Non-Chemical bar is 5 inches long and half an inch thick

[PreciousMexpert]

if a customer brings you a bar of scrap gold that's 12 K
the bar is 5 inches long and half an inch thick
how can refine that
Do i
1) flatten it with a rolling mill
or
2) melt it and pour it in water to make little balls

 

[lazersteve]

Melt it with an equal mass of silver and slowly pour into a large metal bucket of cold water.

This will form 'cornflakes' which can be reacted with 35% nitric acid (use distilled water to dilute) to remove the silver and base metals.

Let settle and siphon off the liquid then rinse thoroughly.

Recover the silver from the blue-green solution with solid copper.

The gold will remain as a spongy brown powder or honeycombs of brittle brown solids like this:

Process the properly washed gold in AR to refine.



Steve

 

[leavemealone]

I am going to save a moderator some time,because one of them will always tell you to spend some time doing a lot of research and reading here on the forum,everything you need and should know is on here somewhere,you just need to take a couple of days if not weeks and do some research.And you most certainly need to read hoke's book,every single step you need to know is printed in her book.If you don't know the book I am referring to simply let one of us know and we'll make sure you get an E-copy of it.Most of us call it the refiners bible,it is vital you read and comprehend the steps taken.One last thing,anyone on the forum will tell you I am a freak about safety,under NO circumstance should anyone be using or even handling the acids we use on here without a thorough understanding of what these chemicals are capable of,and taking the proper precautions first.Im not trying to be rude,Im just trying to keep you safe.Ok now onto your question.

melt it and pour it in water to make little balls

...Well youre close.Flattening it is not going to solve anything unless you are going to dissolve it in AR and recover the powder,but you don't want to do that with the gold being at 50%.It is a great method for refining,but you should wait until you are at least in the 90% range or higher.
The melt and pour it method is called inquarting.You need to bring the gold down to 6K or 25% gold,by adding silver to what you have.Just weigh the bar and add that weight in silver to the gold and melt it together into one conglomeration.Now you are going to process this with the nitric and you need to increase your surface area as much as possible so the nitric can attack it efficiently.You can "flatten it with a rolling mill" if you have access to that or inquart it.Heres the steps to inquart it.
Take a large stainless pot or other container and fill it to the rim with water(I use a turkey fryer pot).pour it into the water but make sure you are at least a few feet above the water.The distance the gold travels allows it to gain speed before hitting the water,the natural surface tension of the water will cause the gold to flatten out almost like a pancake,we call this corn flaking.One member actually shot a video of them pouring their gold from the top of an A-framed ladder.I will admit it worked great.Anyhow,your ready now to process it with nitric.

Johnny

 

[leavemealone]

Look like steve beat me by a hair,lol.Got a question steve,Anytime I've done this I always end up with powder.Are you and I doing it differently?Also I had another ap solution from those pins drop as gold(not black) again,you ever figure out why?And last I need some more stuff, let me know if you want anything else.
Thanks,
Johnny

 

[4metals]

Steve's method isn't truly inquarting, he adds an equal amount of silver to the scrap so the resultant alloy doesn't totally break up when you leach out the silver. If you are adding 3 to 1 silver the gold breaks up and looks like coffee grinds. Either way works since you'll be refining it further in aqua regia.

 

[lazersteve]

Johnny,

When I performed the inquart reaction I used a slightly lower amount of sterling than I calculated was needed. It's likely this is why I was able to get the results in the photo.

I wish I had taken a snapshot of the cornflakes before I reacted them with nitric as they were unusually golden compared to what I typically see.

More often than not my inquarts produce a spongy gold like this:

I added the red circles to indicate pieces of gold that did not dissolve due to poor mixing of the melt.

PM me and we will work on another trade.

Steve

 

[lazersteve]

Steve's method isn't truly inquarting, he adds an equal amount of silver to the scrap so the resultant alloy doesn't totally break up when you leach out the silver. If you are adding 3 to 1 silver the gold breaks up and looks like coffee grinds. Either way works since you'll be refining it further in aqua regia.

Metals,

The 12kt gold bar is already 50% base metals, by adding 100% of the weight in sterling silver in the melt the result is 6Kt gold alloy, or 3:1.

Here's my math for a 50 gram bar of 12kt gold:

50 x 0.5 = 25 grams of pure gold and 25 grams of base metals plus silver.

50 grams of added sterling + 25 grams of base metals plus Ag in the scrap = 75 grams of inquart.

75 g / 25 g (inquarts mass / gold mass) = 3:1

Did I miss something?

Steve

 

[leavemealone]

if a customer brings you a bar of scrap gold that's 12 K

4metals, Did I miss something?I've only been on the forum a couple of years.Guess its possible Im wrong though I don't think so.

3 to 1 ratio is 25% if the gold starts at 12K and you add an equal amount of silver thats 25%,and thats inquarting.

 

[leavemealone]

LOL....you only beat me by one minute that time.. :mrgreen:

 

[PreciousMexpert]

Hi People
I appreciate your help

 

[4metals]

Steve,

I didn't notice the post said 12 karat, that's not common here in the U.S. I just assumed 14 kt. When fire assaying there are 2 different techniques one using 3:1 silver and one using less silver which is less than 3:1 (I've forgotten the exact ratio because I always use the 3:1 ratio) Anyway, the dore with the lower silver addition doesn't break up on parting but it has to be rolled to get good results. The 3:1 always breaks up.

This however doesn't make up for the fact that 1 missed the 12 kt part.

 

[lazersteve]

Metals,

Typically when I inquart karat scrap, I melt 1 part 10K with 1 part 14Kt to get 12 kt ([10 + 14]/2 = 12kt). This makes the math for inquarting easy. I simply use the same mass of sterling as the mass of 10kt plus the mass of the 14 kt. I know this usually isn't possible in a large scale refinery. It's nice to be able to pick and choose what I refine and when.

An example would be :

25 grams of 10Kt + 25 grams of 14 kt = 50 grams of 12kt.

From my previous post this works out to 50 grams of added sterling for the inquart.

No matter the weight of 12kt you have simply add the same mass of sterling for the proper inquart ratio. Whenever possible I like to keep my calculations as simple as possible to cut down on errors.

P.S. I love your posts on building a refinery and fume hood. I'm getting ready to build a 18' x 20' building out back and follow some of your leads. Thank you for your great posts!

Steve

 

[Oz]

I look forward to seeing that Steve. You are very good about doing your research and thinking things through before implementation so I would enjoy seeing your plan come together.

 

[4metals]

Here is an Excel spreadsheet I wrote to run large lots of karat gold inquarted with silver (mostly sterling) In larger shops all lots are melted into bars and assayed for settlement. This sheet allows you to enter bar assays for gold and silver into the gold bar section and silver bars and assays into the silver section. Usually they just enter the gold bars as they accumulate and when they want to process it they log in silver bar assays until they get enough. The program tells you when to stop. This sheet has an upper limit of 5000 oz because that's the upper end capacity of the furnace to inquart the bars into. That can be lowered to a more reasonable number by changing the melter capacity number. The sheet is not protected so be careful not to delete cells with formulas. Also if you put in the weights and assays of the recovered metals it will calculate accountability.
Enjoy !

 

[goldnugget77]

Hi 4metals
that is a neat program