hi everybody in this video i willdemonstrate how to recover the gold plating fromconnector edges aka - "fingers". the fingers are found inmost the fingers are found inmost scrap computers and servers warning the process shown in this videoinvolves highly corrosive acids and should only be done outside orin a fume hood using safety gear such as gloves gogglesand a respirator is mandatory let's begin the fingers are placed in aplastic 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 strainerwith the fingers right at the center now the fingers are covered by the acidand the copper solution and some water to make sure all thefingers 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 greenand doesn't seem like much has happened let's kill the air and see what's goingon nice... we can clearly see some goldfoils floating around seems to be working well cover plate is placed back on and theair tube is connected here we are again forty-eight hours intothe process the solution colors now very dark green in here we can clearly see that someof fingers have been completely dplated
day 6 seems like the majority of thegold plating is now loose let's keep it in the solution one moreday just to make sure now you might ask yourself what exactlyis going on in this process and every common printed circuit boardthere's basically three layers of metal plating copper nickel in gold the point is toslowly etch away the copper and nickel to free thegold layer. to be honest chemically speaking thecopper chloride etching system is quite complex. howeverthere are three simple things
that will push this process forward andare important to remember: first is having free hydrochloric acid second is the presence of copper ionsin the solution and the third is dissolved oxygen.maintaining these three parameters will ensure the aging process willcontinue on the next batch of fingers. here we are in the seventh day it's timeto recover the gold falls from the solution and what's left on the fingers. i'll letthe main solution with the majority of the gold
oils settle for a little while and beginto wash the fingers and collect the coils that are stillhanging on the fingers. the fingers in the strainer are washedwith plain water in a five gallon bucket. this will take awhile you probably get the point just shake until all the gold falls off. let's fast forward we still haven't finished with thefingers, it is now set aside to dry completely will return to that later.
and now for the main better gold foils. aftersettling for a while the bulk of the etching solution isfiltered first by pouring just the solution on top. you could see thefiltrations flow-rate is quite fast. and here's our recovery product nice andshiny gold foils the etching solution is moved to storageand 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 powderare drained
filter. the filter and the foils are placed in aregular open mouth beaker which is placed on top of a hot plate the gold foils and filter are nowcovered with a diluted hydrochloric acid half water in halfacid the plate is turned on to medium heat and the beaker is covered with a watchglass now that the solution is quite hot theaddition of concentrated nitric acid begins. there's about three millilitersof nitric in this pipette.
this is enough to complete the task athand. as the acid is added we can clearly seean immediate reaction. hot aqua regia his so corrosive that aside from dissolving the gold foils itwill also disintegrate the filter paper down to a pulp. by the way remember the fingers we setout to dry? well, once they're dry we can squeeze outa little bit more gold than we got earlier just shake it hard !!!
see that gold...? this goes into the aquaregia solution as well here we can see the gold-bearingsolution and the pulp settled to the bottom ofthe flask. the gold-bearing solution is filtered one last time to get rid of the pulp and any othersolid particles let's flute the filter real quick... and wet it... the pulp and the solution is poured intothe filter
and allowed to drain all the way through. when all of the original gold solutionhas been drained, and the filter and the pulp are washedseveral times until it becomes white again. the gold solution is now ready for therest of the refining steps such as reduction up the gold, washing itand melting it the steps are already covered by myother videos so just click on these boxes below tosee the rest of the processes. and here's the result of the recoveryprocess
from a about 505 grams of clean-cut gold fingers. do you have a guess of how muchpure gold this batch yielded? write it down in the comment section below.thank you for watching my tutorial please comment share and subscribe.
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