Metal Refining & Recovery, Episode 24: Re-Refining Gold Using Bromine

[Music] that everyone welcome at Kody's lab so I have here about 60 grams of gold foil that I made from my gold bar which I produced in another video from some scrap gold jewelry I bought on eBay now a lot of people when they saw that gold bar especially when they saw how the foil acts they deduce that it contained a small amount of copper contamination this is most likely due to the fact that I processed the gold very quickly now I was in a hurry and I must have brought down a lot of copper in the precipitation process fortunately I now have this x-ray gun here like actually x-ray it and see exactly how pure I was able to get it okay so I'll do a quick alloy test there it says in on this we can see alright so there we are we do indeed have about two and a half percent copper and going down it's about 95 around 96 percent gold so yeah it's about 23 carats yeah I certainly could have done a lot better tiny bit of palladium it's not terrible though for a first pass anyway you might notice that the gold is showing up under W for tungsten that is just a software thing that's not actually a hardware issue under this mode Gold just shows up as tungsten because that's the closest the software can read the peak as is not the gold isn't one of the elements that has loaded for this mode here I'll probably do a video on that at some point so anyway we have 23 carats gold and I'd like to get this up to 24 carats or at least as close to pure as I can so let's redefine it so in order to separate the metals I must first dissolve the gold into solution so that I can separate the metals normally this is done with a mixture of nitric acid and hydrochloric acid otherwise known as aqua Riga and what's that's what I've normally done in the past but there are a lot of problems with it and so I wanted to try another method and that is using the halides elemental chlorine has the oxidizing agent so that's the total amount of golds is 1.7 moles I am going to do this in batches so we will reduce that number I don't want to do all my gold all at once on untested process so this is the equation for the dissolution elemental chlorine elemental gold little hydrochloric acid and absolves it makes they are on chloric acid now i think i was talking to some patreon x' and we decided that it might actually be better to use bromine instead of chlorine so just for me replace the CL with BR and equation should be the same I'm just going to make the chlorine using a calcium high perchlorate we may actually use calcium hypochlorite or to produce the bromine yes there we go I weighed out 205 grams so this is two moles of sodium bromide this won't make enough bromine to dissolve all of my gold so it will certainly dissolve this and probably the next batch as well so there's a sodium bromide I'm gonna add enough water to this to get it to dissolve so now that the sodium bromide is mostly dissolved and I've got a better light going it's at in 60 milliliters of sulfuric acid slowly so it's not heat up the solution too much and this will form sodium sulfate which some more precipitate not all I'm cooling it off will further precipitate the sodium sulfate and drive the reaction forming hydrobromic acid in solution well I'm waiting for that to cool I may as well cut this gold into little pieces that are small enough to fit down neck of a reaction flask a lot of the sodium sulfate has precipitated out now that it's cooled this leaves us hydrobromic acid in solution of course it's very crude so I'm going to first filter it and then distill the acid to get pure hydrobromic acid okay so here we are I've got to set up for a simple distillation a fractional distillation column would achieve a higher purity but I'm okay if I'm getting a dilute acid I just want to get an acid that doesn't have all the sodium and stuff in it okay looks like it's done and I've got some hydrobromic acid my leftover sodium sulfate this is the place we're going to be using except we're replacing this with hydrobromic acid and it'll produce bromine instead of Forney so I've weighed out a hundred grams of calcium at the quarry theoretically I only need about 70 grams but it's very amazing in excess so I make sure I authorize all theoretically any oxidizer could be used now strong oxidizers the hydrogen peroxide I tried it it kind of work but it really like the froth up I'm just gonna use this well that's a reattach all of my distillation equipment and they're dropping photo up on top here that's why I'm gonna hydrobromic acid should get bromine that's going over okay I'm just about ready distillation apparatus is setup you got a bottle the phrasing milk in the cooling water keep it full got a scrubber with some sodium hydroxide here to get the bromine vapors but of course also doing this in a fume hood so anything that doesn't catch will just get stuck right outside here we go add in the hydrobromic acid to the calcium high perchlorate we should see bromine forming this who's gonna add it very slowly I'll probably end up with a bunch of liquid bromine in this chamber over here but I do have it set up in this distillation pot so I can keep this up and drive it over if it doesn't produce enough Heat okay there's a bromine so you'll probably catch it on the time-lapse cuz it was going but I was thinking that maybe the calcium chloride hi perchlorate was being used up because the bromine stopped coming over even though liquid was going in and so I decided to open this up and put a little bit more calcium core I didn't ever chloride in there contested and turns out I was right a bunch of that bromine vapor came out at me but fortunately you had just took care of it no problem that's what this thing is for those occasional accidents I want to try to avoid releasing gases as much as possible but occasionally when something like that happens it's nice to not have it go out into the room so all of its all of the acid is in I've got the heating mantle on [Music] bro means still coming over it looks like quite a bit I think I'm gonna get a pretty good yield out of this obviously not a hundred percent but bromine in my little Nile red what let's use it just results in gold so I'm putting in the gold now I have 65 grams of gold here and I'm just gonna put all of the bromine in now we have an excess and he left over bromine I can just foil back out that's what's nice about the halides is you don't have to evaporate it dry just simply raising the temperature will drive the growth the halide off badass stir bar it's really gonna hurt now I'm gonna add some uric acid or hydrochloric I'm just gonna add enough to cover the gold but should be in excess and now for the bromine can't really see what's going on not bubbling or flossing or anything it shouldn't make any gas another bonus of this process let's pick this up so you see what it looks like from underneath now you can see liquid bromine in there sitting down on the gold okay presumably the Gold's in there being dissolved it's currently almost 2 a.m. no let us go overnight I've got the stirring turned on I don't think the stir bar is actually moving but I'll come back in the morning and see if everything's liquid so I was still up and I decided to come check on this before I actually went to bed so it's been just over an hour and I noticed something it's actually stirring a little vortex in there you know what that means to me this gold has been dissolved to the point that the stir bar works here I want to actually look it and see what that gold looks like right now okay so I taken the flask out so we can look at it and the first thing I notice is that it's rather warm it's not quite hot enough to boil the bromine but it's it's heated up a little bit and I don't have the heating mantle on so that's all heat just from the dissolving gold so I guess dissolving a larger quantity might be a problem so that's good that I started with a small batch but look at this like some just shredded pieces of gold left it's almost completely gone that is crazy that dissolved it faster than the nitric acid would I mean it does help that it was in a tin foil but even still [Music] that's remarkably fast I was not expecting that right well I need to go sleep so here we are after I've taken a long nap the gold is completely dissolved let's turn on the heating mantle and let's drive off the rest of the bromine we should collect the excess down in that bulb there there it goes the bromine is leaving with that's gone I'll be able to drop the gold out of solution let's see what the nitric acid I'd have to evaporate it down and tell it's a syrup add more hydrochloric acid and do that again and again just to get rid of all the acid this is so much better here we are the extra bromine is right here let's take this let's go run this through a filter likes long later on it and it's rinsing this gold through the filter we are all the insolubles are now captured and what we got in the liquid is probably mostly gold and copper chlorides the next task is to do that probably about five more times and just like that all the gold has been dissolved this flask here Taine's around 1,300 milliliters of solution which is probably worth over $10 a milliliter isn't that crazy we're in the homestretch now though let's get this converted into metal then against generator beaker that will make sulphur dioxide by dropping hydrochloric acid on to that advice Little Feat a glass tube here to put the gas into the solution and this will reduce the gold - metallic pan so hopefully it will not reduce the copper to the bottom that's added in the sulphur dioxide we go go through a little bit of time and some point we should see metallic gold poorly here we are you see I've added a bunch of the gas well you can see there is a bunch of gold powder settling out of the solution so I've got a long ways to go though now the goal has been successfully converted back into metallic form I've washed it with some pure water right now I'm putting it onto a little pan so they can dry it out so here's the gold powder after being dried one interesting thing about this is it still feels heavy even though I've removed the water weight which I guess makes sense because gold is very dense get this onto this paper here let's do it some of the time transfer it into this crucible so I can melt it down the sand and the floor and everything's gonna be a valuable Gold Award by the time I'm done isn't it probably do a video at some point about recovering the gold from the floor like Christmas this paper here put that with my other gold containing paper and gloves speaking of which this cylinder in the back here is where I put all the wash water and the solution that didn't drop out so it's got copper but presumably a small amount of gold actually it's probably quite a bit of gold so I just put in some zinc zinc powder and that'll help but a precipitate the rest of the gold let's melt this down Ernest is up to temperature and align it torch you got the mold this way the goals will lay flat and not solidify instantly make a nice rectangular bar gold we think this is a torch a little bit glowing some of that dirt and fell on it oh there it is nice little bar of gold it looks a lot better now don't it maybe the size of the crystals in the front that is an indicator of purity I think yeah there's some crud that fell onto it I think from the inside of the furnace you know off the lid I tried to blow most of it off with the torch but you know it's still there I can probably get a little bit of sandpaper though and I'm not sure if I want a sandpaper it looks pretty as is right well let's go x-ray it and see how pure it is okay time for the moment of truth sit this with the x-ray okay you saw the whole process that's just a quick alloy chick and you see 98 2.88 so still not four nines or anything but certainly a lot pure tiny bit of cadmium lead bismuth lady um yeah I still didn't get the plating up there's no copper that's definitely important now I hope he is not red in this color is just for fun let's also kick one of these commercially made gold bars which should be at least three nines fine so so down there let's check it okay and it is done bring this down and yeah is telling me that it's a hundred percent pure yeah which makes sense now for the question I'm sure a lot of you are asking how much does gold bar way so a scale 304 grams so just under 10 troy ounces now obviously that is a bit lighter than the eleven troy ounce bar that i started with a lot of that of course is copper and also since I was going for purity I didn't recover all of the gold in one step you know there's still quite a bit that was left over which I cemented out with the zinc which I'm currently recovering probably get quite a bit of gold out of that but of course I'll have to refine it to get to this purity but at any rate this is pure enough now I think I feel okay flattening it out once again and adding it to my AG gold foil ball but I'll probably do that in another video or something so now I'll leave you guys with the spreadsheet showing the amount that I spent and theoretically could make by selling the gold now adjusted for the fact that it was 95% pure hope you enjoyed I'll see you next time [Music]

Channel: Cody'sLab

Views: 541,908

Rating: 4.9541864 out of 5

Keywords: Gold, chlorine, copper, refining, melt, distill, bromine, element

Id: a_EdGQyHTxU

Length: 21min 32sec (1292 seconds)

Published: Thu May 17 2018

Reddit Comments

[u/Venexion]

Cody should just send his gold to be processed by Nile Red. Nile has a better lab so I feel like he could get better results