re-refining button

[peaksilver2012]

Hi guys. Just another noob question. I melted my first button (yay!) but methinks I need to re-refine it, as I left out some steps in washing the powder. I want to add some new au to it as well. Can I just dissolve the button in Hcl and Clorox to get AuCl and precipitate with SMB or am I missing something?

Thanks as always,

Preston

 

[leavemealone]

Hi preston.You have a couple of options available,depending on your arsenal of chemicals.You can redissolve it in AC or AR.My personal choice would be AC.In both cases you need to hammer out the button as flat as you can possibly get it.Make sure you use a thick piece of stainless or very clean steel to hammer it out on.Don't try this on conrete,the gold is soft enough to "absorb" some sand particals that break off of the concrete causing a little trouble down the road.The reason for flattening out the gold is to increase the surface to mass ratio allowing the AR,or chlorine to be able to reach a larger percentage of the surface,if you try to dissolve it in button form,it can take a very long time,depending on the size of it.Once you have flattened it as much as possible,simply cut into small strips and add them to your solution.If you use AC(recommended by me),once digested fully,simply evaporate the bleach off just like you would normally,and drop with SMB.If you use AR,you will of course need to neutralize the nitrates first,then drop the gold as normal.
Johnny

 

[Harold_V]

An alternate to Johnnie's excellent suggestion is to melt the gold, then pour it in deep water. Don't use a plastic bucket, as the molten gold has the ability to hit bottom. Pour a thin stream and move around over the water to minimize the chance.

By pouring from the lip of a melting dish, you will create "cornflakes", not shot. That will provide the desired larger surface area.

Don't shortcut washing procedures. I ran enough gold to know that it is as important as any of the other steps if you want a good end product.

Harold

 

[firewalker]

Congradulations, how about some pictures?

 

[peaksilver2012]

Thanks for the replies. I'll decide which method to use today-flatten or corn flakes. I'll probably try the flakes first as I don't have a suitable stainless "anvil" to work on, although I will be adding that to my list of gotta haves. As for pics firewalker, I will most def post some of this next melt. This is a blast learning this stuff!!

Preston

 

[Clneal2003]

Hi preston.You have a couple of options available,depending on your arsenal of chemicals.You can redissolve it in AC or AR.My personal choice would be AC.In both cases you need to hammer out the button as flat as you can possibly get it.Make sure you use a thick piece of stainless or very clean steel to hammer it out on.Don't try this on conrete,the gold is soft enough to "absorb" some sand particals that break off of the concrete causing a little trouble down the road.The reason for flattening out the gold is to increase the surface to mass ratio allowing the AR,or chlorine to be able to reach a larger percentage of the surface,if you try to dissolve it in button form,it can take a very long time,depending on the size of it.Once you have flattened it as much as possible,simply cut into small strips and add them to your solution.If you use AC(recommended by me),once digested fully,simply evaporate the bleach off just like you would normally,and drop with SMB.If you use AR,you will of course need to neutralize the nitrates first,then drop the gold as normal.
Johnny

SIDENOTE: It took me two days in hcl CL to dissolve a 6 gram button of 10k.

 

[Geo]

The hcl/Cl dissolution works best on powders and foils but not so well on larger solids. As far as flattening gold with a hammer, from wiki : Gold is the most malleable of all metals; a single gram can be beaten into a sheet of 1 square meter, or an ounce into 300 square feet. Gold leaf can be beaten thin enough to become transparent. The transmitted light appears greenish blue, because gold strongly reflects yellow and red.[21] Such semi-transparent sheets also strongly reflect infrared light, making them useful as infrared (radiant heat) shields in visors of heat-resistant suits, and in sun-visors for spacesuits.

I would recommend that you study the AR (aqua regia) process. You have half of the formula already, hcl, all you need is a decent nitrate and some heat.