Precious Metal Mine
by James Wark
Member of the Houston Gem & Mineral Society
James Wark with circuit board


ld computers are a precious metal mine. That’s right—gold, platinum, silver—just to start with. Finishing up the rear, the other metals are palladium, rhodium, and tantalum. What is going on here? You threw away a computer. Seven pounds of gold computer boards equal one ounce of gold. Larger dinosaur mainframes have upward of one pound of gold boards. Let’s see: 12 troy ounces times $450 per ounce is $5400. Not bad in my opinion for a $1 investment.

“What are you talking about?” you say. “Am I missing something here?” you ask.

Well, you see knowledge is power. At government auctions, it is literally a gold mine giveaway. Sound easy? It is. Some of the mainframes weigh as much as 1400 lbs. The government has fork lifts to load your purchase for you, but be careful when you try to unload it at your destination! I remember a gentleman who hooked one up to a tree and tried to drive his truck out from under it. He pulled the back half of his truck off the frame.

Okay. After safely unloading your purchase, it is time to “demanufacture” it. First of all, check out the components that are most valuable as spare parts. This includes the memory, integrated circuits (ICs), CD-ROM drives, central processing units (CPUs), and hard drives. A hard drive from an IBM mainframe weighs 120 lbs. and has 80 megabytes of hard drive space. It’s worth $1000 to the right person. A reel-to-reel motor can be used as a wind-driven generator.

Circuit board with 2 rings, 24K ingot, and 14K ingotLet’s say that no components work. What are they worth as scrap? Metals include aluminum at 50 cents a pound, copper wire at 40 cents a pound, and iron at 2 cents a pound—chump change! Platinum is approximately $10,000 a pound. Palladium is about $3000 a pound. You get the picture. So—how do you extract the precious metals from the computer?

Take gold for instance. One part nitric acid and three parts hydrochloric acid is aqua regia, also known as “royal water.” It literally dissolves the gold off the plastic board. After using the aqua regia to dissolve the gold, neutralize the acids. Then add water and create a vacuum to pull the neutralized solution into a glass tube with a filter. The gold is in solution and passes through the filter. The particles caught in the filter are the other metals. Decant the gold solution into a steel pan, add sodium chloride, and heat the mixture to 400°F to dry. At this point, the mixture looks like brown dirt. Flux the entire interior of your crucible, add the gold, and flux the top of the gold. Melt it in a smelter at approximately 2100°F. Pour the results into a mold, and check out your 24 carat ingot after it cools. Do NOT try this at home. The fumes can kill!

Two 14K gold rings; 24K round ingot, 14K oblong ingotA second trick of the trade is to make an amalgam of mercury and gold. When mixed together, they become a paste. Cut a potato in half, and drill a hole in one of the two potato halves. Leave about an inch of potato on all sides and the bottom. Put the paste into the hole. Reassemble the potato and wire it together with copper wire. Put the potato and paste in aluminum foil and set it on a campfire for a few hours. The end result is clean mercury and a cube of gold. The mercury is easily retrieved by poking a hole in the potato and allowing the mercury to drain into a container. I can’t take credit for this method—it was developed in 1849 during the California gold rush.

A third way is to grind the computer boards into a powder, flux the crucible, place the powder inside, fire up the smelter until the material becomes a liquid, and pour it into a mold. This method produces a “dory bar.” Unless you have pure gold boards (rare), the mixture is a combination of precious metals and will have to be assayed. In this situation, plan to divert enough B.B.s from the pour to take to your assayer for analysis. They pay on the percentage of precious metals.

Another use I have found for old computers is their use on movie sets. Last year I rented some main frames to a movie called Mr. Hell. I was paid to move the main frames and then to set them up for a lab. Rental was by the week, and I collected a bonus for being on the crew. This has opened up a whole new business for me. Need a computer for a commercial?