First time inquarting Karat gold

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resabed01

resabed01

Well-known member
Joined
Sep 6, 2009
Messages
467
Location
Alberta
Hopefully I did the math right. I had;
23.68g of 10K = 9.86g 24K Au (assumed)
17.68g of 14K = 10.31g 24K Au (assumed)
10.22g of unknown karat, I assumed it was at least 14K = 5.96g 24K Au

So, estimated total 24K Au is 26.134 x 4 = 104.53g of 6K karat inquarted

104.53g - 51.58g karat gold = 52.95g of sterling to add

The karat gold without hallmarks I tested with 50/50 nitric and as far as I can tell it was real. There were a few plated items that the nitric brought to my attention that were pulled from the pile.

I added 52.53g of sterling, melted and cornflaked. I know, a bit off. I came out with 103.3g of 6K

Now correct me if I'm wrong... I need 2.55ml of 50/50 nitric for each gram of 6K gold?

That would be 263.5ml total.

Now, I inquarted with sterling not 999 silver, will that make a big difference in the nitric needed?

Or maybe I'm overthinking this all and should just get on with it :lol:


 
depending on your accessibility of nitric, its better to err on too much silver. add a little more than you think you will need just to be sure.
 
Here is a work sheet that i created that may help you.
 

Attachments

  • karat gold worksheet.pdf
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Your welcome Butcher. It's actually part of a handout i have that goes with the lesson plans i've created. I've been trying to teach refining from hoke using it as a lesson plan for clients. I've found that it is easier to learn from Hoke than it is to teach from it if that makes sense. I've laid my lesson plans out more in a educational curriculum that matches today's traditional teaching techniques. Not that Hoke isn't right, but it just don't seem to flow from the book quiet the way i like it. This is actually part of a series of educational courses designed to teach you the fundamentals of refining hands on first, with educational fundamentals that you can build on making Hoke the Bachelors of science to your Associates degree. By the time i'm finished it will include educational principles set out in a course curriculum like an institution of higher learning would have. Whole lot of work! This is actually the forerunner to bigger and better things. :mrgreen:
 
Palladium, where your worksheet doesn't match my calculations is on the amount of nitric to use. I read on here where a member stated to use 2.55ml of diluted (50/50) nitric for each gram of 6K gold, not base metals. I remember because I wrote it down. On your worksheet it states I'll need 2.5ml of 70% nitric for each gram of BASE metal. Then to dilute it with a equal part of water. So in my case with my amount of gold and base metals I'll need a total of 392ml of diluted nitric, correct?
I've added 260ml of diluted nitric so far. How does one tell the nitric has finished it's job? Will all bubbling cease? According to your work sheet I'm still ~130ml short of finishing the digestion of base metals, which in my case is mostly sterling. The solution is a very deep blue which tells me a lot of copper is present. I suppose copper upsets the amount of nitric needed.

I read about this in Hoke's book about placing the vessel in a tray of water and covering it to keep fumes down. I thought I'd try it.

 
That is correct. You will need 196 ml of nitric and 196 ml of water. Once the reaction stalls add heat to the beaker to get the reaction to finish to completion. You will notice it is complete when you add some nitric and no longer see red from the fumes. It's not all that important in this step to not over shoot the nitric. With the calculations you did their might be a little free nitric left but it better to error on the side of to much as it is to little at this point. You don't want any silver left that may carry over and make chlorides. Once your done with this step you can draw the nitric off and cement your silver with copper for use later on.
 
Palladium have you got to the part of your
Curriculum where you devise a final or maybe
A midterm :p
Maybe we could have some kind of contest for
Say the high score or such
I like tests
:lol:
Thanks steyr223 rob
 
Well, I let it sit overnight and today I poured off the copper and silver nitrate solution and added 50ml of fresh 50/50 nitric acid. Barely any reaction. I added heat for a while and it pretty much stopped reacting.
I'm going to say it's done leaching the base metals. On to rinses and AR.
 
Mash it somewhat with a stir rod. If it feels spongy and collapses, it is likely finished. If you can still feel hard chunks, it isn't finished
 
resabed01 said:
The solution is a very deep blue which tells me a lot of copper is present. I suppose copper upsets the amount of nitric needed.
Click to expand...

If i'm not mistaken it takes 1.2 ml of 70% nitric to dissolve a gram of pure silver. By comparison it takes 4.3 ml of 70% nitric to dissolve 1 gram of copper.
 
I took your advice GSP and mashed up the chunks, they were all pretty soft. Couldn't find and hard pieces.
 
Use distilled water for your rinses and add it to your nitrate solution for cementing. If you use chlorinated water you will create chlorides and when you add it to the nitrate solution it will create more. A little bit can be dealt with, but i try and avoid it as much as possible.
 
Palladium said:
Use distilled water for your rinses and add it to your nitrate solution for cementing. If you use chlorinated water you will create chlorides and when you add it to the nitrate solution it will create more. A little bit can be dealt with, but i try and avoid it as much as possible.
Click to expand...


Yes, I used distilled water for the rinses.... 3 of them then twice in boiling hot water. The last wash the water came out clear. I'm trying to dry it so I can get a weight before moving on to AR.

 
So I was away from home for a week with work. When I returned home I weighed the dried power and had 22.5g, about 3.5g less than anticipated.
Using the actual weight I calculated on the worksheet that I'll need 22.5ml of nitric and 85.5ml of Hcl... great, my 70% nitric is already cut 50% with water so I figure 45ml for that.

I measure out the Hcl I need and add 30ml of 50/50 nitric not wanting to over do it. At first there was barely a reaction but after a while things started rolling once the solution self heated.
This was my first time using AR so I wasn't sure what to expect. After a bit I realized I was losing values because the beaker I was using wasn't covered. By this time to was boiling on it's own pretty good.
A watch glass fixed that. While this was going on, a neighbor came over and we were chatting for about an hour maybe.
After she left I went to check on the AR and it was done?? The solution was a deep orange with some dark powder on the bottom. I thought maybe it ran out of nitric and stopped because up to that point, I've only added 30ml.
I add another 6ml of nitric with a pipette and nothing happens....ok, it really is done and the small amount of black powder in the bottom must be PGMs.
Now I've got excess nitric which was surprising because according to the worksheet I shouldn't be at this point yet.

I take my small BBs of gold I've made from e-scrap and added them one at a time to consume the excess nitric, pounding them flat first to increase their surface area. The solution gobbled them up no problem, that was a additional 2.5g of gold I added. I don't want to add my 6.3g button

So, to denoxx I need to evaporate this down to a syrup and then re-hydrate with Hcl, correct? How much Hcl should I be adding? Enough to make the solution acidic for the SMB?
 
One comment when using AR and the reaction stops but you have undissolved material always add a little hydrochloric first and then a little more nitric if nothing happens, try adding a little hydrochloric to your solution and see if the reaction continues.
 
I didn't mention it but I tried adding a bit more Hcl to see if it would kick the reaction again.... nothing happened.
Today I put the beaker on low heat to evaporate it down to rid the excess nitric acid. I started with about 150ml of solution and it took all day to go down to about 25ml.
I also see that those PGM powders I had on the bottom of the beaker are now dissolved. The liquor is completely transparent
I was also watching the temperature, it kept at a steady 60 deg C until a point where I noticed it stopped steaming. That's when the temperature started to climb to 90C.
I took it off the heat. When the beaker cooled it crystallized and solidified into a dark orange lump. Is it safe to say the nitric is now gone and I can re-dissolve the auric chloride
crystals with Hcl then move onto SMB?
 

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