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Comment by analog31 | Hacker News Reader

One problem with gold recycling is that some simple methods are also phenomenally harmful to both workers and the environment, as they involve dissolving the gold with mercury. From what I've read, some of this stuff gets shipped to countries with relatively weak labor and environmental laws.

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Simple fact, Mercury does not dissolve gold. It amalgamates with certain metals making them easier to collect in one mass rather than having tiny bits all over the place. Mercury use has very little to do with gold mining or recovery today. Repeat: I said it's used very little- not that it is never used. Its much easier and more economical to just use aqua regia to get the gold away from the base metals. Gold recovery from electronics is done in semi- laboratory conditions and the gold is refined using the same conditions which are a far cry from some guy in the hills digging up dirt and spilling his waste into a mountain stream. Modern refiners shun Hg. It's hard to clean up the waste to acceptable levels. That's a big deal nowadays. No one wants to poison the environment. Acid based extraction techniques are much cleaner,easier and more environmentally friendly. Just like everything else- it comes down to profits and it's just more profitable to use acids instead of Mercury. Hell it's even more profitable to use cyanide to extract the gold. I know a little bit about this stuff- AMA?

The mercury used in that process is generally recycled in a closed loop; if it's done properly, dangerous levels don't get into the workers or the environment. Metallic mercury is the least dangerous form of mercury, less toxic even than the ores mercury is mined from.

Unfortunately with high gold prices it becomes profitable to run small operations that don't meet the same standards. Currently it is believed that 1/3 of all mercury pollution comes from illegal gold mining [0].

[0]:https://www.amazonconservation.org/pdf/gold_mining_fact_shee...

But it's often not done properly, which is there are quangos and NGOs trying to get people to move to different methods of gold extraction.

UN: https://www.youtube.com/watch?v=WUY4CV50VQo

You're right that mercury metal isn't a such a big problem. The problem is that people are heating it and breathing the vapours.

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