Q&A for How to Remove Gold from Circuit Boards

Yes, most cell phones have gold in them. Places where gold may be found in a cell phone include the speakers (gold plated parts), the circuit board and small parts such as gold-plated connector pins and capacitors.

This depends on the amount of gold in the phone but a rough estimate is around USD$1 to USD$2 per phone. While it may not seem like much, by the time a gold recycling company has a ton of phones, that adds up to a lot of gold. For example, Sims Recycling Solutions North America recycled 167 ounces of gold from used cell phones in 2014, the equivalent of about 789 gold medals (Silverberg, 2017).

Precious metals are found in a number of places in a computer, including the printed circuit board, the CPU (computer chip), the hard drive, the capacitors, the connectors, etc.

Many electronic devices contain a small amount of gold, especially on the circuit board. This is because gold is a highly efficient conductor (better than copper) and it does not corrode, ensuring therefore that no interruption occurs in transmitting voltages and currents needed to run the device.

Hydrochloric acid can be used but will take longer than nictric acid. Aqua regia would be the most efficient way to do it but you would have to precipitate the gold out of the solution.

If you mean hydrochloric acid and hydrogen peroxide, yes, but it will take a lot longer.

I will not be pure at all. There will be a lot of ash and all kinds of char everywhere. The 'purity' solely will depend on how well you are able to mechanically separate the gold from all the other garbage. Considering that most of the gold layers are very thin, you will probably have a hard time trying to separate it.

See How to Melt Gold .

Nitric acid will dissolve silver, but to dissolve platinum, you need aqua regia. Palladium can be dissolved by both.

Hydrochloric acid can be used, but it will take longer than nitric acid. Aqua regia would be the most efficient way to do it, but you would have to precipitate the gold out of the solution.

When using acid it will take care of the metal, not the plastic. So when you add acid to the cable, you will convert your copper metal to solution and leave the plastic only.

Depends on which metals you are talking about. Nitric acid dissolves copper, iron, lead, tin, and many other metals. Only gold, platinum, and iridium can resist nitric acid, and only iridium resists aqua regia.

Theoretically, you could. However, there are issues with that: first of all, when scraping, you will also scrape off a lot of the base material that the gold was deposited on. Other than that, the gold layer is usually VERY thin. Considering that, you'd need to scrape ridiculously carefully to scrape just the gold. The gold is thin, but still more durable than the material under it. During scraping, it's easy to scrape a lot of the base material too, which you want to avoid.

No, do not dilute the nitric acid. Doing so would weaken it.

Let it cool some, then, while wearing industrial gloves, break off the remaining plastic. Try not to let it get too cold.

Do not pour it down the drain or anywhere else, for that matter. There is really no safe way to dispose of it.

Yes, but it is time-consuming unless you using with hydrogen peroxide. Gold is layered on top of copper. Nitric acid is the best oxidizing agent for copper.

Yes, in fact sulfuric acid is a stronger acid, and it is also cheaper, so I do believe you can.

It will cost a lot of money, much more than the resulting gold sells for. The gold costs about 13 dollars per computer. It may sound like a lot, but it really isn't.

Muriatic acid is hydrochloric acid diluted to 10% (for reference, household vinegar is 5-8% acetic acid for comparison). So yes, it's the same substance just with 90% water and 10% HCl in the solution.

Nowhere. Anywhere that buys gold will want it in its solid form. Let it cool off before attempting to sell it. As for solid gold, there are plenty of "We buy gold and silver" places in most larger cities, as well as online.

Nitric maybe a couple of hours. If this is your first time, use hydrochloric (muriatic acid), and add bleach into acid with a dropper until it stops fizzing as much and stir. Then give 30 minutes out in direct sunlight, which helps break down chloride. Use a mask when doing this mixing, as any acid with bleach produces chlorine gas, which is deadly. Then after 30 minutes in sunlight, filter it. And just have the solution. Add Bovide brand Stump-out stump killer to turn the gold solid (precipitating) again. Filter and it should have brownish mud material in bottom. Dry to dirt or dust, put in crucible, spritz lightly with water. Burn, and as it melts, sprinkle borax on the crucible and pour into the mold.

Neutralize it and dump it out if it does not contain dissolved metals. It will just form sodium or potassium nitrate (depending on what base you use), which is not harmful to the environment. If the acid contains dissolved metals you can try making it alkaline since most metal hydroxides are pretty insoluble. Filter off the solids and then neutralize the liquid and dispose of it as above. The solids are trickier to dispose of. It very very much depends on what metals they contain.