HCL+Clorox ratio, conflicting numbers

[Jmk88]

I have a very simple method... (not claiming it’s mine but it’s what I do)

Cover your foils with about 35ml it bleach and cool the solution.

Then add 150 ml hcl. Heat the solution to about 30 Celsius and then wait for the bubbles to stop from the bottom.

Use a clear Pyrex pot so you can see once the bubbles stop. This means no more chlorine is oxidising from solution.

Then repeat. You need to repeat 5 times for half an ounce of foils.

Once you have decanted however many times needed the remaining chlorine will naturally oxidise what’s needed.

Keep it simple.

One more thing. Don’t forget to cool again before repeating.

 

[army_greywolf]

Hey my first post! I've lurked for years but I thought this was important to add. I'm a materials engineer by trade. One thing about pressure. Lower pressure, lower boiling point, lower activity. Higher pressure, higher boiling point. My simplistic method is to add the initial dose of bleach, wait for the gassing to stop, check for gold going into solution (mistakes happen) and then put the vessel on an old frozen yogurt ceramic cold plate.

I use a Duran 1000ml pressure vessel and 1 bar of pressure(argon) after dosing the vessel with 90ml of clorox. At the same time I try to keep the vessel between 5C and 10C for the duration. I have a lot to do most days so for me this is a hands off reaction that can wait for me to complete it indefinitely. I'm following formulas from this forum I am just making sure the chlorine gas remains in solution for the duration. Also, No errant chlorine gas is a good thing. The duran bottles and vessels are available on laboratory supply sites and I use a cheap regulator set at 1 bar, because pressure will build if for some reason temperature goes back up. I suggest encapsulation as well, which is something to protect yourself and your equipment while handling, a second layer of some kind.

I have tested Duran brand pressure vessels to fail and my compressor was unable to cause failure, at 12 bar the glass was still intact. But like anything, when your dealing with a gas, thats quite alot of stored energy so have some caution if you try this method.

 

[anachronism]

Great advert. That given you don't need a pressure vessel to do this properly.

 

[FrugalRefiner]

army_greywolf, how are you connected with Duran? We don't mind product recommendation here, but we like to know how members are affiliated.

Dave

 

[army_greywolf]

No connection. I have a friend who works at the science and surplus shop in Milwaukee and we were both talking about the process about a year ago and he strongly cautioned me on pressurizing glassware that isnt certified for it. So I did some googling and ended up ordering that particular glassware as it had the certs for use at pressure and temperature with every piece coming with its own certificate. I don't want to get hurt in my pursuits so that was my choice.

I already stated the reason. I just don't have the time to babysit the process, I'm not retired and I run a business already so time has to be spent wisely, that's all.

An edit: The first two responses as a supposition to my affiliation with a brand simply because I stated what I use for my own pressurized process is absurd. Thanks for the welcome. I joined back in 2014. I've never posted but have absorbed a treasure trove of information. I had some useful information for people in my situation who don't have the desire to babysit the process or potentially expose themselves unnecessarily to Chlorine gas. That's the other factor here, you minimize your exposure by quite a bit. I didn't think this would be met as it has been in such a dismissive way while trying to share some earned experience from myself on the process, and a MUCH safer method than dosing and release chlorine gas over and over again.

 

[anachronism]

Hi there

I'm not seeing the logic of this. Why would you wait until the Chlorine is not being produced before then pressurising it? It's been a long time since I've used HCl/Hypochlorite, but I honestly don't understand what would be achieved.

Thanks for your point about being unsupervised - that's the part I'm not getting, so please help me understand.

As an fyi I'm not retired either and I run a business too.

Jon

Edit: You edited your post as I was typing. Are you saying that the pressure vessel is for safety reasons? That would be logical to some extent, but the confusion arose because you did not explain this in your first post, and that's why you got the confused replies.

 

[FrugalRefiner]

An edit: The first two responses as a supposition to my affiliation with a brand simply because I stated what I use for my own pressurized process is absurd. Thanks for the welcome. I joined back in 2014. I've never posted but have absorbed a treasure trove of information. I had some useful information for people in my situation who don't have the desire to babysit the process or potentially expose themselves unnecessarily to Chlorine gas. That's the other factor here, you minimize your exposure by quite a bit. I didn't think this would be met as it has been in such a dismissive way while trying to share some earned experience from myself on the process, and a MUCH safer method than dosing and release chlorine gas over and over again.

Actually, it's not absurd at all. Since you've been a member for many years, surely you've seen that this forum is a target for spammers promoting their goods. One of my jobs as a moderator is to rid the board of such posts, hence my question. I didn't dismiss your post. I simply asked what affiliation you might have to the company so our members could evaluate your recommendation appropriately. Since it was your first post, I felt it was a fair question.

Dave

 

[army_greywolf]

Hi there

I'm not seeing the logic of this. Why would you wait until the Chlorine is not being produced before then pressurising it? It's been a long time since I've used HCl/Hypochlorite, but I honestly don't understand what would be achieved.

Thanks for your point about being unsupervised - that's the part I'm not getting, so please help me understand.

As an fyi I'm not retired either and I run a business too.

Jon

Edit: You edited your post as I was typing. Are you saying that the pressure vessel is for safety reasons? That would be logical to some extent, but the confusion arose because you did not explain this in your first post, and that's why you got the confused replies.

Alright, I do the first "dose" as you normally would, a small amount and wait. It is probably unnecessary but its done at room temp, as the process is traditionally done and I do this to do a stannous verification test, nothing more. The next dose is done at a very low temperature, 5C or so and its a high dose added slowly, I immediately turn the argon on and pressurize to 1 atmosphere and then leave it to react. This allows a larger amount of chlorine to continue the reaction uninterrupted at a slow(er) rate than it would at higher temperature, however it usually is the only dose required for complete reaction. This is my process for repeated reactions, simple as that. Finally to answer your question, it is a SINGLE dose, calculated from I believe lazersteve formula for absorbtion. It is probably quite a percentage too much but I'm not a chemist so I don't really know the margin. There are things I havent tried, it has been suggested to stir during the reaction and it could speed it up considerably. I dont have a stirrer or I would try it. That is the extent of my experimentation beyond what has been taught here.

ONE MORE EDIT: I use a cheap chinese regulator, and hdpe plastic tubing, and I vent the gas excess outside, away from human or animal exposure. I've heard horror stories of tissue scarring with even very small amounts of the gas and my wife has been INSISTENT about ppe and keep exposure to a minimum.

Lastly, I find it a bit of a stretch to find spammers erupting from a verified account from 2014 unless there has been a breach of accounts in the past in which case I really REALLY would like to have known that in an email or announcement. It's ok if you didn't notice the creation date the first time around, I don't hold that against you although the welcomes and so forth are generally good practice. After years and years of absorbing information I actually had something specific that I do and have not seen here that might be useful to someone else and I really wanted to help as a return on everything that has been shared to me.

 

[anachronism]

Lastly, I find it a bit of a stretch to find spammers erupting from a verified account from 2014 unless there has been a breach of accounts in the past in which case I really REALLY would like to have known that in an email or announcement. It's ok if you didn't notice the creation date the first time around, I don't hold that against you although the welcomes and so forth are generally good practice. After years and years of absorbing information I actually had something specific that I do and have not seen here that might be useful to someone else and I really wanted to help as a return on everything that has been shared to me.

I feel the need to respond to this.

If you've been a lurking member since 2014, then you should have seen how the forum operates, and gleaned a good understanding of both the right, and wrong ways to go about things.

Your initial post was unclear about your intentions and the reasoning behind it, and that was why things were asked for in the way that they were. That whole thing could have been defused with a simple "ahh sorry lads I didn't word that very well, here's what I am trying to get at" type of response.

Text isn't always a great medium, that I appreciate however if you're genuinely looking to get input, help and advice then it's the only medium you've got in terms of presenting yourself. Dave is completely correct in questioning you, he's a great moderator and if you would excuse the candour, it doesn't paint anyone in a good light to be beginning their journey on here by criticising the moderating methods and the way people should fit around you in how they write. It really should be the other way around don't you think?

Whenever I have to go back and edit a post to bring the correct context to the table I slap myself and think that I should have been clearer in the first place and the fault for how people have reacted to my poorly presented post is most often my own. 8) 8)

So, can we rewind this back and start this again?

Jon

 

[army_greywolf]

Lastly, I find it a bit of a stretch to find spammers erupting from a verified account from 2014 unless there has been a breach of accounts in the past in which case I really REALLY would like to have known that in an email or announcement. It's ok if you didn't notice the creation date the first time around, I don't hold that against you although the welcomes and so forth are generally good practice. After years and years of absorbing information I actually had something specific that I do and have not seen here that might be useful to someone else and I really wanted to help as a return on everything that has been shared to me.

I feel the need to respond to this.

If you've been a lurking member since 2014, then you should have seen how the forum operates, and gleaned a good understanding of both the right, and wrong ways to go about things.

Your initial post was unclear about your intentions and the reasoning behind it, and that was why things were asked for in the way that they were. That whole thing could have been defused with a simple "ahh sorry lads I didn't word that very well, here's what I am trying to get at" type of response.

Text isn't always a great medium, that I appreciate however if you're genuinely looking to get input, help and advice then it's the only medium you've got in terms of presenting yourself. Dave is completely correct in questioning you, he's a great moderator and if you would excuse the candour, it doesn't paint anyone in a good light to be beginning their journey on here by criticising the moderating methods and the way people should fit around you in how they write. It really should be the other way around don't you think?

Whenever I have to go back and edit a post to bring the correct context to the table I slap myself and think that I should have been clearer in the first place and the fault for how people have reacted to my poorly presented post is most often my own. 8) 8)

So, can we rewind this back and start this again?

Jon

I'd certainly appreciate a rewind. Has anyone tried a pressurized chlorine reaction before me? I haven't even found video or anything prior outside of .edu papers on the subject. So far it has been relatively flawless, minor burping issues were solved with a regulator, and using a chinese plastic regulator with plastic and viton parts has meant it does not get destroyed by the gases, although that wasn't the reason I bought it.

I strictly use this process for foils only. I have a fantastic source of industrial pcb scrap. Up until a few years ago we simply sold it as copper bearing blank boards believing what we were told that the gold foils would be so thin it was not worth recovery. This has turned out to be patently false and we had been taken advantage of (no surprise).

 

[FrugalRefiner]

Pressurized chlorine reactions were the norm for processing ores until cyanide replaced it. If you read some of the old refining books, it's well described.

Dave

 

[anachronism]

I'd certainly appreciate a rewind. Has anyone tried a pressurized chlorine reaction before me? I haven't even found video or anything prior outside of .edu papers on the subject. So far it has been relatively flawless, minor burping issues were solved with a regulator, and using a chinese plastic regulator with plastic and viton parts has meant it does not get destroyed by the gases, although that wasn't the reason I bought it.

I strictly use this process for foils only. I have a fantastic source of industrial pcb scrap. Up until a few years ago we simply sold it as copper bearing blank boards believing what we were told that the gold foils would be so thin it was not worth recovery. This has turned out to be patently false and we had been taken advantage of (no surprise).

Well, you get my vote for that response. Thanks.

Moving forwards then. HCl/Chlorox has most often been seen as the route for people who cannot get either Nitric acid or a Nitrate to make poor man's AR. It's pretty limited in the thickness of gold that it can dissolve and whilst it's perfect for the foils it's not much good for anything else.

It gases off a fair amount of Chlorine as you well know, just as AR gases off Nox. Good safety protocols usually revolve around fume extractors if the quantity is good enough, and then in some cases, depending upon where you live, a scrubber to get rid of the dangerous chemicals in said fumes.

Frankly that is why pressure vessels aren't necessarily seen as a good option, insofar as they aren't really necessary. There are some good posts on here about sealed reaction vessels which is a different idea altogether and those might be more appropriate to your needs. I think both the late GSP and 4metals have both shown pictures of their systems.

The beauty of these is that they can be used for both processes, along with others. I hope that gives you some constructive pointers.

Regards

Jon

 

[army_greywolf]

I'd certainly appreciate a rewind. Has anyone tried a pressurized chlorine reaction before me? I haven't even found video or anything prior outside of .edu papers on the subject. So far it has been relatively flawless, minor burping issues were solved with a regulator, and using a chinese plastic regulator with plastic and viton parts has meant it does not get destroyed by the gases, although that wasn't the reason I bought it.

I strictly use this process for foils only. I have a fantastic source of industrial pcb scrap. Up until a few years ago we simply sold it as copper bearing blank boards believing what we were told that the gold foils would be so thin it was not worth recovery. This has turned out to be patently false and we had been taken advantage of (no surprise).

Well, you get my vote for that response. Thanks.

Moving forwards then. HCl/Chlorox has most often been seen as the route for people who cannot get either Nitric acid or a Nitrate to make poor man's AR. It's pretty limited in the thickness of gold that it can dissolve and whilst it's perfect for the foils it's not much good for anything else.

It gases off a fair amount of Chlorine as you well know, just as AR gases off Nox. Good safety protocols usually revolve around fume extractors if the quantity is good enough, and then in some cases, depending upon where you live, a scrubber to get rid of the dangerous chemicals in said fumes.

Frankly that is why pressure vessels aren't necessarily seen as a good option, insofar as they aren't really necessary. There are some good posts on here about sealed reaction vessels which is a different idea altogether and those might be more appropriate to your needs. I think both the late GSP and 4metals have both shown pictures of their systems.

The beauty of these is that they can be used for both processes, along with others. I hope that gives you some constructive pointers.

Regards

Jon

It certainly does. I know I am late to the party on the concept. I have a couple issues some of which have finally been worked out. It may sound surprising but even though I live in the US I have had 62 power loss events this year according to my equipment. I only recently solved this with critical solar/battery backup switched circuits which would allow me to use a fume hood with good reliability. But I havent bought one yet.

My primary purpose in a pressurized reaction is to increase saturation for a complete reaction in one go, hands off. This lends me time to other things. The production of plated waste product has probably tripled in the last year or so from my source and I find myself in good repetition doing an AP copper strip of 40kg of pcb in any given week, staggered so that every day involves one or more buckets getting decanted, tested, cleaned and filtered so that I can add that batch to the hcl/bleach process the following day...and so forth. My own little assembly line. I also discovered by my own testing that each 3 gallon 31.45% AP setup can put 28kg of pcb gross through the process before it is spent.

I use a sealed 5 gallon gasketed bucket with a bubbler and an exhaust line, it works, ideally I'd like to vent it into a premade solution in a plastic drum to completely scrub the fumes. I haven't reached the capacity where I feel this would be warranted and I also think that when I do, it will be a scrubbing system for lab work.

 

[nickvc]

You are getting to the point when this hobby is almost a business with the quantities you are handling, my point is that with the amount of dangerous fumes you are potentially generating you need to look at stopping their discharge into your air and neighbors air, Jon’s advice about looking at sealed reactions and scrubbing the fumes needs serious consideration on your part, none of the gases we work with are good for you, your family or neighbors let alone the environment.
I wish you luck and hope the business thrives but make sure it isn’t at any cost.

 

[army_greywolf]

Exactly why its pressurized, quite honestly it produce gas for only the first few minutes. People who are dosing are producing multitudes more gas than I am.

I am wet scrubbing the output outside the work area using a NaOH solution and bubbling the output. It seems to work better than expected but the initial reaction only produces bubbling for a two or three minutes. If its cold enough it wont do anything but push some argon back out of the regulator. I cannot imagine doing this reaction in open air at room temperatures. I have seen videos where this happens and it's in someone's back yard. Like you I think immediately of the neighbors.

Oh and I'm not near a residence, and our nearest occupied neighbor is a auto body shop with gravel and grass separating us. I ALWAYS consider safety first when working on these projects. I know the processed amounts sound awesome, but its enig plating, barely a breath of gold on the surfaces so it takes quite a quantity to produce. Out of 10kg in a bucket, it will produce 1.8 to 1.9 grams on average. I'm obviously not getting rich processing it, but I can't justify getting 20 cents a lb either.

Another side project is to design a program that can determine the exact real estate of gold plating on ANY blank board and be able to give me a close estimate of recovery. Some day soonish lol. Anyways, I appreciate the concern and I hope I've explained better why I use this particular process over multiple dose process or sealed reactions. The biggest takeaway is it's effectively a single dose.

 

[nickvc]

Do your maths if as you say you are doing 40 kilos a week week in week out then with your yields you should have around 380 grams at the end of the year less your chemical costs and equipment, not a bad hobby.
You might also find better grade material in time so who knows where it could go.

 

[army_greywolf]

Do your maths if as you say you are doing 40 kilos a week week in week out then with your yields you should have around 380 grams at the end of the year less your chemical costs and equipment, not a bad hobby.
You might also find better grade material in time so who knows where it could go.

Me sentiment on the project is exactly that.