GOLD RECOVERY

In the New Scientist for April 2024, there appeared this article on a way to recover gold from electronic “wastes”: Read article.

What do you think? Does it make sense? This is written in 2024. In 1978, while running Zero Waste Systems Inc., I learned what was happening with gold recovery among the microchip and circuit board manufacturers.

Unlike the claim of this article, that e-waste costs nothing, presumably because it is “a waste” which the writer thinks no one can value, the manufacturers were exquisitely aware of the inherent gold value of circuit boards which were unusable but had gold plated electrical contacts. They would cut off the strips with the contacts, mix them up and send them out to two or three “refiners”. These were garbage companies with the usual lack of sophistication. They would burn off the plastic parts in furnaces (creating all kinds of toxic fumes which went into the air) and hope to be left with copper and gold. Then they would dissolve the gold and copper in aqua regia (a mixture of nitric and hydrochloric acids as reported in the article), filter off the remaining carbon and other solids, reduce the metallic salts to metals and use the classic methods of refining gold ore to create lumps of gold like that shown in the article. These were crude, expensive methods, intended to separate gold from dirt, in ore. Note that they had pure gold (the contacts) and they turned it into dirty gold in order to recapture pure gold again. As I said above, they were very unsophisticated. Then each refiner would submit their percentage of recovery to the manufacturers and the manufacturer would assume that the refiner with the highest recovery was the most honest (since all the refiners had been given batches with the same percentage) and would hand the really large, bulk batch to that refiner.

Of course all the refiners knew what was going on and so they would arrange among themselves just what percentage they would report. Sometimes one, sometime another would report the highest, never more than 35% of the real value, and they would share the work among themselves. They would keep the extra gold as a gift to themselves and return the low output value to the manufacturer (who probably also knew the game and found ways to game the system too).

I learned what was going on and decided to play it smart. I knew that every gold contact was plated on top of a copper base. All I had to do was dissolve the copper with ordinary nitric acid (no aqua regia) and the gold contact would float off. No burning, no crucibles, no toxic gases, no losses. The method worked like a dream. We just skimmed off the floating gold contacts and melted them into a lump to return to the manufacturers. I figured we would quote the manufacturer an honest return and capture all the business. Which we did for a while. until I realized that we were storing lumps of gold, the knowledge of which would inevitably get out and result in our lab being burgled. Probably at gunpoint. So we gave up the business. But it worked great. Unlike the article assumes, we didn’t need any aerogel, any milk whey, any aqua regia. We just used chemical intelligence and common sense, which was the combination that we used for all of our projects.

You won’t hear much about our work in an article. The thrust of contemporary reporting on “wastes” is always about the least efficient methods, usually referred to as recycling, even when they involve multi-million dollar plants that will recover plastics in various ways. The plants are excitedly announced, but you will not read about it when the funding collapses or the plant closes, as it usually does. The purpose of the push for recycling is to shift the burden of “waste management” away from the manufacturer and onto the shoulders of the public. And its working great for them.