Front and back

[Jmk88]

I don’t know I was struggling to filter it properly for some reason. I just couldn’t get it clear.

I’m not sure I don’t think silver chloride I think it’s filter paper.

Yes I don’t think the colour suggests any less than 95% but I will clean it up next week.

 

[kurtak]

is it silver chloride in it?

Or stannic tin ?

I think it’s filter paper

for sure not that --- it is metal salts - as in silver chloride - or stannic tin - or ???

The metal salts are in the form of colloids with are ULTRA fine particles - so fine that that they stay in suspension & tend to go through filters

if you don't eliminate then before dropping your gold they will just keep following you from one refine to the next

One way to eliminate them is to add a flocculant &/or coagulant to the solution before filtering

Edit to add; - with an acidic solution you need to use an organic polymer flocculant --- it takes very little & requires continuous stirring (which is where a magnetic stirrer hot plate comes in handy)

"sometimes" filtering with a charman plug filter will work - or "maybe" a wick filter

Did you put the first drop through the "proper" washes before dissolving the gold for the second refine ?

Bottom line - if you drop gold from a dirty solution (that has metal colloids) you ARE going to get a dirty drop - they NEED to be eliminated BEFORE the drop - or they will just keep following you gold drops

How you go about eliminating them depends somewhat on the kind of metal salt colloid is causing the problem :!:

Kurt

 

[Jmk88]

Thanks for the tip Kurt. Again, much appreciated.

Some more bed time reading! I am not so sure that it was tin as I magnet test every piece after I’ve cut it up.

I think silver chloride which would explain the odd colour on one side. Having looked at the filter I think it definitely is.

I have watman ultra fine filters but I find they take ages to drain. I use them mainly for my waste process.

 

[Jmk88]

And sorry Kurt, no I don’t ever wash my first drop I just immediately put it back into solution.

I didn’t wash the second drop properly either now I think about it. I just rinsed with boiling water not hcl :roll:

I have a lot on this weekend so was in and out of the workshop.

Plus I haven’t had any time off since Xmas so im beginning to fatigue a little bit in general.

I need some down time.

 

[Yggdrasil]

A magnet won't do much to Tin (Sn).
Its not magnetic as far as I know, tin roofs or tin cans on the other hand....
At least not ferromagnetic, it is weakly paramegnetic, which won't be noticed in minute amounts.

 

[Jmk88]

tin is very magnetic and I have a Small industrial magnet. It can pick up even the smallest bit of tin.

Tin is super magnetic to my magnet.

 

[Jmk88]

Look...

Sometimes clasps or replaced closers on the jewellery I refine have tin. They literally fly up when I hover the magnet over and they then burn instantly with propane.

 

[Jmk88]

I can lift it...

 

[jarlowski1]

You can usually find pieces that have tin if you are able to incinerate the material first. Tin melts around 230c. With jewelry I find it to be very beneficial to incinerate it first since there is so much organics in and on them (dead skin, grease, oil, hair, perfume, soaps ect.) . When you incinerate the jewelry you can isolate the pieces that start melt or show signs of something melting at these lower temperatures.

 

[Jmk88]

Yes I agree... that’s what else I was going to say. I incinerate in a dish first so I’m certain it’s not tin.

My sister just pointed out to me I’m very wrong and that food cans are actually steel based... :roll:

She said tin is not magnetic. Now I’m super confused as when I have like small bracelet chains they do react with my magnet then burn at super low temperatures....

Can anyone explain this? I thought this was tin?

 

[Yggdrasil]

Sorry man, what you show is tinned steel so called a tin can.
That is Steel(Iron, Ferrum) covered with a thin layer of Tin(Sn).
It has per se nothing to do with Stannum (Tin)(Sn)
Tin metal (Sn) is weakly paramagnetic.
Pure Tin, may be picked with a strong Neodymium magnet, maybe....
But the amount used to solder jewellery will not be noticable with a magnet.
The clasps may be made of non noble metals because of the stresses it are subjected to and price of course.

 

[Jmk88]

Thank you!

Understood. Yes that’s what she immediately said. She is about to start a PhD in chemistry.

We’re cut from very different cloths.

 

[kurtak]

I incinerate in a dish first so I’m certain it’s not tin.

incineration does not eliminate tin - if there is tin involved such as solder joints or (gold plated) clasps that are made of tin the tin will melt due to its low melt point - though tin has a low melt temp it has a very high boiling point which is 2,602 C (4,716 F) - in other words it has to get even hotter then that before it burns up (vaporizes)

Tin is a refiners nightmare due to its turning to stannic tin when nitric is used (whether straight nitric or nitric in AR) with the stannic tin being the problem I explained in my other post (staying in suspension &/or passing though even the finest filters)

Once you have it - it is very difficult to get rid of - it likes to haunt you (likes to keep following your gold) it needs to be eliminated one way or another --- doing a (simple) HCl (hot) wash will not get rid of it

Though tin (the metal) dissolves in HCL --- stannic tin does not

When dealing with gold plated - gold filled & even "low" karat material you are likely to run into tin

Besides solder, clasps etc. - you will run into it in the base metal alloys that the gold plating &/or gold filled is on - base metals of brass &/or bronze are common - some brasses can run between 1 - 5 % tin & bronzes can run as high as 5 - 15% tin (phosphor bronze being a common one that runs at 15% tin)

When you dissolve base metals that are alloyed with tin - & you dissolve those base metals with AR - due to the nitric in the AR - the result WILL be stannic tin - which then becomes the problem(s) already explained

It needs to be eliminated - or it will just keep following your gold

There are a number of ways to get rid of the (stannic) tin - which I don't have time right now to explain --- however - the normal water/HCl washes will not get rid of it

Though I can not say for sure - I am betting you have a stannic tin problem - not a silver chloride problem

Kurt

 

[Jmk88]

Hi Kurt,

I would appreciate any pointers on how to remove any tin prior to recovery.

Kind Regards,

 

[Jmk88]

Kurt,

Another question and some more info to help you out.

Would stannic not have dissolved in AR?

When I ran my recovery... there was purple mud which I have assumed to be gold nano particles. Other than this.. my recovery solution was completely clear.

You have me thinking now... the cloud did only appear after I had formed my AR which I assumed to be silver contamination not tin.

 

[Yggdrasil]

Stannic tin as in Stannic acid, Sn hydoxide, Sn2O4 formes when tin and Nitric reacts.
That is why we try to remove as much tin as possible prior to the use of nitric/AR.
Or if it is foils or powder just skip the nitric completely.

 

[Jmk88]

Do you think the purple colour was stannic?

I’m worrying now I’ve lost values.

I think I may have and Kurt is spot on. Would this explain the purple colouring of the past during my recovery?

 

[Yggdrasil]

I actually have a couple of bottles with purple solution sitting on a shelf.
The color was so nice that I took care of them.
Only later, I realized that it might be a variety of a dilute stannous test.
The amount of gold in there is so small I haven't made any plans for it yet.

Edited spelling error

 

[Jmk88]

Thank you! That’s put my mind at ease...

I was thinking that based on my Calculations I didn’t lose much... I find I’m always slightly under but I always allow 10% with filled items for wear.

 

[kurtak]

Jmk88

During the (work) week it is hard for me to post much due to having a day job - plus this time of the year deer & elk hunting season is coming up so I spend my week ends out in the woods scouting for the up coming hunting seasons - so my time to post much is limited

That said & as I said - tin is a gold refiners nightmare - if not properly dealt with - & that depends on when/where it is encountered during refining

I would appreciate any pointers on how to remove any tin prior to recovery.

Because of the "many" possibilities of when/where you will encounter tin in refining you are asking me to write a book - which I don't have time for

However - that said - if the tin is in the form of "tin metal" - such as tin solder you get rid of it by "first" dissolving it with "just" HCl - on the other hand if the tin is part of a base metal alloy (like brass or bronze) HCl alone wont solve the problem

Would stannic not have dissolved in AR?

NO :!: --- tin in AR does not get rid of stannic (tin) --- it "creates" stannic tin :!:

that is all I have time for today - I will "try" to post more tomorrow

Kurt