Need help to deal with excess CL

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ahmadbayoumi

ahmadbayoumi

Well-known member
Joined
Sep 21, 2013
Messages
196
Location
Egypt
Hello Dears,

Few day ago, I tried my 1st batch of cell phones. I depopulated the cell phone boards from everything.

Then, I put all boards in AP and everything went good till I was trying to drop the gold using SMB.

Seems that used too much bleach thus no reaction occurred when added SMB.

Then tried to heat/evaporate the solution to drive off the excess bealch but seems it's not working.

I heated the solution for more than 3 hour with low heat to avoid boiling but still can't drop the gold.

I tried the stannous test and it gives the purple color which is rapidly disappeared.

Not sure what else could be done here .. PLS advise.
 
If it rapidly disapered that indicates you still have oxydent in your solution. Add some water and evaporate back down to your current level of solution then try SMB again.
 
Many thanks Barren .. I even tried this but nothing changed still can't drop the gold out of the solution
 
Your first post isn't clear to me. It says you depopulated the boards and put them in AP and you can't precipitate the gold. Could you please provide more clarity as to exactly what you did please as you mention bleach however there is no context?

This would really help as it would enable people to give you the best assistance based upon clear information.
 
How many boards or what was the weight?
How much gold do you expect and what volumes of reagents did you use?

Göran
 
Hello Dears,

Here are the details:
- Started with 10Ks of old cell phone boards.
- Depopulated all chips and other staff out of these 10Ks.
- Put the barren boards directly in AP (2 parts HCL 32%+1 part H202 3%) and air bubbler.
- Left the solution for 3 days with a addition of clean HCL every day.
- The solution went dark green as expected and almost most of the gold foils left the boards also as expected.
- Removed all the clean boards and collected the gold foils in one beaker.
- Washed the collected foils in HCL and water.
- Dissolved the foils using HCL+Bleach and got the yellow amazing color.
- Heated the solution for an hour without boiling to drive excess CL off the solution.
- Tested the solution with Stannous chloride and gave me +ve result but it then disappeared.
- Tried to precipitate gold with SMB but it was fizzing without any gold precipitated.
- Though I still have some excess CL so heated the whole solution again for another one hour.
- I got only 0.6 gram for very dark brown powder.
- Tried to heat again for another 2 hours and volume of the solution dropped down by about 200ML but no more gold precipitated.
- Repeated the stannous test and got the same results as before purple color which disappear rapidly.
- tried to add water and repeated the above steps but no change .. just fizzing then nothing.
- Tried to add HCL and again repeated the above steps but again no change .. just fizzing then nothing.

This is what I have done so far so don't know how to get the rest of gold out of the solution .. PLS help.
 
It sounds like you have done it by the book. Maybe there is a problem with your chemicals? Any nitrates mixed in with the SMB?

As a last resort you could always cement any precious metals on a piece of copper and then start over with the powders you get.

From 10 kilo of cell phone boards I wouldn't expect more than a few grams, and that is including the gold from inside the components too. If you got 0.6g gold already then it might be all that there is.

Göran
 
What is 10Ks? Is that 10 Kilos? Is that 10 boards? Is that 10 Lbs? You need to be more descriptive in what you are saying, text lingo doesn't go over well here on the forum.

2 to 1 mix of HCL and peroxide possibly dissolved some of your gold in your original solution.
 
Many thanks Göran .. do you mean to put a peice of copper will will force the gold to cement out at the bottom ?

In this case if I used an electric copper wire, would it be enough .. Also, do I need to add HCL ?

Many thanks Barren for your reply .. but K(g) is not a text lingo .. it's a standard term like gm for grams and ml for Milli liter .. anyway, sorry if it was not clear.

I tried not to use too much peroxide as I know that it may cause some gold to be dissolve.

The issue is not the gold that might be dissolved due to excess peroxide but it's in precipitating gold that dissolved by HCL+Bleach.

I want to know how to reclaim the gold out from the solution.
 
This is a good video on how to recover a mess or when gold doesn't drop.
https://www.youtube.com/watch?v=kt9KrV4z9Gk

You should do a search on the forum, it's been talked about a lot.
Here is two searches to get you started
http://goldrefiningforum.com/phpBB3/search.php?keywords=%22cementing+gold+with+copper%22
http://goldrefiningforum.com/phpBB3/search.php?keywords=cementing+gold+copper+mess

Göran
 
Sodium hypochlorite has to be boiled to make sure it is destroyed. Sodium hypochlorite boils (decomposes) at 101°C. It must reach this temperature to destroy the hypochlorite and get rid of the chlorine.
 
Too, the time needed to destroy it all depends on the amount of hypochlorite present. The more there is, the longer it will take.
 
Geo said:
Sodium hypochlorite has to be boiled to make sure it is destroyed. Sodium hypochlorite boils (decomposes) at 101°C. It must reach this temperature to destroy the hypochlorite and get rid of the chlorine.
Click to expand...

How do you get the water to attain a temperature of 101 degrees Celsius please?
 
anachronism said:
Geo said:
Sodium hypochlorite has to be boiled to make sure it is destroyed. Sodium hypochlorite boils (decomposes) at 101°C. It must reach this temperature to destroy the hypochlorite and get rid of the chlorine.
Click to expand...

How do you get the water to attain a temperature of 101 degrees Celsius please?
Click to expand...
It may surprise you, but by simply heating it. Ideally with a catch-pan in case a beaker cracks.

Because it's not just water, it's a gold chloride solution. Under the right conditions, 20% HCl for example may boil at up to around 108°C.
 
Ok, I get the theory behind that and understand it Jason, however isn't that all based upon altitude as well? Surely a temperature probe would need to be used to ensure that the liquid was in fact at a temperature in excess of 100 degrees Celsius instead of it being guesswork?
 
Yes. Pressure plays a part. The higher your altitude the lower the boiling temperature.

If you were high enough, or have access to a vacuum, you could boil water without heating it, but I don't expect it would make very nice tea.

Presumably the hypochlorite would boil out at a lower temperature too under low pressure, but i can't speak for the linearity between the two.

Geo has explained why it needs to be boiled. I've learned to hook up the cockroach to the freight train when he says so. If it were me I'd just boil it.

Sent from my Galaxy S7 using tapatalk
 
Hey it's no drama. If you're telling me that the impurities in the water are going to definitely raise the boiling point of the liquid above 101 degrees Celsius, and therefore the boiling is going to be effective then that's cool and groovy with me.
 
invest in an IR thermometer. Something like this one http://www.harborfreight.com/catalogsearch/result?q=laser+thermometer

thermometer.jpg
 
Thanks a lot Göran for your great help .. Seems that my last resort would be cementing gold out using copper .. will try this and will share the results with you.

Also, Many thanks for you Geo, however, I wonder how to boil the solution without losings gold.

One of the great lessons I learned here is "Don't ever boil a solution that is pregnant with gold" .. So how I would boil the solution to drive the excess CL off without losing the gold ?
 

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