chlorox on incinerated flatpacks

Refering to the thread: http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=52&t=11827&start=280 (Gold inside chips (black, flatpacks - not CPU)

I learned how easy aqua regia is, when you only use the amount nitric that is actually needed. Well, Harold says, there is no reason to use aqua regia for recovery, but only for refining. I also learned how easy chlorox-method is, when you can see the gold dissolving, adding just enough chlorox to dissolve.

Now to my question. Since I can't find data about amount chlorox per gramm gold, - probably because it absolutely depends on the conditions and it cannot be definated generally, I wonder how to guess, how often I will have to add a small amount of chlorox to my well-prepared basemetalfree incinerated flatpack batch? Sure it depends on temperature, maybe even pressure and humidity, but how do you guess how much, when you can't see the gold, only knowing, there is 1-3 g in that pound of powder? Aqua regia seems almost to be easier, since there it will be round about 1ml nitric per gramm of gold.

I don't need a correct number, only a guess that is more qualified, than mine.

In Lazersteve's advice the gold has to be visible. That's just my problem.

Lazersteve

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.

Click to expand...

the sodium hypochlorite is converted by the hcl into chlorine gas and sodium chloride.you really cant add too much bleach (stop adding when gold is dissolved) as the chlorine (being a gas) will evaporate out of solution on its own given enough time. fluids will hold more gas in a cool state and expels gas faster in a heated state, so heating will make the excess chlorine "gas off" faster.you will be left with your solution plus the added salt from the sodium hypochlorite. the salt (being water soluble) isnt a problem when cleaning up your gold powder.

Thank you, Geo!

Well I really don't recommend skipping over base metals removal; because it really helps avoiding later possibly occurring problems.

As said before aqua regia should be really used to refine and/or a last stage of recovery.

2HCl + NaOCl → H2O + NaCl + Cl2
So Cl2 has to oxidize the gold and also take chorines to create HAuCl4
→ 4HCl + 2NaOCl → 2H2O + 2NaCl + 4Cl2
meaning 4 (Cl2) molecules per Au atom. (2Cl2 to oxidize and 2Cl2 to form HAuCl4)
→→ 4HCl + 2NaOCl + Au → HAuCl4 + H2O + 2NaCl + 2Cl2 + H2 → HAuCl4 + H2O + 2NaCl + Cl2 + 2HCl
a mix between these 2 will result:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ → HAuCl4 + H2O + 2NaCl + 2Cl2 + H2

(note that the underlined part of the formula is not balanced; this is because it will change the main formula and this is not necessary since the main goal is achieved so it doesn't matter what the resulting byproducts are)

Au / 1 mole / 197g/m / 100g
NaOCl / 2 moles / 74.5g/m / 75.6g
HCl / 4 moles / 36.5g/m / 74.1g

Depending on the concentration of the Clorox you are using,
you can use this formula to drive it;
75.6g~~~252ml // 74.1g~~~247ml
------ x ------ //// ------ x ------
100%~~~30% //~~~100%~~~30%

To dissolve 100g of Au you will need 252ml of NaOCl (Clorox) @30% and 247ml HCl @30%

Solar,

Your question has been raised numerous times in the past. Below are some of the highlights of the discussions. You can read the associated threads that the links are found in for more tidbits of information as well.

The chart in the link below defines the dissolution rates of gold for various etchants.

Gold Etchant Rate Chart

and the equations for various gold etchants:

Gold Reaction Equations

using the chart you can theoretically calculate the amount of gold that would be dissolved based upon time and temperature.

As for the maximum amount of gold that HCl-Cl can hold at a theoretical maximum:

HCl Gold Saturation

and finally a few chlorine solubility charts:

Chlorine Solubility Charts

From the dissolution, solubility, and saturation data we could calculate the theoretical amount of bleach (at a given concentration and temperature) that is required to dissolve a given amount of gold into a given amount of HCl. I'll leave that math up to you. For all practical purposes, add only enough Clorox to get the gold dissolved, any excess (as Geo stated) simply generates chlorine that goes up into the atmosphere and chokes everyone around you.

Steve

Thank you all! Sorry, I didn't find it by myself, I feel, that sometimes searching all the posts, I stand directly in front of the answers I am searching and do not see, I have found them. Maybe your three answers would be some stuff for the forum handbook III.

Solar,

I'm always happy to help those that are helping themselves, much like you are. One key to finding what you are looking for on the forum is know what to look for. Here's a quick blurb that applies to all member posts on using keywords in posts:

Keywords in Posts Help with Searching

and my search methods from the Guided Tour:

Successful Searching

The forum Reaction List and Guided Tour threads are constantly evolving, I typically edit them once a month or more depending on valuable tidbits that turn up during everyone's day to day discussions.

The biggest problem with handbooks is that they are snapshots of forum posts and they don't capture updates that are being made everyday to the material that was copied. As an example of what I'm referring to check out the Reaction list as it appears on the forum today compared to the way it looked back when the 'Forum Handbook II' was captured a few years back. The two are very different. For this reason I always recommend that members refer to the source of the information, not to a facsimile or snapshot of the way the information was originally presented. In a every changing and evolving refining environment, it benefits us all to use the latest and greatest information. That is the real power of the forum, it's that the community grows together. This is also the downfall of information that was originally taken from the forum and repeated elsewhere. These 'external' sources do not benefit from the contributions of the community; therefore, they are only as good as the last 'copy'.

The same is true of the numerous gold calculators, yield data, and other spreadsheets. They only reflect one version of the information, for these I suggest everyone learn how to make your own calculations and find your own yield data. The other problem with gold calculators is that they do not account for normal losses associated with the recovery and refining processes. Yield data greatly depends on the skill of the refiner making the table. An accurate, detailed lab book is a powerful tool in your refining toolbox.

Steve