a new plan

[Geo]

ok, i had to scrap the plan to make my own thiosulfate. it takes too long and you have to stay with it. since its not too unreasonable on Ebay, i just ordered a couple of pounds of crystals. after reading on this patent : http://www.faqs.org/patents/app/20100111751#b i have decided that it is going to be more steps to the final product but with less time spent in the end. the two main components of the lixiviant (thiosulfate and ammonia) are easy enough to obtain. oxygen from the air and the formula calls for copper sulfate. i will buy a 1 pound can of root killer tomorrow. any thiosulfate can be used for the lixiviant but sodium thiosulfate was recommended. if i can make this work, i could very well start a small scale gold refinery here, using incinerated boards as my stock material. i know junk people from since i could walk thats still in business.

 

[kurtak]

This sounds interesting - I've read about it as an alternative for leaching ore's (along with SSN as an alternative)

My question is with incinerated electronics how does tin factor in - is it going to cause a loss due to colloids if not removed first?

Kurt

 

[Geo]

Ok guys, here's an update. The first part of my experiment was a huge success. I wanted to strip the gold from plated pins. The photos below are the pins after stripping. I placed the same weight in unstripped pins beside them to show the difference in color. The pins are not discolored, the gold has been removed. The silver color is the nickel barrier metal. The solution is a total wreck. I wont describe what i did until i can reproduce the effect without all the back tracking. Recovering the gold from solution is secondary to being able to put it into solution for me. I know that for a fact, I can get the gold out of solution.

 

[cnbarr]

Nice work Geo, I tried sodium thiosulfate Leach a couple of years ago, with less then stellar success I abandoned the project. With what I've seen in your thread has inspired me to try again!

 

[modtheworld44]

Nice work Geo, I tried sodium thiosulfate Leach a couple of years ago, with less then stellar success I abandoned the project. With what I've seen in your thread has inspired me to try again!

cnbarr

I'm getting pretty good results with my ammonium thiosulphate.I've been experimenting with it since Jan 20 and I got mine free with some free precious metals to boot.


Geo

Did ace have that ingredient? If so for how much?



modtheworld44

 

[Geo]

Ace Hardware brand Ammonia janitorial strength formula, 10% ammonium hydroxide. I actually added too much copper by accident and bubbled 96% oxygen through it all night. This morning, the solution was blue with green copper oxide solids. I have my overflow that i added hcl to and it dropped all metal from solution. The solids from the overflow solution looks like copper (brown powder). Ill digest the solids from the overflow and incinerate the metals from the main solution and then digest the solids from that and test to see where the gold ended up. At least i will know if I was removing gold before the overflow or after.

 

[goldenchild]

Patiently waiting 8)

 

[freechemist]

February 9th, 2014 Geo wrote:

Ok guys, here's an update. The first part of my experiment was a huge success. I wanted to strip the gold from plated pins. The photos below are the pins after stripping. I placed the same weight in unstripped pins beside them to show the difference in color. The pins are not discolored, the gold has been removed. The silver color is the nickel barrier metal. The solution is a total wreck. I wont describe what i did until i can reproduce the effect without all the back tracking. Recovering the gold from solution is secondary to being able to put itbinto solution for me. I know that for a fact, I can get the gold out of solution.

It's worth while to reread the posts written on the topic "Thiosulphate Dropped--Testing for PM?", begun about 2 years ago:

http://goldrefiningforum.com/viewtopic.php?t=12284
It's all about thiosulfate-leaching, followed by recovery of gold with iron(II)sulfate.

 

[Westerngs]

You can get concentrated sodium or ammonium thiosulfate solution at a camera shop. Buy Kodak black and white fixer, somewhere around $10 for enough to make about 5 gallons solution.

 

[niteliteone]

I have found my nitric supplier also carries it (sodium thiosulfate) for what I feel is a reasonable price.
http://www.sierrachemicalcompany.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=741&category_id=6&keyword=thiosulfate&option=com_virtuemart&Itemid=2

 

[solar_plasma]

Did you use only sodium thiosulphate in your leach or the method with ammonia and CuSO₄?

 

[Geo]

the lixiviant was sodium thiosulfate, ammonium hydroxide, and the patent i followed said to use any copper solution so i added 5mil copper nitrate. i know the nitrate kills the thiosulfate but it was a very small percentage and the patent named copper nitrate specifically. it only takes a very small amount of copper to get the reaction. copper sulfate is recommended but any copper solution will work.

 

[solar_plasma]

http://www.tandfonline.com/doi/abs/10.1080/10473289.2003.10466230

...maybe useful. In this abstract above they tell the concentrations used in the three leaches to extract most basemetals first (H2SO4), then pm's (thio) and at last Pb (NaCl/HCl?). Sn is not mentioned, but according to http://actamont.tuke.sk/pdf/2011/n2/2ficeriova.pdf, it will be leached together with Pb.

 

[Geo]

Thank you solar_plasma, this is not going to be like mixing a cake recipe. :shock: It's like learning a new language for me as i have no chemistry background. I will eventually have enough numbers to formulate a recipe type process for the chemistry challenged. There are some things I am working out. Like sodium thiosulfate is 148.21 g/mol. and water is 18.015 g/mol. At a 0.2 m solution, how many grams of sodium thiosulfate pentahydrate would i need for 20 liters of solution.

 

[FrugalRefiner]

There are some things I am working out. Like sodium thiosulfate is 148.21 g/mol. and water is 18.015 g/mol. At a 0.2 m solution, how many grams of sodium thiosulfate pentahydrate would i need for 20 liters of solution.

I'm not sure if you were actually looking for an answer, but...
We know that the sodium thiosulfate = 148.21 g/mol.
Since it's a pentahydrate, we have 5 water equivalents per mole of sodium thiosulfate, so multiply the 18.015 times 5 for a water weight of 90.075 g/mol.
So the total weight of one mole of sodium thiosulfate pentahydrate is 148.21 + 90.075 = 238.285 g/mole.
Now if we wanted to make 1 liter of 1 molar solution, we'd use 238.285 grams.
For one liter of .2 M solution, we'll need 1/5 that amount = 47.657 grams.
For 20 liters, multiply 47.657 * 20 = 953.14 grams.
EDIT
GSP has pointed out that the molecular weights I used are incorrect. You can see the correct weight in his post later in this thread.

Dave

 

[Marcel]

The most exiting thread in a long time! I can not contribute anything here, since I have zero practical experience with thyiosulfate recovery, but I did follow the concept for a long time now, because it appears to be a relatively safe cyanide alternative. Please keep us updated! Also please consider possible toxic or other hazards with the remaining substances and how they should be treaded/disposed in an enviromentally correct way! Maybe an analysis of the waste would clearify the required "skill level" of this process.

 

[Geo]

Actually, I was working on trying to figure it out through studying on my own but after 3 hours of reading and studying, I came up with wildy different outcomes. I really appreciate the answer. It's going to take some studying for quite some time before I'm able to formulate chemical equations. I will keep trying to figure out these things for myself but it is awesome that you guys are here to help me out.

Thank you Dave, It may have taken me months of studying to find the answer myself.

 

[solar_plasma]

I wanted to know, if only Na₂S₂O₃ alone will oxidize gold, so I did put some goldplating into a about 10% solution. After some days the colour has actually changed, which could be a sign for gold is dissolving. This may not have some practical use, just a curiousity. If it in some weeks will dissolve completely I will add the pics to this post.

 

[Loito]

I wanted to know, if only Na2S2O3 alone will oxidize gold, so I did put some goldplating into a about 10% solution. After some days the colour has actually changed, which could be a sign for gold is dissolving.

"In the absence of ammonia, gold dissolution by thiosulfate is passivated by the build up of sulfur coatings as a result of decomposition of thiosulfate on the gold surface (Pedraza et al., 1988; Jiang et al., 1993; Chen et al., 1993)."

"The oxidation of thiosulfate in aqueous solution by molecular oxygen, under ambient conditions of temperature and pressure, is known to be extremely slow and only occurs when copper (II) ions and ammonia are present (Naito et al., 1970)."

I have copied these two passage from the paper, which I have uploaded. I do not want to destroy your hopes, but i think it would take a while.

By the way. I finally started my expermiments on a thiourea leach. The leaching looked very promising. Tomorrow my steel cathodes will arrive and I try the electrowinning tests. I will start e new threat for that in a few days with some pictures.

 

[solar_plasma]

Then the change in colour on the right may be caused by this passivating layer. Thanks for the explaination!