Hcl/cl problem

Ok guys I think I did everything right. Used 60ml of hcl and 20 ml of bleach. Put all that in a beaker along with little under a ounce of pins and a little bit of foils from ram. Left it sit for couple of days. Stirring everyday. Used heat for about a hour reduced to 60ml. Mixed the hcl with hopefully gold in it with 80ml of water with two tablespoons of smb. Been sitting for a couple of days. Tested with stannous and the light brown to dark brown on the cotton swab went to a bright yellow. Why? And what happen to the gold? The smb is now on the bottom if the beaker. What went wrong guys? I know from looking at the pins that the gold is gone but not all the pins. Is there too little gold to bring out or what? Thanks in advance for your help!

Forgot to mention the water was distilled water from the store. Smb is new so is stannous.

It sounds like you dissolved gold then cemented the gold back out of solution onto copper (pins).

You need some more study on how to process.

Remove base metals before you dissolve your gold.

So instead of letting the pins sit in the hcl/cl I should let the solution run over the pins?

No that would not do any good.

We dissolve away base metals (but do not put the gold in solution), the base metal solution is rinsed away from the gold (powders, foils), before we put gold into solution.

Read up some on the reactivity series of metals, Hokes book as you read what she teaches; you will begin to see she removes the base metals before dissolving the gold.

Test your current solution if any sign of gold from the stannous test, (a brown after SMB is most likely a false positive if you used excess SMB), if you see a violet color, the gold can be recovered by cementing on a clean copper buss bar, most of your gold is most likely still with the un-dissolved pins (cemented to that copper remaining from the pins), you can dissolve the copper from those pins in acid peroxide, (caution do not use too strong of Hydrogen peroxide the idea is to dissolve copper not the gold), once you get all of the copper into solution, you should be left with black to brown powder and possibly some gold foils, wash this well before dissolving this gold (especially if any solder was on the pins, using Harold's technique (to get the gold shining) can help tremendously, the powders may contain lead chloride from solder, which is soluble in boiling hot water.

If gold is in solution (the gold is missing electrons),(oxidized), if this solution comes into contact with an elemental metal (having all of its electrons), and the metal higher in the reactivity series of metals (more reactive), this more reactive metal will donate its free electrons (oxidize) to the gold (the gold now having all its electrons will cement out of solution (reduced) as a metal (brown to black powder), and the more reactive metal copper in this case now is missing electrons (oxidized) so it goes into solution as a dissolved salt (Copper chloride in this case).

Ok butcher I see what you mean. My first batch of hcl/cl does have a green color. I do have a dish of hcl/periode I am using for the ram. In the future for pins I'll use the sulfuric acid cell

sounds like you have a plan.

Will muratic acid by itself dissolve base metals? Or do I need to add another chemical. Also what ratios should I use if another chemical is needed?

Sjeepboy said:

Will muratic acid by itself dissolve base metals? Or do I need to add another chemical. Also what ratios should I use if another chemical is needed?

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Very slightly and not very well. Use 3 parts HCl to 1 part 3% hydrogen peroxide(H2O2). Add a bubbler to supply oxygen and low heat to assist the process.

From doing a little reading about the reactivity series of metals, you will find some metals are very reactive (they can react with water) (K, Na, Li, Ca), some metal a little lower on the reactivity list will react with acids, these are above hydrogen in the list (Mg, Al, Zn, Fe, Sn, Pb,) as well as the metals that we listed above), then we also see the metals that can react with oxygen (Cu, Hg, Ag as well as those above), then we see metals that are very nonreactive like gold and platinum group.

also some metals are so reactive (in a certain substance like air or a certain acid that they build a protective layer or passivated layer, this oxidized layer protects the metal from dissolving further with that acid or substance the protective shell of oxidized metal keeps acid or substance from attacking new metal, some metals like iron also build an oxidized shell but like iron the rust layer flakes off or allows acid or air and water to get under this layer and attack more metal.


From this information we see we can dissolve several metals into acid, without using an oxidizer,
we Know that copper will not dissolve in an acid like HCl, but it is reactive to oxygen, and the copper oxide will dissolve in HCl, but we also know if the oxidizer is too strong it can dissolve gold along with the other base metals (which would be a mistake),

So here you see why we may use straight HCl on a material to dissolve the tin from the solder, make the lead a powder of lead chloride (soluble in boiling hot water), and to remove other base metals like aluminum zinc or iron, leaving us copper and gold, which we may choose to dissolve the copper with a copper chloride leach (AKA acid peroxide solution), leaving us gold foils.


Something to add to this is,

While your studying the reactivity series you will notice how a metal higher on the reactivity list will replace another metal lower on the list which is dissolved into solution, example if you have silver dissolved in solution , how adding a piece of copper metal to the solution will cement out silver as a metal powder.

Also if you have metal salts, they can have certain solubility's, knowing these can be very helpful which salt is soluble in water, acid or what substance, how soluble is it (how much will dissolve into this solution), and if the solution needs heat how much more will it dissolve into solution at what temperature, or can we remove a salt from solution by cooling off our solution, this can also be very helpful separating one metal salt from another.

So yes you can dissolve metals in an acid wash alone (depending on what metal or acid we are talking about).

Temperature can also be an important factor in our processes.

So butcher I can dissolve the copper then filter out the gold. And the copper will stay with the solution?

Yes, you can dissolve copper but not the gold, and keep the copper in solution, either filtering, or better yet letting gold settle and decant solution from the gold.

We can do this with nitric acid, nitric acid will not dissolve gold, but will attack copper, the gold would be left as flakes or powders, the copper would be in solution as a copper nitrate solution, (nitric acid dissolves most of the base metals), and they form nitrate solutions of the copper or base metals, nitric acid will also dissolve silver.
Tin (from solder) is a big mess in nitric acid.

Another way we can dissolve copper and not the gold, the gold in flakes foils or powders, the copper as copper chloride solution, is by using the copper chloride leach (acid peroxide leach), using HCl with a small addition of 3% Hydrogen peroxide, a fish tank air pump can be used as a source of oxygen after the initial reaction is started, (instead of adding H2O2 later), this works well for thin copper like gold plated memory finger foils, pins or larger copper it is a slow process but can be done using this method, solder or tin is best kept out of the process (can pre-treat with straight HCl to remove solder), (if solder is involved the lead forms a white precipitant lead chloride powder tin will slightly dissolve into HCl as stannous chloride making filtering a problem), also since we do not want to dissolve gold we do not want to use a more concentrated solution of hydrogen peroxide which could put gold into solution, copper can also form a white powder copper I chloride, if the HCl in the leach is low, adding a little more HCl will put the copper back into solution as copper II chloride, for more details see the general reaction list (in the general chat section) also follow the links provided in the general reaction list, Laser Steve's web site is a great resource to learn from.

Then we also have the concentrated sulfuric cell which can de-plate gold from the copper, here if done properly copper does not dissolve but gold plating is removed from the copper (also found in the general reaction list and Steve's web site).

How long does the process take when using a copper buss bar in auric chloride to drop the gold? Just a general question based on similar experience with same problem? Generally how long should you leave the copper buss bar in solution?

Anarchy618 said:

Generally how long should you leave the copper buss bar in solution?

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Until the solution no longer tests positive for values.

Dave

Is there any way you could post a reference picture of any powdered gold collected after buss bar drop in auric chloride? And when I used this method I ended up having to scrape this stuff off the copper pipes which kinda shelled itself on the pipes & then needed to be crushed up into a dark reddish brown powder. I just want to make sure I did not collect any unnecessary elements. Would you please be kind enough to quickly explain & show a pic? It would be extremely helpful for me.

Is anyone wise enough to know if the picture of my powder looks right?

If that is the cement that came off the solid Copper then it will contain all metals less reactive than Copper with probably a little bit of Copper contamination. Did you clean the Copper before putting it in the solution ?

Usually at this point I would re-refine and drop with SMB to get very pure Gold.

Once you have powder like this to work with, re-refining is very easy, you can easily see as everything goes into solution and it is much easier to not overdo the Nitric acid.

Actually I should have been more detailed in my post. The processes I use are as follows 1st (hcl + peroxide with an air pump line feeding in bubbles for oxygen for at least 5-9 days depending) then for 2nd part (I use hcl + bleach to dissolve) then I'll do an smb drop (using stump out) and/or also use copper to make sure I get it all. To be honest, I really enjoy doing the drops with copper because I like the process off scraping all the cement off after letting the pieces "air dry" and then crushing the flakes up into the powder. I would actually love trying the aqua regia process but haven't had any successful attempts trying to create the nitric acid. I have plant fertilizers, but can't seem to produce the right results. Anyway I digress, most of that powder in my picture resulted from me scraping dried cement off copper & crushing. But there's also different amounts mixed from other smb drops that I've been adding all to what you see in my pic. That being said, what do you think?

I would love & could also use any advice on why I always end up using too much bleach, which always ends in there being NO reaction after dissolving & dropping in smb for precipitation. Nothings more of a bigger bummer than getting to everyone's favorite part and NOT getting a reaction due to high amounts of chlorine that need to be evapped off. So I began using copper after & because of that annoying problem.

One of the advantages of using bleach as your oxidizer instead of nitric acid is that the chlorine from the bleach will dissipate on its own given some time and or heat. Many people leave there solutions for a day before trying to precipitate their gold. Others will heat the solution to drive off the excess chlorine a little faster. Are you allowing enough time before you try to precipitate?

What kind of bleach are you using?

Dave