How to Refine Gold/Gold Jewelry/Gold Parting Process
Before explaining the process of refining the scrap gold jewelry, I think, it is necessary to tell you a little bit about the purity of gold used in making jewelry. So that you know about what metals you are dealing with while refining gold. The pure gold jewelry is very rare. Gold is a soft metal. So, if you make jewelry from pure gold, it may not be more durable. It could be deformed. So, to make the gold little harder and the jewelry more durable, copper, silver or some other metals are mixed with it. The purity of jewelry is measured in karats. 18 karat jewelry means 75% gold and 25% other metals.
Use reliable safety equipments while refining gold. Always wear goggles and gloves, etc. Always use commercial grade nitric acid, don’t use the lab grade. Commercial grade nitric acid has a concentration of 68%. For refining gold jewelry scrap, we take one part of gold scrap and two parts of silver that is for 100 grams of jewelry scrap we mix 200 grams silver with it. This is first melted and then poured into water to prepare small shots of gold alloy for its easy dissolution into the chemical. Now we take a heat resistant bottle and put the shots into it, and pour some nitric acid (HNO3) into the bottle. Copper and silver start dissolving into nitric acid, leaving the gold behind. Now we take one iron plate and keep it on a stove with low flame. Now keep the bottle on this iron plate.
The heat will make the reaction stronger in the bottle, and more smoke will start coming out of it. The room should be properly ventilated or preferably with an exhaust fan. Let the acid boil gently till all the shots have completely dissolved. If the reaction stops, and some shots are still lying on the bottom of the bottle, you can pour little more nitric acid into the bottle. And keep doing it till all the shots have dissolved completely. Now, turn off the stove and remove the iron plate and the bottle from it. Keep the iron plate on the floor, and keep the bottle on this iron plate and let the gold dust settle to the bottom for a few minutes. Now decant the solution from the bottle carefully keeping the gold dust in the bottom of the bottle. Wash this gold dust two to three times with plain tap water. Dry it and melt it. Now you have got 24 karat gold.
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