gold filled,tin and silver chloride

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wood4lif

Active member
Joined
Apr 7, 2012
Messages
43
when recovering gold from gold filled items my solution has so much white precipitant with the green solution that im almost sure its a combination of tin and silver. i take a small sample out to test with ammonium and it turns colbolt blue and yet il take foils seperate from thr powders, boil the white residue off, or should i say i attempt to the best i can,. when i melt the foils(5-7) grams its silver in color all the way through.. it can be silver.that should have dissolved with the nitric. is this tin thats causesing me all the head aches and what is the best way to deal with this before and after its been alloyed with the gold?
im sure the best advice is to avoid this before it gets to this point. but i coiuld use some advice before and after. thank you
 
Sounds like the whitish powder is copper I chloride which is soluble in HCl.

What steps did you follow to get to this point?

Steve
 
i put approx 200 grams of GF in a 50/50/ nitric solution untill all that is going to disolve has disolved.
the out come at this stage is always different. somtimes il have a dark green solution with a yellow precipitant and foils. other times a milky blue solution with foils, a solid thick rust solution, a light clear blue with white and purple precipitant.
its seems like i get my cleanest disolution when my base metal is copper, but that also takes the longest and uses the most acid.maybe you can help me describe what im seeing hear with these different reactions.
i used 50/50 nitric on them all and i also incinerated prior to disolution. i also seperate the iron base metals from the rest and i dont mix any copper base metals.
 
well i guess my post displayed to much ignorance. heck, maybe even stupidity in some of your eyes,
but if there is anyone who can or will answer these simple questions id appreciate it. you can even ask me a question about structural concrete and i promise i wont ignore the question no matter how foolish it may sound in the mind of another journeyman cement mason
 
wood4lif,

I will try and answer the best I can, other could give you a better answer.

base metals come in many combinations of metals, they will react differently to acids, some will give distinctive colors to solutions, some do not color a solution at all, some metals like iron can give several colors to solutions depending on concentration what acid or base, pH of solution, temperature and so on, I have seen iron as clear yellow, green orange brown and red, so you see we cannot judge what is in solution by color, as it would fool us, although colors of solution can be an indication of what is in solution, we can test solutions for most any of the metals, with many of the base metals it can be a difficult test, as sometimes we need to remove the metals in a series of tests to determine a certain metal in solution, some tests are more easier and can be used to test for a metal with other metals in solution, some tests we use to determine if our solution contains values and if so what metal is involved, the metals are cations (testing for cations), anions would be the salts of the acids we used like chloride, sulfate, nitrate, there are also tests for these anions.

Plated or gold fill can have many different types of base metals, with costume jewelry you could have any metal involved lead, zinc, bismuth, tin, copper, aluminum, you name it, if they can melt it into an object they probably make jewelry out of it.

I do not know if this helps to answer what you’re looking for but I tried.

No it was not a stupid question, just one that cannot be answered easily, how would I know what your seeing with different colored solutions, I am not there to test it.

Have you been studying Hokes, and doing her experiments, this will give you a clue of how several of these metals react in solution, she also teaches some tests to tell if some of the more important metals are in solution, and for like iron that can look like gold in solution how to test for it to tell if the solution is gold or iron.

Do not get upset if someone does not respond to your post in the time you think they should, many times we read a post and figure someone else can give you a better answer than I could, also the forum has grown so much we cannot always read everything everybody posts, there are subjects I have not got to for months, and people who I enjoy helping that I may not read their post until months after they posted, we are even missing birthdays of some of our good friends until they are older and forgot about their birthday, it is that we do not wish them a happy birthday, we did not know they had it, there is no such thing as a stupid question if someone is working to learn the answer, but not all questions have simple answers, but anyone wanting an answer to a question will find that answer if they keep working to find it, sometimes it may not be the answer we are looking for, and any one searching for an answer is not displaying ignorance.

Chill out, if someone does not give you an answer search for it, seek and ye shall find.

Relax enjoy the forum and the enormous amount of information provided here, you will learn that answer sometimes come slowly to the questions and learning can take time,but if you do not get impatient the answer will reveal itself. as long as you do not give up looking.
 
thank you butcher, you seem to be a very wise man and your answer was well taken for it was usefull in many more ways then just refining gold.
also i might add that i wasnt mad or upset, just always eager to know everything about somthing i have a liking or interest in. and yes i read and read and read. sometimes i spend so much time searching that i run out of time to read into what i was searching for, diligence and patience can be two opposites that work good together. thanks again
 
sometimes I search so hard for a question, I forget what my question was, luckily I find answers to many other things, so my search is never in vain. :lol:
 
butcher said:
sometimes I search so hard for a question, I forget what my question was, luckily I find answers to many other things, so my search is never in vain. :lol:
Click to expand...

:lol: :lol: :lol: I can sure relate to that one butcher

Kurt
 
wood4lif - As butcher pointed out - when it comes to gold filled the base metals can be almost anything & everything & you can almost count on tin being in the mix ether as part of the base metal alloy make up &/or the soft solder in solder joints --- so when using nitric to dissolve the base metals you are most likely going to end up with stannic tin (or tin paste as Hokes discribes in her book) This is most likely the white precip you are asking about.

The silver in gold filled is alloyed with the gold being as how gold filled is a karat gold & is there for tied up in the gold & wont come out in the nitric treatment used to remove the base metals --- the silver will come out - as silver chloride in the AR treatment of the recovered gold foils

Concerning the stannic tin - you need to filter/wash your gold foils after the nitric treatment - then dry - then incinerate your foils - when you incinerate your foils - it will convert the stanic tin to tin oxide - then you treat the foils with a warm/hot HCL treatment which will remove the tin oxide --- it may take several times of HCL/filter/wash/HCL to get out all the stannic tin - do it till you no longer get a color change in you HCL.

Concerning the incineration of your foils go to the "chemical processes" part of the forum - look for a thead titled "Metastanic Acid Experiment" --- I posted a reply there - along with pictures that explains the incineration process for removing stannic tin from foils.

After you have done the above your foils will be ready for AR treatment

Also - as butcher asked - have you read Hokes book - she discusses working with gold filled in detail

Kurt
 
thanks for your reply kurt. yes ive read hokes book and still go back to it often for answers. sometimes its takes a second explaination from another source for me to fully absorb what is being explained.
i watched the video steve put out and it makes no mention of the problems tin will give in this process,although its a great video but lacking a crucial part, dealing with tin.......i just want to add that i can understand the reason why all the information for a sucessfull given process isnt given.( for that i found this to be common) but for the student trying to suceed it can be a bit frustraighting. i find that only with great dilligence and further study along with additional help from members like your self, the answer will be found
 
the first time i tried putting together a poor mans AR following the given instructions, after complete failure i learn from another member the additon of sulfuric acid is needed ( another key part left out)..but even so i found that the poor mans AR is a disapointing formula to use trying to refinine gold efficiently
 
wood4lif,
I think studying is a very important part to learning this art, there is so much to it, but you also need working expierience, to really understand it, it can be hard to explain every detail in a process, some things you do while processing or observe that you may not think of while trying to explain a process, not everybody will process a certain material using the exact same steps, but both can come to similar results in the end.
 
Wood4lif as Butcher and the others are trying to point out this subject is huge and I doubt anyone knows it all, I know I don't. There is so much to learn and so many different approaches to reach the same conclusion. Reading and studying are an important part of the learning curve to help prepare you for the actual hands on recoveries and refining and when trying to learn there is almost certainly an overload of information that only actual trials and experiments help to clarify but they raise further questions along the way. Be patient you will get there and look back at this as a good education.
As a way of pointing out the overload point you stated that to make poor mans AR work you need to add sulphuric, forgive me but I think that's wrong, when you add a nitrate to hydrochloric you give the solution the oxidiser it needs, the same as adding bleach, to dissolve your gold. I think you may be confusing the making of poor mans nitric which needs sulphuric and nitrates to be mixed and preferably distilled or frozen to create a decent work around, it's still not good for silver refining though.
I have never used or needed either methods as I have easy access to all the chemicals I need but try to remember them just in case.....you never know.
Keep up the good work and keep doing your trials as I'm sure your going to reach your goal fairly quickly.
 
i use poor mans AR very nearly on every project i do now. it takes some patience to master its use. it really is an invaluable tool to have when separating a mix of different metals. it is a devil to learn but once you have a good understanding of whats going on inside the reaction, it becomes very easy to control. i very seldom have a boil over now. :lol:
 
I just did a batch of gold filled scrap. 500 grams of material.

First, using a magnet, I seperated the magnetic material from the non-magnetic to process them seperately in two batches.

Then I remove any steel pieces such as pins and springs and any stones - magnet is helpful here also.

Then - INCINERATE - each piece to red hot. I take my time here and watch each piece as it heats up.

I had a nice GF pin, but the base metal was lead - as soon as I hit it with the torch it melted and stayed molten just from the heat of the melt dish.

When it finally solidified, I removed it from the batch - this is where incinerating each piece seperately really helps - for me.

Once all the material has been incinerated and cooled, I weigh it and record the weight.

Then I digest in hot - boiling - dilute nitric acid 50/50 nitric/dist H2O.

This takes some time - about 4 or 5 hours for this batch. I just keep adding small amounts of nitric until the fumes become very weak.

Then I let it settle overnight and siphon off the clear liquid in the morning.

Once the liquid is siphoned off, I add about 100 ml more nitric and distilled water to the foils and solids in the bottom and boil it real good for an hour or until no more fume are given off.

Then I add about 200 or so ml distilled water and dump all the liquid and solids into a buchner funnel through my vacuum filter rig to remove the last bit of acid liquid.

I then rinse the solids with distilled water - takes a while as the filter is pretty loaded up at this point.

I then remove the filter and solids and put everything into a pyroceramic dish (corningware). I use a small piece of damp paper towel to get all the mud out of the edges of the funnel and add that paper to the solids in the cornigware dish.

I keep a solution of AR in a beaker and I rinse the funnel with that AR to get the last bits of gold mud - process that later on.

Then I use a propane torch with about a 2 inch flame (low so as not to blow the solids out of the dish) and carefully incinerate the solids and the filter paper until all the paper is gone and each particle has been heated red - takes me about 15 minutes to do that.

Then I allow the dish to cool, and pour hydrochloric acid right in the cornigware dish. I use a bamboo skewer to loosen all the little bits that cling to the bottom of the dish.

Then I dump everything into a 1 liter beaker, using hydrochloric acid with a pipette with rinse the all the incinerate from the dish into the beaker.

I then pour a little of my AR solution into the cornigware dish to dissolve the last bits of gold from the dish - save to process later on.

I put a saucer (watchglass) on the beaker, put it on low heat and start metering in nitric acid with a pipette 1 or 2 ml at a time and start to dissolve the incineratred gold foils and mud.

Once all the gold dissolved (I hold the beaker up high and view the bottom to see if and gold is left) I added some urea to kill any excess nitric (not very much nitric left to deal with) and I added 1 ml of concentrated sulfuric acid to precipitate out any lead.

I add some more distilled water and let it settle overnight again.

Next day I set up my vacuum filter and using a pipette, I draw the clear gold solution up and transfered it - one pipette full at a time - to the funnel.

once all the clear solution was filtered, I remove the filtered gold solution from the flask and transfered it to a beaker and put the beaker in the fridge to cool down and get any chlorides to settle out. Then I re-set the filter rig and poured the rest of the gold and sludge into the filter.

I rinsed the sludge with distilled water until no more color comes out the bottom of the funnel, then remove that filter to my gold paper storage.

The liquid from that operation is pretty cloudy, so put in a whatman #5 fine filter paper and refilter the cloudy liquid.

If the liquid is still cloudy, I run it back through the same filter paper until it gets clear (my solution was green with bright yellow edges)

I did a spot plate test of the solution with some potassium thiocyanate and confirmed the presence of iron (turned blood red when the thio was added).

I then retrieved the cooled solution from the fridge (there was some yellow precipitate that had settled even though the liquid looked clear going into the fridge).

I ran that through the same filter paper and the final filtrate was clear and bright - green with yellow edges.

I put it in a 1 liter beaker and added about an ounce or so of sodium metabisulfite - the gold precipitated immediately.

I allowed it to settle overnight, then decanted the liquid off the gold powder and rinsed with boiling distilled water - pouring the wash water into a large beaker to catch any suspended gold (I collect the gold from these washings and add to my personal gold bead savings account).

once the powder was washed, I added hydrochlic acid and put it back on the heat.

then I added clorox to redissolve the gold powder for a second precipitation. Ended up having to add a few drops of nitric to speed things up.

After all the nitric was used up, there was still a few crumbs of gold powder that had not dissolved, so I added some more clorox and they disappeared.

I did not have any nitric to remove, so I added a drop or two of sulfuric (just for good measure) and filtered the gold solution again to remove any solids.

By this time the gold solution is very clear and the filter paper (whatman #5 fine) was nearly devoid of any solids.

I then precipitated the second time using oxalic acid - the gold is the best looking I have ever seen - it looks to be very pure - about 12 grams.

Edit once to add this link and correct some spelling errors To see the process for precipitating the gold with oxalic acid, please click on this link:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=11123

Hope this helps.

kadriver
 
kadriver :
" retrieved the cooled solution from the fridge" - "added about an ounce or so of sodium metabisulfite - the gold precipitated immediately"

Was it still cold at this point, or was it back to room temp after filtering?

Also - "once the powder was washed, I added hydrochloric acid and put it back on the heat"
" Ended up having to add a few drops of nitric to speed things up"

Is it possible that the heated solution drove off the clorox and you could have just added more clorox instead of the nitric at this point to do the same thing?

As I read your post, (nice details - thanks) I was fallowing along doing my own batch in my head. when I got to the nitric --- oops, I didn't have any. Ok silly me.

Once again nice detail. I'll likely save this to my notes.

Thanks
Ray
 
Sodbuster:

Yes, the solution came right out of the refridgerator and went right into the filter - the same filter I had been using all along.

The reason I used the same filter is because it had become loaded up with particulate from the previous filterings.

This causes the filtering to slow way down, but it helps strain out very small pieces of particles that would normally pass right through a new filter.

The filtrate runs nice and clear, but a drop at a time, even under vacuum.

Adding the Clorox off the heat would have promoted the chlorine retention and thus faster dissolution of the gold.

I could have just removed the reaction vessel from the heat and used Clorox all the way - but it was late and I got in a hurry.

It had been revealed to me that nitric can be added (just a drop at a time) to speed things up. Once all the nitric had been used up (reaction ceased and no more fumes) I switched back to Clorox to avoid having to remove excess nitric.

The nitric works very fast on the gold powder, especially if the solution is hot. But it is very easy to over shoot with the nitric additions, so I only add a drop at a time.

I'll post some pictures later on.

kadriver

Edit one time for spelling
 

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