first melt newbie problems

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baby_beans

Member
Joined
Jun 19, 2018
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15
I think this a good sign in the melting cup after rather a lot of borax was melted with unknown PGM recovery dust. But I'm completely new to this, is this possibly just copper or tin? Thanks.
 

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A method I'm exploring where electronic waste is converted to mixed hydroxides then rinsed with ammonia leaving hopefully only second row transition metals, then melted, poorly
 
Thanks for all the replies, I tried more heat, pretty happy with the color
 

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Baby,

So many times I thought I would get a better melt than I did. It looks copper, but so does rose-gold.

One thing you can do is re-melt & smelt.

I “scrub” all gold I refine b/c sometimes that is all it needs to cross the point of “worthwhile”.

One technique I use is something bought in your local Home Depot...Spectracide stump remover. It is a potassium nitrate. Some will argue it can contaminate your melt with copper. I have found the opposite. If your melt consists primarily of gold it will “cleanse” it.

It will flame a brilliant white & burn off many lesser metals on the periodic table.

I use it religiously, just in case or to bring a nugget over the bar.

Hope this helps :D

Rachel
 
Thanks Rachel, nice signature also. I read that borax does basically the same thing but I read it on Wikipedia, so who knows if its true. I did burn off a bunch of green and blue flames but I doubt one can hit 100% of the copper
 
You can't refine by fluxing. It can be argued that any concentrating of your target metal is refining but it is a general consensus that a certain percentage should be expected to call it refining. Did you put the button in acid to remove impurities from the surface or clean the button in any way? I don't see how just heating would have made that big of a difference in the color.
 
baby_beans said:
I think this a good sign in the melting cup after rather a lot of borax was melted with unknown PGM recovery dust. But I'm completely new to this, is this possibly just copper or tin? Thanks.
Great pic! Can't tell you what's in the melt from it, but A+ as abstract art.

Seems to me, the very first thing you need to do is to determine what precious metals (if any) are in your PGM recovery dust. This info will help you to decide on a course of action. For example, you can melt gold with a propane torch. Platinum, not so much. Platinum's melting point is greater than 3200 F.

My suggestion is that you read up on the topic of testing with stannous chloride. Creating/buying stannous chloride is pretty straightforward. This forum has a lot of info on the topic. The more challenging bit is that this test requires that you dissolve the precious metals into solution. There are a few different approaches to this, some safer than others. Again, you'll find these approaches described in the forum.

Good luck!
 
Geo said:
You can't refine by fluxing. It can be argued that any concentrating of your target metal is refining but it is a general consensus that a certain percentage should be expected to call it refining.

While I agree with your above statement, you can increase purity of a melt slightly by using a flux. While this is no where nearly as drastic as refining it will raise the bar on your button a small amount of several % points. Multiple smelts will increase purity in much smaller increments than the first.

I melted a button the other day that I had tested by XRF & it came back 94.4%. The contaminating metal was copper. I didn’t feel like dissolving it so I melted it with the below flux & let it “cook” for a little bit. I did this 3x. I had the same button re-tested today via XRF. It came back @ 98.7% Au & less than .2% CU.

The remainder was Pd! That will really teach me to mix up my gold crucible with my palladium one! Must have been a couple Pd beads left over :x

Didn’t improve it to 99.9 but definitely helped out some :D it ended up weighing 11.4 DWT

In my flux I use a combination of:
Sodium Bicarbonate
Anhydrous borax
Silica glass

I let it cook for a while & then at the end I use the Potassium Nitrate
 

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Rachello to be honest I don't recall the last time my gold had that much copper in it at melt.

I prefer to clean the powder thoroughly before melting it. Even from a dirty drop from something like ceramic processors 30 minutes cleaning gives over 99% before even thinking about re-refining it.

That's got to be the quickest easiest option.
 
Yup that was why I added to this thread in gold melts I screwed up. It was a heavy black cake that filled a coffee filter up to about 2 inches. I rinsed & let it dry in the filter. Added alcohol & put heat to it.

After melting I realized there must have been something copper ((maybe a small earring) in the middle of the cake & it contaminated my melt.

I always refine as much as I possibly can while the Au is still a powder. The main reason why I tried to improve it with a flux...I was annoyed I melted it & didn’t feel like starting over again!!

Rachel
 
I reclaim the gold in the first dirty drop and then refine the dropped powder. If I'm not satisfied with the color or texture, I may refine the powder again. It is much easier to dissolve powder than larger solids. HCl and sodium hypochlorite (bleach) will easily dissolve powders and the excess oxidizer (bleach), if there is any, is easily removed by heating and stirring. So very easy to work with powders as opposed to heavier solids that it seems ridiculous not to refine dropped powder a second time. Of coarse this is based on the need for purity.
 
The silica is absorbed by the flux. When smelting or in certain melting processes, silica is added to the flux to help absorb other impurities.
 
Well I finally got a small button, but it's not quite gold colored. Looks more like white gold. Now I don't know how to get rid of the silver color. I think one mistake I made was not putting it into AR solution twice, to re-refine it. I did however add some sulphuric acid so I don't think it has lead. Interesting. :?
 
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