# Evaporation



## mjgraham (Aug 14, 2012)

Lately I have been wondering if I have been evaporating stuff and not really needing to. I have mostly been working with HCl/Cl process and the other day I decided to try to incinerate some filter papers that I had just to see, that went OK besides all the rookie mistakes on that but when I finally got all the ash and stuff in the HCl/Cl and filtered I had like 300ml of light yellow solution which showed a faint positive test. So I decided to evaporate it with just slight heat, got it down to about 50 ml all the while testing the vapor periodically for gold, which as far as I could tell were negative. Question one , at this point is this the solution I need to dilute 3x before smb? Question two do I really need to do this (I guess not) other than reducing the volume and losing some gold in the vapors that I would imagine would be so slight I might not see a test but after 200ml leaving might add up. I know it is good to remove excess Cl and SO2 from various stages of the processes but really am I just adding hours to a process that I don’t need to.. Just some thoughts
Thanks
Jarrid


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## philddreamer (Aug 14, 2012)

MJ, keep in mind that, if you use the HCl/Cl process, all you need to evaporate is the clorox. 
So, let's say, you started with 200ml of HCl and added 100ml of clorox, all you need is to evaporate 100ml of the solution, which will be your clorox because it evaporates readily. If on the other hand, you used the AR process, and you added too much nitrate, then you need to evaporate down to syrup and add some HCl, and so on...

Take care!
Phil


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## ericrm (Aug 14, 2012)

philddreamer said:


> MJ, keep in mind that, if you use the HCl/Cl process, all you need to evaporate is the clorox.
> So, let's say, you started with 200ml of HCl and added 100ml of clorox, all you need is to evaporate 100ml of the solution, which will be your clorox because it evaporates readily. If on the other hand, you used the AR process, and you added too much nitrate, then you need to evaporate down to syrup and add some HCl, and so on...
> 
> Take care!
> Phil



i would even go lower then that ,chlorox is 5% sodium hypochlorite ,even if you put 100ml you would only need to evaporate 5ml since the rest is water... (but that not exact since it is a chemical reaction that make the chlorine and i dont know how to count it...


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## philddreamer (Aug 14, 2012)

That's correct Eric; but, (to be on the safe side), my point was, he should evaporate the amount or close to the amount of clorox he added until he learns. 
Thanks for your input! 8) 
Phil


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## Palladium (Aug 14, 2012)

Two notes i would add just for points. Your free cl will exist in the water even though you have hcl and bleach in there also. When i do hcl/bleach i add about 50% excess water to mine so the cl is absorbed into the water and is not just released as gas.
The other note being the more concentrated you evaporate the solution the better and coarser the gold drops making for easier settling and clean up. If you only have a small amount of gold and drop it from a real diluted solution it will take for ever to settle out and be very very fine making life miserable.


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## mjgraham (Aug 14, 2012)

OK that helps me out, I'd say I have been going a little to far in the process at any rate, well like I already knew I need to keep track of the amounts of stuff a little better. Here is where I am at with it at any rate, had aprox 50ml solution , knowing there is not to much in there put 0.5g of SMB in , came back about an hour still yellow, tested positive, got to thinking needed to dilute it, added about 50ml H2O went clear quite quickly then after a couple hours noticed a small haze on the bottom will check later on. May just have to let it settle and re HCl/Cl it. I know there was not much to start with coupled with all the uh-oh moments, still a lot to learn.
Thanks all for the input
Jarrid


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## philddreamer (Aug 14, 2012)

Very true Ralph!
These and other "points" he will be learning thru his trails & errors. Though, he can minimize those by searching thru the posts before starting a process. 8) 
Thanks!
Phil


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## jimdoc (Aug 14, 2012)

Jarrid,

Could you correct the spelling in the title of this thread?
It should help in future searches.

Jim


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## Palladium (Aug 14, 2012)

Let me clarify that some. I add the extra water at the beginning to help keep the free cl in solution so it does its work more efficiently. Then when i evaporate the excess water before precipitation it expels the free cl from solution and concentrates it for precipitation. Once evaporated for precipitation your solution is concentrated, the free cl is gone, and you have less waste solution to deal with. It's more about efficiency for me with the free cl instead of it gassing off and me having to keep adding more bleach to my solution. I like to keep as many variables out the situation as possible and the bleach to me is a lets use the word contaminate. Water is water and can easily be gotten rid of, the sodium hypochlorite can't. When dealing with small amounts of foils this is not true, but when you have a large volume it saves from adding all the extra's.


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## mjgraham (Aug 14, 2012)

jimdoc said:


> Jarrid,
> 
> Could you correct the spelling in the title of this thread?
> It should help in future searches.
> ...


Sorry about that , I would love to, I don’t know how exactly( just hit edit on my post? ) but I think someone has already fixed the first post. Unless I am just looking at all completely off.


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## Palladium (Aug 14, 2012)

I think oz probably did it.

Yes it was me, guilty as charged, Oz


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## mjgraham (Aug 14, 2012)

Palladium said:


> I think oz probably did it.
> 
> Yes it was me, guilty as charged, Oz


That is what is so great about this place, people help you when you don't even know you need it.


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## Franciz (Sep 12, 2012)

mjgraham said:


> Palladium said:
> 
> 
> > I think oz probably did it.
> ...




Fully Agree :lol: :lol: :lol:


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## Geo (Sep 13, 2012)

i would like to add this for readers following this thread. Harold has repeatedly said that he precipitated his gold from very concentrated solutions. as far as i know, you can evaporate AuCl to its crystal form without losing any gold as long as the heat isnt too high. values are lost when you boil a solution in an attempt to evaporate. boiling solutions give off an aerosol spray from the bubbles bursting which gets whisked away by the thermal currents rising from your solution.we have seen pictures posted of AuCl crystals on the forum before and if i remember correctly, they were almost red in color. if you have a weak positive for gold in a large volume of solution (subjective as to volume considering the amount of gold dissolved) it would help to evaporate the solution until the stannous test is a strong positive at least.


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## Oz (Sep 13, 2012)

Geo said:


> We have seen pictures posted of AuCl crystals on the forum before and if i remember correctly, they were almost red in color.


Here you go.


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## Geo (Sep 13, 2012)

thank you Oz. 8)


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