INSTRUCTIONS For every ounce of scrap gold you are going to refine you will need a capacity o f 300 milliliter container for the aqua regia solution. Place impure gold to be dissolved into a glass or plastic container. Aqua regia - Mix one part nitric acid to 3 parts hydrochloric acid. OR To the container, add 30 milliliter of nitric acid for every ounce of metal. To the container, add 120 ml of hydrochloric or muriatic acid for every ounce of metal in the container. Allow impure gold to dissolve for an hour to overnight for complete dissolution. Once all gold is dissolved, filter out any particles out of the acid solution co ntaining the liquified gold into another glass container using a fine stainless strainer. The remaining particles should not be discarded as these may contain o ther precious metals! The acid containing the dissolved gold will be an amber to emerald green color d epending on the purity of the gold and should be clear (not murky or cloudy). If the acid solution containing the dissolved gold is murky, it may contain partic les and should be re-filtered with a finer grade paper filter. Slowly, add the water/urea (urine ) to the acid solution containing the dissolve d gold. The acid solution containing the dissolved gold will foam with the addit ion of the water/urea (urine). Do not add the water/urea (urine) so quickly that the acid foams out of its container. When the acid solution containing the diss olved gold stops reacting to the addition of water/urea (urine), stop adding the water/urea (urine). You've just raised the pH of the acid from 0.1 To 1.0, kill ing the nitric acid but not the hydrochloric. Add precipitant ( sodium bisulfite ) slowly in minute amounts to the acid soluti on containing the dissolved gold, immediately the acid solution containing the d issolved gold will change to a muddy brown appearance as brown particles of gold form in the solution. Occasionally agitate the solution with a glass stir rod, as the brown particles continue to form they will sink to the bottom of the cont ainer, this brown "mud" is, despite its appearance, pure gold. Allow precipitant ( sodium bisulfite ) to fully draw out all the gold out of the solution, test for gold in the remaining solution, if it tests positive for gol d, you may have to add more precipitant ( sodium bisulfite ). To test the solution for remaining gold, first immerse the end of the stirring r od in the acid. Remove it and touch that end to a paper towel to make a wet spot . Put a drop of gold detection liquid on the wet spot on the paper towel. If any gold is still dissolved in the acid, the wet spot will turn a purple-black or a purple-brown. If you see this color change then give the precipitant more time to work and/or add more precipitant. Now all the gold should be drawn out of the solution and the acid should now be a clear amber color with a brown mud settled at the bottom. Using a fine paper filter, pour off the acid into another container allowing the mud to stay in the filter. The mud is pure gold. When all the acid is poured off, return the mud to a container for rinsing, add tap water to the mud. Stir and let the mud settle. Using a fine paper filter, po
ur off the tap water into the container with the acid. Do not pour off any parti cles of brown. Repeat this rinsing 3-4 times or more. After completing the final tap water rinse, rinse once again with aqua ammonia ( %10 ammonia to %90 distilled water ) white vapors will appear. The aqua ammonia cleans impurities from the gold mud while, at the same time, it neutralizes any acid still clinging to the gold mud. While in the fine paper filter, give the mud on last rinse, this time with disti lled water until mud and filter is clean. Take filter with clean gold mud and gently squeeze of any excess water and place filer with mud into crucible for melting. Once melted, the gold will again take on the appearance of metal. If you've foll owed the instructions carefully and used filters, the gold will be 999.5 % Pure with virtually no losses. Platinum- If you had platinum in your gold, it will not dissolve, to any appreci able degree, in the room temperature aqua regia. It will be left behind when you pour off the aqua regia, prior to precipitation. To insure high purity of the p latinum, you will need to re-refine this material. Put this material in a fresh aqua regia bath. This time, however, heat the acid to simmering. Continue heatin g until all the platinum is dissolved (that may take 1-2 hours). When completely dissolved at 1 ounce of ammonium chloride for every ounce of dissolved platinum . The platinum will precipitate as a red mud. If you want to leave the iridium i n the platinum, then wait for it to precipitate before recovering the platinum. Iridium will precipitate as a blue-black mud after the platinum precipitates. Pl atinum group metals will also show up on the stannous chloride test. Platinum tu rns red, palladium Palladium turns orange and iridium turn blue-black.
