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J

JHS

Well-known member
Joined
Jan 28, 2013
Messages
398
I had a solution that was holding some k gold.There was a mix up in chemicals by the supplier and I had no idea what he sent me.After trying to drop the silver with copper and gold with smb,and having no reaction on either,I dropped everything with aluminum.
Now I want to melt it and pour it into a cone mold,but I don't have one big enough to handle all the material.This is what I am planning.
My spruce and drag are not big enough,so I will make a wooden one.
Then cut a funnel and make a open sand casting with it.I have plenty of sand casting sand,and plenty of talc.Let it dry for several days and hope I can turn it over.Since I will need to pour a couple of 100 oz.pours I am in hopes I can put a s hook in the top and remove the cone and use the casting again.
Question,should I dust the casting again with more talc before the first pour?
Question,should I use just borax as a flux.
The material contains gold,silver,copper and aluminum.
All this is to just get the aluminum and most of the copper out of the powders.
Please if you have a better idea, I'm all ears.
thanks john
 
JHS said:
I had a solution that was holding some k gold.There was a mix up in chemicals by the supplier and I had no idea what he sent me.After trying to drop the silver with copper and gold with smb,and having no reaction on either,I dropped everything with aluminum.
Click to expand...
If you have dissolved gold and silver then all the silver stays in the sediments as silver chloride while the gold goes into solution.

If I understand you right you tried to cement silver with copper without getting a reaction. What you should have gotten here was any gold and pgm:s cementing out.

If you then tried to drop gold with SMB it should already have cemented on the copper, or if there were any nitric acids left in the solution the copper should have been attacked by the acid.

From your description it doesn't sound like your solution contained silver or gold. Did you test it with stannous before starting to do your procedures?
How do you know that you have any gold at all in the material?
How much material do you have and how much gold do you expect to get from it?

Göran
 
I have to believe that the powder i got on ebay was not sodium nitrate since I had to add a lot of 68% nitric to get it dissolved.
I also tried to make nitric with this supposed 98% sodium nitrate,with no success .All my tests were positive.After I dropped with aluminum the test results were negative.As to the amount of gold,well it's a lot of 18k that was inquarted with .999 silver.
I do know where the gold is,I was just asking if anyone could see any flaws in my pouring process.
I am going to follow Frank's advice and put it into some hcl first.It makes seance to me.
thanks john
P.S. Test solution is cheep to make and simple to use,I use it at every stage on every process.I use a lot.
 
JHS said:
I have to believe that the powder i got on ebay was not sodium nitrate since I had to add a lot of 68% nitric to get it dissolved.
I also tried to make nitric with this supposed 98% sodium nitrate,with no success .All my tests were positive.After I dropped with aluminum the test results were negative.As to the amount of gold,well it's a lot of 18k that was inquarted with .999 silver.
I do know where the gold is,I was just asking if anyone could see any flaws in my pouring process.
I am going to follow Frank's advice and put it into some hcl first.It makes seance to me.
thanks john
P.S. Test solution is cheep to make and simple to use,I use it at every stage on every process.I use a lot.
Click to expand...
The fact that you could not get a metallic return using copper as a sacrificial element but got a return with aluminium set's off alarm bells, so may be you should start at your testing of the eighteen karat alloy
If you inquarted your material should not your Ag and Au have been separated at that point in just plain Nitric acid?
I have not heard of nitrate salt's used to digest Ag alloys as it need's to be used with hydrochloric acid and then is only really used for Au.
May be you would like to describe your initial digestion of your Ag/Au alloy and then how you digested the remaining sediment .
Then explain your rout to cementation and precipitation.
And as to using a sand mold instead of a proper cone mold I would think it would be less effectives, you can not preheat a sand mold in the same way and that is important so as to give metal time to drop to the bottom.
 
justinhcase said:
And as to using a sand mold instead of a proper cone mold I would think it would be less effectives, you can not preheat a sand mold in the same way and that is important so as to give metal time to drop to the bottom.
Click to expand...

Although I have never used a sand (cone) mold I would agree with Justin here - I "think" (don't know for sure) that your slag (which comes of "first" in the pour) is going to start to solidify before the pour is done so you are not going to get compete/proper separation (metal to the bottom - slag to the top) --- the mold needs to be "hot" so the pour stays fluid long enough for the separation to take place

As far as your flux 50/50 borax/soda ash --- the soda ash will help make the flux/slag more fluid - fluid is "important" for the metal to "flow through" the slag & prevent small balls of metal hanging up in the slag - borax alone is a very heavy/thick slag/flux --- you may even want to add some fluorspar to make the slag/flux even more fluid

Kurt
 
Justin,
I am by no means a chemist.When I purchase chemicals,I must rely on the seller sending what was ordered.When I made up the poor mans ar,and it did not react,I should have dumped it.But I didn't, I added 68% nitric and the reaction carried forward to completion,except I saw no silver.There was almost nothing in the reaction flask.I added some copper turnings to the flask and they turned snow white with no other reaction.I then tripled the solution with distilled water added 20 oz. of smb after filtering again.The smb foamed white as snow,almost over the top of the flask.
As I stated earlier I am not a chemist,and could not explain this reaction even if I had another 50 years.
I can tell you that this afternoon I melted a few grams,and the gold is in the melt.I did put the powder in hcl last night.
Now I am wondering if I should just run the powder back through a new batch of ar after a second bath in hcl.

Kirt and Justin,thanks for the advice against the sand casting.Tomorrow I will start building a proper steel cone mold.
thanks john
 
JHS said:
Justin,
I am by no means a chemist.When I purchase chemicals,I must rely on the seller sending what was ordered.When I made up the poor mans ar,and it did not react,I should have dumped it.But I didn't, I added 68% nitric and the reaction carried forward to completion,except I saw no silver.There was almost nothing in the reaction flask.I added some copper turnings to the flask and they turned snow white with no other reaction.I then tripled the solution with distilled water added 20 oz. of smb after filtering again.The smb foamed white as snow,almost over the top of the flask.
As I stated earlier I am not a chemist,and could not explain this reaction even if I had another 50 years.
I can tell you that this afternoon I melted a few grams,and the gold is in the melt.I did put the powder in hcl last night.
Now I am wondering if I should just run the powder back through a new batch of ar after a second bath in hcl.

Kirt and Justin,thanks for the advice against the sand casting.Tomorrow I will start building a proper steel cone mold.
thanks john
Click to expand...
Being constructive and braking your situation down into small digestible chunks is important.
Personally I would not progress to hot work until I had run through and understood exactly what is happening at each step.
It will not take you any where near 50 years but if you what good result's it is what you will have to do.
You made an alloy of 25% Au then went to digestion,Now i can not see any separation form your digestion of the silver and progressing to A.R.
The more Ag you can digest out of your initial alloy the easier you will process the Au.
If you tried to go straight to A.R. you will have a load of undigested silver chloride coating all your alloy and not very much will go into solution.
You would have to wash in ammonia and start again once you have reread all the available information on the subject.
 
justinhcase said:
If you tried to go straight to A.R. you will have a load of undigested silver chlorine coating all your alloy and not very much will go into solution.
.
Click to expand...

I believe you meant to say silver chloride (not chlorine)

Kurt
 

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