Iron Ring (TV series)

Transcription

hi everybody in this video I will demonstrate how to recover the gold plating from connector edges AKA - "fingers". the fingers are found in most the fingers are found in most scrap computers and servers warning the process shown in this video involves highly corrosive acids and should only be done outside or in a fume hood using safety gear such as gloves goggles and a respirator is mandatory let's begin the fingers are placed in a plastic strainer here we have some hydrochloric acid a little bit up copper chloride solution and a small DC powered your bubbler the plastic to goes under the strainer with the fingers right at the center now the fingers are covered by the acid and the copper solution and some water to make sure all the fingers are covered by the solution turn on the bubbler and that's it for the next week or so so here we are twenty-four hours later the solution color turned olive green and doesn't seem like much has happened let's kill the air and see what's going on NICE... we can clearly see some gold foils floating around seems to be working well cover plate is placed back on and the air tube is connected here we are again forty-eight hours into the process the solution colors now very dark green in here we can clearly see that some of fingers have been completely dplated day 6 seems like the majority of the gold plating is now loose let's keep it in the solution one more day just to make sure now you might ask yourself what exactly is going on in this process and every common printed circuit board there's basically three layers of metal plating copper nickel in gold the point is to slowly etch away the copper and nickel to free the gold layer. to be honest chemically speaking the copper chloride etching system is quite complex. however there are three simple things that will push this process forward and are important to remember: first is having free hydrochloric acid second is the presence of copper ions in the solution and the third is dissolved oxygen. maintaining these three parameters will ensure the aging process will continue on the next batch of fingers. here we are in the seventh day it's time to recover the gold falls from the solution and what's left on the fingers. I'll let the main solution with the majority of the gold oils settle for a little while and begin to wash the fingers and collect the coils that are still hanging on the fingers. the fingers in the strainer are washed with plain water in a five gallon bucket. This will take a while you probably get the point just shake until all the gold falls off. Let's fast forward we still haven't finished with the fingers, it is now set aside to dry completely will return to that later. And now for the main better gold foils. After settling for a while the bulk of the etching solution is filtered first by pouring just the solution on top. You could see the filtrations flow-rate is quite fast. and here's our recovery product nice and shiny gold foils the etching solution is moved to storage and will be reused on the next batch the foils from the fingers wash is now added to the main batch of foils now the bulk of the foils and powder are drained filter. The filter and the foils are placed in a regular open mouth beaker which is placed on top of a hot plate The gold foils and filter are now covered with a diluted hydrochloric acid half water in half acid the plate is turned on to medium heat and the beaker is covered with a watch glass now that the solution is quite hot the addition of concentrated nitric acid begins. There's about three milliliters of nitric in this pipette. this is enough to complete the task at hand. As the acid is added we can clearly see an immediate reaction. Hot aqua regia his so corrosive that aside from dissolving the gold foils it will also disintegrate the filter paper down to a pulp. By the way remember the fingers we set out to dry? Well, once they're dry we can squeeze out a little bit more gold than we got earlier just shake it hard !!! See that gold...? this goes into the aqua regia solution as well Here we can see the gold-bearing solution and the pulp settled to the bottom of the flask. The gold-bearing solution is filtered one last time to get rid of the pulp and any other solid particles Let's flute the filter real quick... And wet it... the pulp and the solution is poured into the filter and allowed to drain all the way through. When all of the original gold solution has been drained, and the filter and the pulp are washed several times until it becomes white again. The gold solution is now ready for the rest of the refining steps such as reduction up the gold, washing it and melting it the steps are already covered by my other videos so just click on these boxes below to see the rest of the processes. And here's the result of the recovery process from a about 505 grams of clean-cut gold fingers. Do you have a guess of how much pure gold this batch yielded? Write it down in the comment section below. thank you for watching my tutorial please comment share and subscribe.