# HCL+Clorox ratio, conflicting numbers



## sng

I've read that the correct ratio is 4parts HCL to 1 part Clorox in a few places, but lazersteve said he used 100ml HCL+10ml Clorox in this thread: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=416&p=3486&hilit=clorox#p3486.

100ml/10ml is nowhere near a 4:1 ratio. Usually I'd trust the most commonly cited ratio (4:1), but lazersteve seems to know his stuff and could very well be correct over everyone else.

Also, how much HCL+Clorox is needed per unit of gold powder? I've looked in the reaction list of this document (http://www.scribd.com/doc/2887935/GOLD-REFINING-FORUM-HANBOOK-VOL-1) and done a search of "acid+clorox" but have been unable to determine how much needs to be used. Can I add slowly and stir until the gold is fully disolved?

Also, while you're here, how much SMB is needed per unit of dissolved gold. I'll try to find this myself, but am asking anyway in case someone decides to answer before I can find the answer for myself.

Edit: SMB= Sodium MetabisulfAte or MetabisulfIte? I've seen it written both ways... one has to be the wrong chemical, no?


----------



## Barren Realms 007

I wouldn't go by a known ration I feel you have this confused with AR. You want to add just enough to dissolve your gold and then warm the sloution or let it set outside till the chlorine has disipated and then addd your SMB to percipitate you gold out. Generly gram of SMB per gram of gold. You want metabisulphite not sulphate.


----------



## Sucho

check these links, compare molecule structures and try to make equations...gold halide(cl-) complex is reduced by SO2 ... from which salt could SO2 develop,when you are using water and HCL ? or try the search box ..

sodium metabisulfite

http://en.wikipedia.org/wiki/Sodium_metabisulfite

sodium sulfite

http://en.wikipedia.org/wiki/Sodium_sulfite

sodium sulfate

http://en.wikipedia.org/wiki/Sodium_sulfate


----------



## sng

I know what Aqua Regia is, what piqued my interest in HCL+Clorox was that it enabled me to dissolve gold without making Aqua Regia. I'll need nitric acid to separate inquarted silver and gold, but HCL is much easier to find (and less expensive) than nitric. Bleach is obviously more readily available than any acid used in gold refining.

I'm confused, how do I make a HCL+Clorox solution if I don't know how much of each to add?


Edit:

HCL can not dissolve gold. This means that the chlorine is what dissolves the gold and that the HCL is just there to dissolve the chlorine? If too little HCL is used the chlorine will escape in gaseous form, causing the dissolved gold to reprecipitate. If too much HCL is used, the chlorine will be too dilute to dissolve the gold powder. Am I overthinking this?


----------



## Sucho

its enabled by free chlorine , because in bleach is included this compound

http://en.wikipedia.org/wiki/Sodium_hypochlorite 

which interracts with your acidic solution and free chlorine is enabled- chlorine gas could oxidize gold


----------



## sng

I understand how the reaction works. What I need, is a recipe. Without a recipe I have no way to know whether to add more HCL or more bleach should the reaction stop before the gold is fully dissolved. Trial and error is a sure way to use more material than necessary. Everything else pertaining to gold refining has had a general recipe to follow, while HCL+Clorox's recipe is "HCL+Clorox".


----------



## Barren Realms 007

There is no set recipie for this trial and error and experience is how you come up with your formula.


----------



## Sucho

it depends on concentration of NaOCl...you can count it...i have never used hydrochloric-clorox, but in my opinion , you can use 1:1...or you can see it during reaction...its all about equilibrium ..you can speed up/slow down/end the reaction by adding reactants/products/catalysators/etc...every system is trying to achieve state with the lowest energy...


----------



## sng

Ok... not the answer I was expecting . So long as adding too much of something can't somehow harm the gold, I think experimentation could be quite fun. Worst case, I waste acid or bleach but still end with dissolved gold right? And Sodium Metabisulfite quantity won't change because that is dependent on the amount of dissolved gold which will remain unchanged regardless to how much HCL/Bleach I use. 

I guess I'll just start small. Cover gold powder with minimum amount of HCL, add small amounts of bleach, and stir often. 

TYTY


----------



## Barren Realms 007

sng said:


> Ok... not the answer I was expecting . So long as adding too much of something can't somehow harm the gold, I think experimentation could be quite fun. Worst case, I waste acid or bleach but still end with dissolved gold right? And Sodium Metabisulfite quantity won't change because that is dependent on the amount of dissolved gold which will remain unchanged regardless to how much HCL/Bleach I use.
> 
> I guess I'll just start small. Cover gold powder with minimum amount of HCL, add small amounts of bleach, and stir often.
> 
> TYTY



Yes to your last part.


----------



## oldgeek

I have used the 4:1 ratio without issues.
I added the bleach to the HCL in increments.

An important part to remember before using SMB to drop your gold, is to dilute your AuCl3 solution 3 times over with water. You may need to refilter after dilution as some silver chloride may form (I learned this from a video on lasersteve's website, you should also watch it.)

Mix up your saturated SMB solution and add some to your AuCl3 while stirring. You then test your AuCl3 with stannous Chloride to ensure you have dropped all of your gold.

I learned ALL of this from lasersteve's guided tour. (link provided below)

http://goldrefiningforum.com/phpBB3/viewtopic.php?p=6873#6873 

Click on the "reactions list"


----------



## lazersteve

Here's a few old links:

How much HCl and Clorox to dissolve gold?

Guided Tour

The bleach is not all added at once, it's added in small increment as I stated before. If you add a large dose (eg: ~100mL), you will only succeed at making a big cloud of chlorine which does nothing towards dissolving your gold, but will choke you very quickly. The only chlorine that works on dissolving the gold is chlorine that is in the solution, not the chlorine that is floating around your lab. 

Add the small dose (eg: 10-20mL) and stir until no more fizzing occurs, then let the solution settle a minute and see if the gold is all dissolved. If it is not then add another small dose of bleach, if the gold all dissolves on the first dose, don't add any more bleach. 

Too much bleach will prevent the gold from precipitating and will also interfere with the stannous chloride test.

Steve


----------



## donnybrook

I was told many years ago that the ratios (SMB in distilled water) to recover gold in a prepared solution was 110grams of SMB to 1 litre of solution of distilled water to recover 60 grams of gold.

Your weight measures including that for an ounce of gold (28 as opposed to 31.2 grains) are different so you may have to convert. That would be a laboratory formula and not necessarily what I would use myself. My solutions are broken down with 10 parts water before adding the SMB.

donnybrook


----------



## Gratilla

Some time back I tried both HCl + Clorox (5%+/- NaClO) and HCl + Industrial sodium hypochlorite (24%+/- NaClO); the former is also referred to as the iGoli process put into the public domain by Mintek of S Africa to discourage use of mercury by artisanal miners. I would offer you a copy of this doc, but I can't find it. A google should turn it up though.

Irrespective of the recipe, the "trick" is to add the NaClO in small increments (in line with lazersteve's suggestion) while stirring (and holding your breath). Trying to speed the process by adding large amounts of NaClO quickly will only result in a large off-gassing of Cl, wasting your chemicals and endangering your health. Basic chemistry suggests that running the process in a closed system should minimize off-gassing. I think Mintek has some equipment for this.

Also, excess oxidants (NaClO in this case) will interfere with reducing reactions such as precipitation and the stannous test. For the same reason the nitric acid (an oxidant) in AR needs to be eliminated before attempting precipitation with a reducing agent.


----------



## wwjd72

I AM NEW AND IT IS SOME WHAT HARD TO FOLLOW YOUR WORDING .I wish someone could speak like ghetto aka: at lows buy ... use i cup to 1/4th of a cup of hydrogen peroxide in your aqua Regina aka gold extraction through use of chemicals. also I just put my misc stuff in a solution of "3m heavy duty bowl cleaner"yes toilet stuff. at 4 am.active ingredient is hydrochloric acid.


----------



## Oz

Wwjd72,
If you wish conversation like that go to the ghetto, you will not find it here. If you want professional opinions about refining, stick around. If you wish to speak that way and wish others to answer you in kind, I will personally remove you from our site as you will have no reason to be here since such a sloppy method of conversation when dealing with hazardous chemicals can get someone maimed or killed.

Shape up or ship out!


----------



## joem

wwjd72 said:


> I AM NEW AND IT IS SOME WHAT HARD TO FOLLOW YOUR WORDING .I wish someone could speak like ghetto aka: at lows buy ... use i cup to 1/4th of a cup of hydrogen peroxide in your aqua Regina aka gold extraction through use of chemicals. also I just put my misc stuff in a solution of "3m heavy duty bowl cleaner"yes toilet stuff. at 4 am.active ingredient is hydrochloric acid.


Even I am newer at this and I still don't get what you are asking?
aka: what? :shock:


----------



## rustyle

lazersteve said:


> Here's a few old links:
> 
> How much HCl and Clorox to dissolve gold?
> 
> Guided Tour
> 
> The bleach is not all added at once, it's added in small increment as I stated before. If you add a large dose (eg: ~100mL), you will only succeed at making a big cloud of chlorine which does nothing towards dissolving your gold, but will choke you very quickly. The only chlorine that works on dissolving the gold is chlorine that is in the solution, not the chlorine that is floating around your lab.
> 
> Add the small dose (eg: 10-20mL) and stir until no more fizzing occurs, then let the solution settle a minute and see if the gold is all dissolved. If it is not then add another small dose of bleach, if the gold all dissolves on the first dose, don't add any more bleach.
> 
> Too much bleach will prevent the gold from precipitating and will also interfere with the stannous chloride test.
> 
> Steve





Hi Steve,

I think I have too much clorox in the solution. How do I correct it? I have gold dissolve in solution but not drop much when add SMB. Please help!


----------



## butcher

Heating the reaction will drive excess chlorine from solution, chlorine is a gas, most gases are much more soluble in cold dilute solutions, these same gases are not as soluble in hot solutions and are driven off by heat, oxygen in water is similar we can drive oxygen out of water with heat.


----------



## variable

lazersteve said:


> Here's a few old links:
> 
> 
> The bleach is not all added at once, it's added in small increment as I stated before. If you add a large dose (eg: ~100mL), you will only succeed at making a big cloud of chlorine which does nothing towards dissolving your gold, but will choke you very quickly. The only chlorine that works on dissolving the gold is chlorine that is in the solution, not the chlorine that is floating around your lab.
> 
> Add the small dose (eg: 10-20mL) and stir until no more fizzing occurs, then let the solution settle a minute and see if the gold is all dissolved. If it is not then add another small dose of bleach, if the gold all dissolves on the first dose, don't add any more bleach.
> 
> Too much bleach will prevent the gold from precipitating and will also interfere with the stannous chloride test.
> 
> Steve



After adding second small dose of bleach and gold is still undissolved what would one do? Steve says one should stop. Should one pour solution from original vessel to a second one and put more fresh 4:1 ratio Hcl + bleach in original vessel to finish the process. So, as long as we have 4:1 ratio, there should be no problem in dropping gold with SMB from our solution in question? Would each addition of bleach (now first + second vessel) create a cumulative effect where it would interfere with SMB drop? Or putting 4:1 ratio of in the same vessel should work as long as it's not only bleach? I'm asking since I think I put too much bleach last time I processed my powder from sulfuric cell ( was not digested after first addition to was putting more bleach to finish the process ). More like 4:2.5. I did get a partial gold precipitate on the bottom of my vessel. Also, SnCl2 test is negetive for gold. However, I understand the this could be false negative due to too much bleach. Also, the vessel still shows little bit of yellow/bownish after smb drop (sorry no picture). It did seem like I had 2x treated original black powder from sulfuric cell to start with. Should I stick a piece of copper and see what else comes out or try something else such as dilution with water or anything else which would work same way to reduce bleach concentration?


----------



## butcher

variable,
That was so many questions at once I do not think I could answer them all, if you have many questions you should spend more time studying and doing small experiments.

I will not try to answer the questions, but I will try to get you to see something I see.

HCl will not dissolve gold; gold is far below hydrogen in the reactivity series of metals, HCl in not a strong enough oxidizer to dissolve gold. Nitric acid can oxidize gold, or chlorine gas can oxidize gold (pry away an electron from gold’s atom).

Sodium hypochlorite (Bleach) is an alkali solution; the sodium hydroxide NaOH involved in the bleach keeps it caustic enough to keep the chlorine in the solution of water.

When you mix the HCl acid with the Alkali Bleach you form chlorine gas which can oxidize gold in solution, but we also lower the acidity of our acid with every addition of bleach forming salt out of our acid (HCl + NaOH --> NaCl + H2O), also the chlorine is a gas that wants to bubble out of solution, so we can here where too much bleach at once can destroy our HCl, and make table salt, and waste chlorine as gas, also the lower the acidity the easier the chlorine would stay in solution, temperature also plays a major role in how the chlorine stays in solution.

So when we have gold fine powder or foils (this method has a very hard time trying to dissolve solid bigger pieces of metal), the gold in the HCl is oxidized by the chlorine gas (formed from the acid and bleach), this chlorine take’s electrons from the gold atoms, the gold becomes an ion (Cation), this gold Cation joins with three chloride (Anions) to form a soluble salt or compound of gold chloride, or dissolved gold in solution.

Now we already discussed loss of chlorine gas through gassing out of solution, and of our acid being neutralized, by the alkali solution, so we need to be aware we need free HCl acid in solution, and just enough chlorine gas to do the job, we can add a little more bleach a little at a time to keep the reaction going.

I believe far too often when we begin learning, recovery and refining, that a newbie’s we tend to way over use acids and solutions, we are impatient, and want to see something happen now, or we do not give it time to react, and do not know how much to add or what the reaction would even look like, much of our solutions or acids and reagents are wasted, and we create other problems for ourselves by using too much.

I would add the gold to the acid, and add the sodium hypochlorite just a little at a time, (personally, I prefer a warm solution), give it time, the reaction may not be very visible maybe only a few tiny bubbles.

Points to consider we want our solution acidic (bleach raises pH), so we must have enough acid to keep it acidic, also adding too much bleach to fast just gasses off most of the chlorine before it has time to react with the gold (also making salt out of our acid), to high of a temperature will also gas off our chlorine faster, but also too low of a temperature take so much longer for the reaction to occur and dissolve our gold, overuse of bleach can leave oxidizer in our solution when we go to precipitate the gold, I believe many times members have also used so much sodium hypochlorite the may have also raised the pH very close to neutral (mainly just dissolved salts, not much free HCl acid to help drive off chlorine), in this case they may have to evaporate the solution much farther than they normally would have to (until the acid concentrates enough to drive off the chlorine in this solution), at this point they may have salts forming from the solution becoming so saturated with salt, a little acid may help in this case.

Now so not only will gold use up your acid in the reaction but the NaClO can also use the acid up, it would be interesting to know what the pH of some of these guys solutions are, that are having trouble with too much chlorine left in solution before they precipitate (my guess is they may have no free HCl and they may not have a very acid solution left to drive off chlorine easily.

When I use HCl/NaClO I do not follow a certain ratio, but if I did I would look at what was recommended, and use that as a guide only, I would still have plenty of HCl and add the bleach on a small proportion at a time, (using the ratio as a guide to help to understand when I may be adding more than needed), but also I am not suggesting others do it this way.


----------



## kkmonte

Also, I think you might have mis-read what Steve typed. I'm pretty sure he said that if all of the gold was dissolved after the first addition of bleach, do not add any more. Basically, you need to use however much you need to use, but just don't think add any extra if you don't need to.

Question for Butcher, do you really re-type those types of responses (your last one here above)? Or do you have a notepad/txt document that you just copy and paste it into the forum? I've seen you type that information so many times, if you are really uniquely typing it each time, !!! Good for you! You have more patience then most!!! 

-Ken


----------



## variable

Yes! Steve did say if the gold is dissolved than stop - I've misread it. But, than again, we don't want to go over the limit if it's not. Thanks for the time answering my questions + so quickly. I think i'll give my HCl + Bleach solution more time next time since it attacks surface of gold particles somewhat slower than AR with smaller Bleach additions. Probably, this way I won't overdo it. I think I understand the process. That is, if there is alot of Cl gas in the lab area it's not where it's suppose to be since it needs to be in the solution to get the work done and not out of it.


----------



## butcher

Yes I guess I do repeat the same old thing, yes I do type them every time, I never had a memory, so I really do not remember what I said before, and really would not know where it was to be able to copy and past it, I guess every one of us answer the same old questions over and over, and people keep asking the same old questions over and over, maybe that is not a bad idea, I have been told lately I keep answering the same old questions spending too much time typing, so I suppose from now on I should just copy and paste my answers.

Read Hokes book and study the forum.
Read Hokes book and study the forum.
Read Hokes book and study the forum.
Read Hokes book and study the forum.
Read Hokes book and study the forum.
Read Hokes book and study the forum.

Wow that is much simpler, and a member would have all of his questions answered.

Read Hokes book and study the forum.


----------



## Traveller11

It is also possible to put gold into solution as a chloride using bleach (NaClO) without using HCl. Bring the pH of the bleach down to just above neutral by small additions of HCl or even acetic acid (vinegar). This will make hypochlorous acid (HOCl). To this, add sodium or calcium chloride to make chloride available for the reaction. This solution, plus whatever material you wish to put into solution, must be placed into an airtight container with ALL air excluded and then agitated or rotated to maintain maximum exposure.

The reason for excluding air is that hypochlorous acid (HOCl) is very unstable and, without backpressure on it, it will lose its oxygen atom to the air and become HCl, instead of becoming part of the dissolution of gold process.


----------



## mrsanders02

Butcher, So just to be clear, what I should do is : [b]Read Hokes book and study the forum.[/b]?
What a novel concept! I am going to try to *Read Hokes book and study the forum*.
Thanks for all you do, I love this site, and am starting to really like this hobby. I am at the point of (almost) getting ready for my first melt down of collected powders from multiple small scale processes.
I expect about .75 to 1 grams, stuff is still wet right now so I am not sure. Wish me luck.
Thanks again, oh and : Read Hokes book and study the forum.


----------



## butcher

mrsanders02,
I do wish you luck, but since your doing your homework, it is not as much about luck. as it having an understanding of what you are doing, that and a little practice with what your learning, I think you will do just fine, at least you are on the right track towards success.

I do not like working with very small batches, if I do I will normally save the powders from the small batches up until I have more to work with, seems like a little gold is left behind here and there (recovered later), this is more noticeable on many very small volumes than it is on one larger batch.


----------



## Anonymous

As Butcher and others have said, I don't use a fixed "ratio" of acid/bleach. I cover the gold in acid then add bleach "to taste" until it's all dissolved.


----------



## Don in Mindanao

try this web page :

http://www.ehow.com/how_10075085_leach-gold-ore-chlorination.html

it says 15% bleach (sodium Hypo chlorate) 33% Hydrochloric Acid 52% water and add enough to cover your ore. and to use an ORP meter to maintain 1,000 mv and to not go lower than 400 mv the reaction is complete when the voltage does not change when you add more HCl but read the webpage it has a moderate detail about the only thing missing is the temperature of the hot water
the page can tell you better than i can

http://www.ehow.com/how_10075085_leach-gold-ore-chlorination.html


----------



## squarecoinman

Don in Mindanao said:


> try this web page :
> 
> http://www.ehow.com/how_10075085_leach-gold-ore-chlorination.html
> 
> it says 15% bleach (sodium Hypo chlorate) 33% Hydrochloric Acid 52% water and add enough to cover your ore. and to use an ORP meter to maintain 1,000 mv and to not go lower than 400 mv the reaction is complete when the voltage does not change when you add more HCl but read the webpage it has a moderate detail about the only thing missing is the temperature of the hot water
> the page can tell you better than i can
> 
> http://www.ehow.com/how_10075085_leach-gold-ore-chlorination.html



Don I am not sure if you did read all the post on this subject but I am sure you have the best intentions by giving this link, however all the information needed is here on the forum and at the forum you will know that it is correct, if not a moderator will make sure that people will not make mistakes and correct the problem.

If you send people to other places you should be sure that the information you give is correct.
and when you quote you should also make sure it is 100 % correct, we are working with chemicals and small mistakes can be dangerous, some people are lazy and do not read everything. They just skim pages and then make a mess.

you write 15 % bleach ( Sodium Hypo chlorate ) the website writes (sodium hypochlorite) 
You write 33 % Hydrochloric Acid webside writes 33 % hydrochloric acid
you write 52 % water the website writes nothing about water in point 3 Rebecca smith writes that you should put the ORP meter in the water mixture 
now I know that Rebecca Smith ( the one that wrote the article is a specialist in greenhouses and home decor ) but she never write anywhere to ad water , so my question is do I ad water first, do I pour the water in the acid, do I pour the bleach first then the acid and the water . Ok I am sure you get my point.
My next question is, can you explain the difference between Sodium Metabisulphate and Sodium Metabisulphite.

On the same website there are other instructions for the same process that will mix Bleach and HCL in another mixture that would make me worried 
I would therefor not link to another place is i would not be sure it would not harm or mis inform people.

last but not least welcome to the forum, do use the search and try to find Hoke book it is a very good book for beginners and take the guided tour 

squarecoinman


----------



## butcher

I agree, not only would that not work it is very dangerous, Rebecca has read something somewhere that she has no clue about, trying to repeat that information she is giving people misinformation, that not only, would not recover any gold out of the rock, it could actually kill somebody who tried to follow the instructions, or the procedure as written, the waste treatment procedure can also harm others.


----------



## Traveller11

"It is also possible to put gold into solution as a chloride using bleach (NaClO) without using HCl. Bring the pH of the bleach down to just above neutral by small additions of HCl or even acetic acid (vinegar). This will make hypochlorous acid (HOCl). To this, add sodium or calcium chloride to make chloride available for the reaction. This solution, plus whatever material you wish to put into solution, must be placed into an airtight container with ALL air excluded and then agitated or rotated to maintain maximum exposure.

The reason for excluding air is that hypochlorous acid (HOCl) is very unstable and, without backpressure on it, it will lose its oxygen atom to the air and become HCl, instead of becoming part of the dissolution of gold process."



There are none so blind, as those who will not see.


----------



## Evan2468WDWA

Traveller11 said:


> It is also possible to put gold into solution as a chloride using bleach (NaClO) without using HCl. Bring the pH of the bleach down to just above neutral by small additions of HCl or even acetic acid (vinegar). This will make hypochlorous acid (HOCl). To this, add sodium or calcium chloride to make chloride available for the reaction. This solution, plus whatever material you wish to put into solution, must be placed into an airtight container with ALL air excluded and then agitated or rotated to maintain maximum exposure.
> 
> The reason for excluding air is that hypochlorous acid (HOCl) is very unstable and, without backpressure on it, it will lose its oxygen atom to the air and become HCl, instead of becoming part of the dissolution of gold process.



Would this work?


----------



## butcher

Yes gold can be put into solution as described, what Traveller11 is discussing is a basic (opposite of acidic) hypochlorite leaching system used to put gold into solution with some types of (normally pretreated) ore. It is not normally used for materials like electronic scrap, or other metal industrial scrap materials. Where other processes are known to work better.


----------



## jason_recliner

butcher said:


> ...
> Sodium hypochlorite (Bleach) is an alkali solution; the sodium hydroxide NaOH involved in the bleach keeps it caustic enough to keep the chlorine in the solution of water.
> ...


I found this post exciting, because it's the first time I saw someone mention NaOH and that it's actually ok. For ages I've been trying to find out what's in "Chlorox". We don't have it in Australia. So I wanted to compare our "White King", which also has NaOH in it that had been concerning me. (The idea of mixing acid and alkaline sounds like how people hurt themselves.) Now, a search for MSDS gave up about 20 Chlorox bleach products! Would this be the one you guys use? It's "Regular Bleach". http://www.thecloroxcompany.com/downloads/msds/bleach/cloroxregularbleach0809_.pdf

White King has 42g/l sodium hypochlorite: available chlorine 4% when packed, with an estimate of dropping to 2% available chlorine by the Use By date. It also has 9g/l sodium hydroxide. So it sounds similar. What's written on your Chlorox bottles?

Also, and just thinking out loud here, it makes sense to me to keep a not too tight lid on the HCl/NaOCl combo, in that you would need less HCl overall. By my reckoning, a gaseous chlorine jar-cloud should help keep more Cl in solution longer than if it were open to the air. So since the Cl evaporates but the NaOH doesn't, you'd eventually run out of the total amount of bleach you can put in, even small amounts at a time, before the acid becomes neutralised and you need more acid. Correct me if I have it wrong.

[Edit: By "not too tight lid", I meant the first bite or so of the thread; the lid still rattling around. Just to keep the chlorine gas _concentration_ up but definitely no _pressure_ build-up. Perhaps "loose fitting cling wrap" would be a suitable choice.]


----------



## Evan2468WDWA

butcher said:


> Yes gold can be put into solution as described, what Traveller11 is discussing is a basic (opposite of acidic) hypochlorite leaching system used to put gold into solution with some types of (normally pretreated) ore. It is not normally used for materials like electronic scrap, or other metal industrial scrap materials. Where other processes are known to work better.


Thanks for the information.


----------



## butcher

Someone else here on the forum can explain this better than I can, I am not so good at putting thoughts to words, and often say things backwards from the way I think, and here I may have added thoughts on two processes somewhat together to try and get these thoughts across...

Normally on the forum in the process where we use HCl acid with our fine gold powders or foils we add plenty of acid for the amount of gold, an excess HCl will not be a problem, and excess acid is actually more desirable than not having enough, for several reasons (one is to stay acidic), we also add just a little bleach at a time in small proportions, adding (the about a 3% to 6% solution of sodium hypochlorite NaClO), the normal household bleach used to wash your clothes, not the new lemon smelly types or some other fancy kind, (the Clorox is one name brand bleach), or sodium hypochlorite, the sodium hypochlorite is added in small proportions at a time to keep chlorine forming in solution and reacting with our gold (allowing reaction time in between additions with keeping temperature in mind), until the gold is dissolved.
Here we need to be careful not too add too much NaClO bleach, for several reasons, besides just wasting our money on chemicals, we dilute the solution, we lower the pH, making salt NaCl out of our acid, we can have excess chlorine (or hypochlorite if we go too basic) which can make recovery of the gold more difficult later, or until we remove the excess chlorine from solution before the precipitation stage, ( or if made basic we acidify to convert excess HOCl to chlorine, and then drive off the dissolved excess chlorine gas from solution) usually done with sunlight and time, or slightly heating the solution…

Just a note: heat will drive off gases; dissolved gases stay easier in a cold solution than a hot one. Pressure can also hold gases in a cold solution easier, but can become very dangerous, pressurizing a solution can also increase the temperature, or lower the boiling point of the solution, pressure and heat can force out gases easier (or more deeply, for lack of a better word here), and actually push more dissolved gases out of solution further, than the same solution at a lower pressure and temperature.
But here we are working with acids or dangerous solutions, where adding pressure to the equation can easily get us hurt if we do not understand the process or how it would be done properly and safely.

As a boiler man, I can safely heat water to drive out more oxygen from water under pressure, in a pressurized heated vessel (with all of the safety’s included in this pressurized vessel), and understanding the principles involved in the thermodynamic reactions.
But with acids an these chemical reactions taking place, and the gases that form here in these reactions, there is no way I would try this in my lab, without a whole lot more understanding of how to do it safely, and understanding what type of vessel, an understanding of what type of safety devices would be needed, understanding of the temperature pressure relationship of the acid solutions, and of the gases that were produced... 
Basically I have just enough knowledge to keep myself out of danger here and know I should not try it, and I also know, or understand that there is no reason to try it anyway...


In this process the HCl acid and sodium hypochlorite form chlorine gas in solution, which becomes the oxidizer for our gold, taking electrons from the gold atom, which then the gold ions can form a bond with the reduced acid and chlorine (chlorides) to put the gold into an ionic solution or dissolved salt of gold chloride dissolved in solution (along with NaCl) normally still in excess of HCl acid ad water (we arent considiring other possible base metals here)...

Normally there is no reason to try and pressurize this, as HCl and sodium hypochlorite are cheap, adding pressure to this equation can also create many dangers, especially if it was not done properly, with proper equipment and a very good understanding of pressurizing vessels, or acidic compounds or chemicals reacting in solution trying to off gas from these reactions which can create dangerous pressures, there are many factors involved also like the thermodynamics, temperature pressure relationship...
Basically it is just Too Dangerous. No reason. Not much added benefit, especially when weighed against the dangers involved…

Warmer solutions are more reactive and will dissolve gold easier or faster, than a slower cold reaction will, a double edged sword here, the warmer solution can also drive chlorine from solution faster or make it harder to keep chlorine in solution long enough to react with the gold, a cold solution is slower but can hold chlorine in solution longer…
We just learn how to balance this double edged sword.

We can also use this knowledge later after the gold is dissolved to rid the solution of excess chlorine when we may have added a bit more than we needed….

In this method we are working on the acid side to dissolve gold, and want to keep on this acid side.

NaCl brine salt solution used as an electrolytic process (with a membrane cell), is used to make chlorine gas at the anode (the chloride from the NaCl being oxidized at the anode to chlorine gas) the sodium ion can pass the membrane to the cathode side, the water H2O is split to H+ and OH-, the membrane blocks the flow of OH- to the anode side, the hydrogen ions reduced at the cathode form H2 gas or hydrogen gas at the cathode, in the cathode chamber the sodium Na+ and OH- form sodium hydroxide or NaOH salt dissolved in solution.

a very similar type of cell using the same brine salt can be used to make sodium hypochlorite, this cell does not use the membrane like above, the chlorine here is disproportionated to form chloride ions and hypochlorite ions, along with the sodium hydroxide being formed in solution. 

The basic solution is desirable (sodium hydroxide lowering the pH) helps to keep the hypochlorite in the water solution, remember water can be an acid or a base, keeping the water basic (opposite of acidic) helps to keep the hypochlorite from oxidizing to chlorine gas in with the water solution. Or keeps your bleach bleach and not chlorine gas, and salt water ...

When we acidify this sodium hypochlorite we form chlorine gas, (if the solution is basic we form HOCl) in solution to oxidize (means to take electrons) the gold atoms to gold ions in solution, or saying it another way the chlorine takes electrons from the gold atoms leaving them in solution with the reduced HCl acid and reduced chlorine which form chloride ions in solution (reduced mean these gain electrons) this gives us gold chloride in solution.

In this process (dissolving gold powders or flake) on the acid side, we need to remember, both HCL and the sodium hypochlorite are mostly water, (32% HCl is 68% water) and {5% NaClO (sodium hypochlorite) is 95% water}, this is normally not a problem because there is much NaCl which is formed in the reaction process, from the acid HCl when it is neutralized with the basic hydroxide solution, the water helps to keep the NaCl in solution which forms, and the water involved helps to keep the salt dissolved, or from precipitating (unless we evaporate off this water).

Also we see from this reaction of HCl and the sodium hydroxide we add (involved in the hypochlorite, bleach) uses up a portion of our HCl acid, (and the base hydroxide which is part of the bleach) to make this sodium chloride salt. 
With excess HCl acid we can keep on the acidic side, aiding in keeping our gold in solution.

But if we add to much bleach at a time, or too much in general throughout the process, we can get closer and closer to a neutral pH. Or even a neutral salt solution with our dissolved gold (actually making it harder to keep the gold in solution, or out of the precipitating with the NaCl), or we can go over to the basic side of the pH range with our gold chloride solution and where the HOCl becomes our newly formed oxidizer keeping our gold in solution...

___________________________________________________________________________________

This discussion above is different than dissolving gold in a hypochlorite (or basic solution) and adding small portions of HCl acid to dissolve the gold, and HOCl instead of chlorine is the oxidizer...

I did add thoughts of both acidic and basic reactions, (I know for some it may be more confusing but for others it may clear up som confusion).

But in the opposite reaction of dissolving gold in a hypochlorite solution with a little acid addition as discussed for ore, the reactions and chemistry is actually very similar, with very similar principles (almost the same with slight differences) except for the side of the pH scale your working with, and a slight difference in the oxidations states of the chorine, or its compounds, hpochlorite compounds...
Basically both form salts of dissolved gold solution..

It is harder for me to explain the oxidation an reduction of basic solutions, I think backwards enough already, and to look at backwards , backwards, I really get things confused or backwards.


----------



## lazersteve

A side note to this conversation is that you can use hydrogen peroxide and muriatic acid to dissolve gold foils and powders as well. As with bleach add the peroxide in small doses as need with stirring to get the job done. I prefer using 35% hydrogen peroxide, but any strength should work albeit the weaker concentrations of peroxide are slower to react and create larger volumes of waste solution.

Any mixture of chemicals that produces chlorine can dissolve the gold. You could even theoretically use electricity and salt water or straight HCl.

Steve


----------



## jason_recliner

Thanks Butcher and Steve. That's brilliantly useful background information.

Based on what I've picked up over the past three weeks, with credits also to Pantherlikher, Solar Plasma and more, I'm quietly confident my next batch (hopefully I'll find time this weekend) should give much cleaner foils and less "everything less reactive than copper" cement. (Even though I know it'll all refine the same, I wanna my cleaner foils!)

And I've also got proper filters on the way, rather than, *cough*, paper towel.
This is all just slightly addictive...


----------



## FrugalRefiner

jason_recliner said:


> This is all just slightly addictive...


Ohhhh... You poor thing. You still think it's just _slightly_ addictive!  

Dave


----------



## 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

army_greywolf said:


> 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

anachronism said:


> 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

army_greywolf said:


> 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

anachronism said:


> army_greywolf said:
> 
> 
> 
> 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
Click to expand...


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

army_greywolf said:


> 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

anachronism said:


> army_greywolf said:
> 
> 
> 
> 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
Click to expand...


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

nickvc said:


> 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.


----------

