# Getting gold off gold-filled or the like?



## goldanalog (Aug 12, 2020)

I have an electronic gold tester, an RS Mizar ET18. It has five readings: Non-gold, flash gold, >10K >14K and >18K. Flash gold is the thinest gold plate, and so I'm thinking the others are either thicker gold plate or something like filled gold. I am just taking a guess. I'm talking about costume jewelry Much of the unmarked goldtone kind registers as Flash gold, 10K or better. 

I have some of the >10K now in a container that just has 9 parts 30% vinegar to 1 part sea salt. I will be using a little heat from a hot plate. Just starting out so any advice is welcome. I just want to collect the gold and dry it out and put it in a vial as my first accomplishment.


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## goldanalog (Aug 14, 2020)

I let it sit for 3 days and now there is just silvertone left and no gold flakes. It seems the gold has melted into the liquid. Is there an easy way to precipitate it?


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## goldanalog (Aug 14, 2020)

I asked the first part over in techniques and it didn't get a response after 3 days. Thought I would ask it here. 

I have an electronic gold tester, an RS Mizar ET18. It has five readings: Non-gold, flash gold, >10K >14K and >18K. Flash gold is the thinest gold plate, and so I'm thinking the others are either thicker gold plate or something like filled gold. I am just taking a guess. I'm talking about costume jewelry Much of the unmarked goldtone kind registers as Flash gold, 10K or better.

I have some of the >10K now in a container that just has 9 parts 30% vinegar to 1 part sea salt. I will be using a little heat from a hot plate. Just starting out so any advice is welcome. I just want to collect the gold and dry it out and put it in a vial as my first accomplishment.

I let it sit for 3 days and now there is just silvertone left and no gold flakes. It seems the gold has melted into the liquid. Is there an easy way to precipitate it? I never had to add more heat, it was never heated. 

Also, what kind of protection should I use from the fumes? It's in a large shack type building in my backyard but I notice the smell kind of stays with you for a while.


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## FrugalRefiner (Aug 14, 2020)

Please keep all your posts on a particular subject in the same thread. I've merged your other post into this thread. If you feel your thread would be better in a different section of the forum, just send me a PM and I'll be happy to move it.

There are several ways to reclaim gold from gold filled or gold plate.


You can dissolve the base metals away, leaving the outer gold intact.
You can dissolve the gold from the outside, leaving the base metals more or less intact.
You can dissolve everything, drop the gold from the very dirty solution, then re-refine the gold to clean it up.
At this point, you may have dissolved some of your base metal and/or some of your gold. Your gold may have dissolved, then cemented back out on the base metals. Some of your base metals may have dissolved, then cemented back out on your gold. Maybe a combination.

How much material have you started processing?

Dave


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## goldanalog (Aug 14, 2020)

Thanks.

It was about four cubic inches of jewelry, with the usual bends and hollow spaces.


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## goldanalog (Aug 14, 2020)

What if I just wanted to flake the gold off? I was thinking this was going to be like ram board fingers. Would it have just been doable with a weaker solution vinegar? I notice crunching up the jewelry with a big pliers sometimes does it partially.


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## FrugalRefiner (Aug 14, 2020)

Hmmm... I've never worked by cubic inches. I weigh what I'm going to process. You should probably do the same. It will allow you to calculate your yields.

At this point, you have a classic mess (no offense intended). If it were mine, I would proceed to dissolve everything, then drop whatever gold there may be from the dirty solution. It's not an easy way, but it's a way.

Dave

Edit, this reply was written about the material you already started, not to your new material.

Why do you want to use vinegar?


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## goldanalog (Aug 14, 2020)

FrugalRefiner said:


> Hmmm... I've never worked by cubic inches. I weigh what I'm going to process. You should probably do the same. It will allow you to calculate your yields.
> 
> At this point, you have a classic mess (no offense intended). If it were mine, I would proceed to dissolve everything, then drop whatever gold there may be from the dirty solution. It's not an easy way, but it's a way.
> 
> ...



It is a mess. And, it must be my first whiff of this kind of heavy solution as it seemed to do something 
beyond clear my sinuses. I just got a NaSum M201 face gas mask but haven't set it up yet. 

I'm using vinegar because I didn't want to get too deep into this. I don't have any of the other chemicals around. 

Can the gold be dropped now?

I have a lot more of the material I can add. I also have next to this large jar another one with the same mixture and 3% vinegar.


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## goldanalog (Aug 14, 2020)

Can this material be covered once the process is done, that is, there is no more gold-plate or other metals in the container?


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## FrugalRefiner (Aug 14, 2020)

goldanalog, slow down and take a breath.

Asking so many questions so fast makes it difficult to give you answers.

Put your current mess aside somewhere safe, away from anyone, animals, etc. Cover it loosely so any gasses can escape. Keep it away from any metals as the fumes will quickly corrode them. If you smell fumes, you're damaging your lungs, and endangering those around you. We can't give you a quick answer to all your questions. See Why Can't I Ask a Simple Question and get a Simple Answer?

You need to spend some time studying here. Everything you are asking has been covered here many times. I'll use one example.

You say you are using vinegar because you "didn't want to get too deep into this". But combining vinegar and salt as you've done will create HCl, which you can probably buy cheaper than the vinegar and salt you're using. You'll learn this as you study because it's been discussed many times. I can buy a gallon of 32% HCl at my local Menards hardware store for around $4.00. Then I don't have any unneeded acetate anions in my solution, or any of the acetate salts they will create with the base metals that just complicate the process.

Set your current project aside. Spend a lot of time studying. You will be able to recover your gold unless you throw it away. When you have studied enough, you will understand how to proceed. As Master Kan said, "When you can take the pebble..."

By the way, there is a lot of difference between gold-filled and "the like" and how it is best processed.

Dave


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## goldanalog (Aug 14, 2020)

Thanks, Dave.

Any reason to possibly dilute it with water or something? 

I already used the lesser strength vinegar formula to get some kind of tar gunk off a coin.


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## goldanalog (Aug 14, 2020)

I do recognize the dangers, and really did not want to get even this far. I just have too many other interests and thought this could be easier. (Could it be easier will be my next question). I am an extremely safe person who had 57 has not ever broken a bone, nor had a serious accident. 

I understand about putting this mess aside, but I need to know more about what covering it will do. Cover it with a book? These items were glass vases for plants and although they have a flat even top they don't have lids made for them. So, I want to start studying at the point I'm at right now.


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## goldanalog (Aug 14, 2020)

I don't want you all to have to keep repeating the same things so I understand the point about studying.

To answer part of my own question: 

"For example, when you dilute an acid to make a lower concentration, you never add water to acid, you instead add acid to water. It may seem at first that it shouldn't matter, but adding water to acid creates a hazardous situation, so adding acid to water is safer."

From How to Dilute Acid - Sciencingsciencing.com


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## FrugalRefiner (Aug 14, 2020)

goldanalog said:


> I do recognize the dangers, and really did not want to get even this far. I just have too many other interests and thought this could be easier.


Your other interests are probably easier. Everything we do is hazardous. Dangerous acids, fumes, wastes, etc. Even for an experienced refiner, while it may be "easy", it is never without risk. We try to do our best to minimize those risks by thoroughly understanding what we're doing before we start a process.




> I need to know more about what covering it will do. Cover it with a book? These items were glass vases for plants and although they have a flat even top they don't have lids made for them.


You cover it to keep other junk from getting into the solution, and to keep any living creature from being exposed to it. A loose covering will suffice. A simple example would be to put your containers on a flat, solid surface, safely out of harms way, and put a 5 gallon bucket, upside down, over the top. Put a rock or a brick, or something similar on the bucket so the wind or a critter doesn't knock it over. Do not breath any trapped fumes when you eventually remove the bucket.




> "For example, when you dilute an acid to make a lower concentration, you never add water to acid, you instead add acid to water. It may seem at first that it shouldn't matter, but adding water to acid creates a hazardous situation, so adding acid to water is safer."



That is a good rule of thumb. Do you understand why? Not trying to be a jerk here, but it's good to know why these "rules" exist. It allows us to apply them when appropriate.

The prime example is sulfuric acid. When concentrated sulfuric acid is added to water, it creates a LOT of heat. This can create a localized boiling action in the water where the acid is being added. This boiling can expel very hot, quite concentrated sulfuric acid onto you which can absolutely ruin your day, if not your life.

In the case of the mix you have, you have a somewhat dilute solution of acetic acid and hydrochloric acid. Adding water to it, while it may generate heat, will not be so vigorous as to boil and create the hazard mentioned above.

The question would be why add water. There is no need in your current situation. Cover it loosely, as it is, store it in a safe place where the fumes will not affect anything around it, and it will be fine.

Dave


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## goldanalog (Aug 14, 2020)

Thanks for all your help.

A little more background. I've watched about 15 videos of these subjects in the last two months.

My dad was an amateur experimental metallurgist who had a huge lab in our basement. His hobby was trying to find a potable metal, one you could just mix without heat, and he worked at it for at least 35 years.

My brother has a masters in chemistry and just talked to him but I still need your help.

I realize eventually I'll need a precipitate chemical. I think eventually I will add more gold bearing metals to the glass container. Any reason to not do it soon?  What should I know before I get that that next step? Am I making the solution less dangerous the more cosmetic jewelry I add? 

If I made the solution less strong and waited, the gold would not have dissolved into the hcl and I would have had what I was looking for (a vial of gold flakes/dust) if I just washed it with water?


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## Shark (Aug 14, 2020)

While it can work, the use of vinegar is of primary interest for those who can not access better chemicals for refining. It is not easier, better or quicker or even safer than other methods. It still makes hazardous wastes. And can even be more dangerous to use because many people think, "it's vinegar how bad can it be?" In my experience it is more complicated to use than true AR (hydrochloric acid and nitric acid), more complicated than poormans AR (hydrochloric acid and a nitrate salt), more complicated than AP and way more complicated than straight nitric acid. I do a fair bit of gold filled and often use poormans nitric acid in that I use distilled water with a nitrate salt and sulfuric acid for removing base metals (you need at least a basic understanding of how much of each to use). Even the use of AP, (copper II chloride) will remove the base metals pretty well given time. Each method will do the job, but each require a different process to work right. Each is more complicated than I have made it sound and each method can pose greatly different problems when things go wrong. I won't be much help with using vinegar as I only tried once and had such a headache I never tried it again. But I did learn about these others and I am more than happy I did. I can now work gold from many forms, I can do some silver in various ways, and learned so much more along the way. 

Pay attention to Frugalrefiners words, he will not lead you wrong. He (and many others) was here helping others when I started.


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## nickvc (Aug 15, 2020)

I will try to give you some things to think about.
There are easy ways to recover the values from many types of scrap materials but most include the use of toxic, hazardous or potentially lethal chemicals. Unless you know and understand all the steps and potential dangers in the processes and any problems that you may encounter you will be back in the same situation you have now.
Hydrochloric acid on its own will not dissolve gold it needs some form of oxidizer but it will dissolve some base metals, that’s not a completely true statement but for where you are now it’s good enough.
If you have base metals still undissolved then the chances are fairly high that you have no gold in solution to precipitate, do you know how to test your solution to see if you have any gold in solution?
The recovery processes are the most difficult to master but are by far the most important ones, you can teach people to refine gold and silver very easily.
There are no quick answers or ways to learn this hobby, it takes time, lots of reading and understanding what you have read.
Here on the forum you will find all you need to know for free, you just have to dedicate the time to research and read everything relating to the processes you intend to use.


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## goldanalog (Aug 15, 2020)

Thanks for all replies. I'm a rare book dealer among other things and science is something I appreciate but I've only had formal computer programming training. I understand what you're all saying. I realize with some people you really have to belabor these points. 

I did invest $40 in the gas mask. It was nice to be around the chemicals and not smell anything. 

As I mentioned, I have an electronic gold tester and the materials I put in tested for >10K. I know the thing works. It's obvious when it tests for something as gold. How much gold, I don't know. I really did not even want to be around the solution after it started to smell, so I didn't observe it that closely yet. What I saw seemed to be all the gold stripped away and a base silver metal on everything but I did see one gold object. In my imagination, I am thinking, maybe it precipitated already. Perhaps that was just something of more solid
gold than the other plated items. 

I have some nice white hard plastic one gallon containers. They are the kind that almond milk comes in. If I was to store the solution in that with some air space of about 2 inches would that be safe?


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## galenrog (Aug 15, 2020)

What does your $40 gas mask filter? What concentrations? Most inexpensive gas masks are useless against the vapors created in precious metal recovery and refining, which is why many use a well designed fume cabinet. 

My first piece of advice for learning is to read C M Hoke’s “Refining Precious Metal Wastes”. Published over 70 years ago, primarily for processors of jewelers wastes, it is still the best primer on the subject available. Downloadable copies are available within the signature line of Frugalrefiner.

Read it. Read it again. Read it, making real notes on real paper. Write down any and all questions you have regarding terminology and procedures you have while reading. While the terminology has remained relatively unchanged, many procedures, especially those regarding safety, have changed considerably.

By the time you get through it a third time, you may be ready to attempt the experiments described. Before doing so, please return to the Forum and describe, in detail, any questions and concerns you have. Please also describe how you propose to perform the acquaintance experiments.

Time for more coffee.


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## goldanalog (Aug 15, 2020)

While I greatly respect this gold refining hobby/industry, I do too many things right now that take away my time (writing/arts related to spirituality). I like the character growth that comes from handling dangerous chemicals safely, but I feel it comes back to money, and right now I'm not doing this for the money. 

I am mostly interested right now in cleaning up the "mess." I don't want to leave it as is. I have to work out in this storage shack and I don't want a chance of it knocking over. Preferably, I would like to bottle it if it would stay inert in that form. I could always use the HCL in some form down the road. I don't think there is $20 worth of gold there. 

Since the concern is safety, I hope we can turn the conversation more to what to do now as far as if it can be bottled.


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## FrugalRefiner (Aug 15, 2020)

When in doubt, cement it out.

First, test your solution with stannous chloride to see if there is any gold in solution. Don't just test the solution at the top. Give it a good stir before extracting your sample to test. If there is any gold in solution, cement it out with copper. When the solution tests barren, siphon it off and treat it (responsibly) as waste. Put the remaining solids (where any of your gold may be) in an appropriately sized container and store it safely.

When you're ready, your gold will still be there.

Dave


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## goldanalog (Aug 15, 2020)

Thanks. The only sources of copper I have readily available I believe are pre-1982 pennies (that contain some zinc) and coat hangers. Will either of those two work?


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## FrugalRefiner (Aug 15, 2020)

FrugalRefiner said:


> *First, test your solution with stannous chloride to see if there is any gold in solution.*



You don't need any copper if there's no gold in solution. You're getting ahead of yourself worrying about what to use to cement until you determine if there are any values in solution.

Test your solution. Post a picture of your test result.

Dave


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## goldanalog (Aug 15, 2020)

FrugalRefiner said:


> FrugalRefiner said:
> 
> 
> > *First, test your solution with stannous chloride to see if there is any gold in solution.*
> ...



I do not have any stannous chloride. Anything else around the house might work? Since I know about 7 objects tested for gold that I put in there, there must be some in there. The yellow object I saw was a gemstone which I forgot to remove.


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## butcher (Aug 15, 2020)

10% H2SO4 and iron (transformer or motor laminates are a good source of iron), dissolve the iron with heat, corning dish on a solid burner electric hot plate or similar, evaporate to crystalize the green iron salts, you can store crystals in some of the concentrated solution keeping the crystals wet in the acidic solution in a small HDPE bottle with an airtight plastic lid.

A crystal of the copperas (ferrous sulfate) FeSO4 in a white porcelain spot plate (plastic spoon) will precipitate any gold (if involved) from a few drops of the solution forming a brown ring around the crystal...

If PGM metals are suspected the solution from this test can be moved to another well of the spot plate and tested again using an appropriate reagent, now the gold removed from this test will not interfere with this test altering the color...

Tin from solder and HCl making stannous chloride is simple, tin fishing sinkers, tin from pewter, electronic scrap...


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## goldanalog (Aug 16, 2020)

I think I may add more gold items to it to make sure the cementing process is reasonable. It sounds like you are saying even 2 lbs of gold plated items might not register as having any gold content. A lot of items that look like gold register as flash gold, and I'm not even putting that stuff in. 

I would like to do it with stanneous cloride as I don't want to add anything that might bring in another reaction. But that means ordering it from Amazon and waiting a few days. I doubt I have any pure tin in my possession that I know of in. Making pure tin from other objects seems involved. I would like to take out that step and make this as safe as possible. For the copper, I'm just going to get some copper plumbing down at the hardware store. 

Thanks again for all the help. I know I'll need more. Whatever is cemented I assume will be inert enough to keep in a glass vial. Then I believe more processes are involved if I want to get a gold bead.


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## goldanalog (Aug 16, 2020)

Are pre-1982 copper pennies OK? They are 5% zinc. Or is something larger preferred?


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## Shark (Aug 16, 2020)

Scrap copper wire will do in a pinch. Better yet a piece of copper water pipe, slit open and hammered flat. For the amount of gold you possibly have the pennies might work, but I know, first hand, the water pipe works very well when flattened out. If not split open you risk some gold being stuck inside the round pipe.


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## g_axelsson (Aug 17, 2020)

Forget about testing or precipitating gold right now. Acetic acid and salt will create a weak hydrochloric acid. It will not dissolve gold in any reasonable settings. Any gold present will be in the solids. The reason you see white metallic surfaces where it was gold colored before is because of two reasons.

1. It wasn't gold in the first place and the acid removed or bleached the golden paint.

2. Some metals can go in solution at first and then plate out on top of the gold, giving the appearance that the gold went into solution. Different metals and alloys in acid is creating local batteries that can supply the electrical current needed to plate another metal onto gold.

So for now, either abandon the plans of recovery and refining gold, or do some solid learning and research here on the forum. Read Hoke, you need it.

Gold refining is an area where a little knowledge can be dangerous. A few youtube videos is not a solid knowledge base to stand on.
Also, prepare to pay more in chemicals and equipment than any gold you will recover over in the near future. This can be a profitable hobby or even a career, but it will take time and effort. If it was easy everyone would do it.

Göran


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## goldanalog (Aug 17, 2020)

Excellent. I needed to read everyone's post. And I have started to read Hoke. The last post was especially interesting as you are saying that the gold that I put in and tested as gold is still on the items? Is there any way to return it to the bright yellow color? I have no reason to disbelieve my electronic tester.

One possibility is that even though it registered as a grade above "flash gold," it's still relatively thin and washed away as if it were paint. 

I am going to use my long tongs and take one or two of the items out and examine them away from the container. Any suggestions on what I should be looking for or do? 

I am the type who likes to learn by doing, but I wouldn't have gotten in this mess if I knew anything when I started. People should make comments on these YT videos about how dangerous the vinegar method can be.


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## goldanalog (Aug 17, 2020)

Today I poured off a large amount into a gallon plastic jug that was half filled with water. I'm hoping this dilution is OK. I capped the jug with its original screw cap. 

I switched lids on the main mixture to an old silver-plated serving tray that is perfectly flat because I noticed the lid I had on it before had a slight curve to it. Hoping this introducing this metal doesn't do anything bad. 

I will probably fish out one of the pieces of jewelry, put it in some water to get the acid off, and have a crack at it (literally) with some pliers to see what's going on. I might retest it for gold.

I have the day job to do (in this case painting my house) so I was only able to find the pennies or a copper hanger, and didn't have the time to start tearing apart some broken electronics for some copper. Since I didn't get an OK on either, I didn't proceed with that. Sometimes about coat hangers doesn't seem like 100% pure copper.


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## goldanalog (Aug 24, 2020)

I'm hoping I can get a direct response to this question  

I left half the liquid in the container with the precious jewels.  

I really need to work around this area, so would like to pour the remaining liquid directly into a gallon white plastic jug and then cap it. I want to do some more work with it later. It seems like the plastic is strong as far as these kinds of containers go. I am wondering if this will be OK. Obviously, the solution doesn't seem to be omitting too much gas or it would have blown the lid off, although I imagine if I take the lid off there might be a little compression and more fumes might come off immediately. 

My question is, is that OK and safe?


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## FrugalRefiner (Aug 24, 2020)

What kind of plastic jug? Look at the code on the bottom of the jug and let us know.

Dave


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## goldanalog (Aug 24, 2020)

FrugalRefiner said:


> What kind of plastic jug? Look at the code on the bottom of the jug and let us know.
> 
> Dave



It says HDPE with a 2 in the symbol for recycle.

I did a search on "can you store hcl in 2 hdpe" and got a chemistry.stackexchange response that says you can. Let me know if there is still a problem because of the metals that have been soaking in it for 2 weeks. 

The funny thing is the lid was the problem as its one of those that can get tight but then goes through cycles where it will get lose again. I guess having the foil seal avoided that problem before it was open but its not a good type lid for acids. Luckily it only had a little water in it when I was reading the bottom as it dripped out even when tightened. Spoiled milk makes you go back to the store for more. 

I found a HDPE 2 jug from laundry detergent and I'll use that.


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## FrugalRefiner (Aug 24, 2020)

HDPE will be fine.

Dave


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## goldanalog (Sep 23, 2020)

I let the jewelry sit in some water and that further purified it by rusting out any ferrous elements. I didn't want to test it again because the tester has a liquid dipping reservoir and the items have to be perfectly clean. Just posting as I didn't forget to let you know my progress.

The rusting technique made me think there might be an interesting safe technique created in the future of removing ferrous materials that way. Just to get it a little purer. A vise, some water, hammer, and a "gold brick" made from plated material?


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## Palladium (Sep 23, 2020)

Rust is only a passivization of the surface material to protect the underlying materials. Somewhat like silver chloride crust will stop the dissolution of the gold underneath it.
It does not work as a way to remove large volumes of base metals from materials to be refined sir.


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## nickton (Dec 19, 2020)

I wish I lived near that Menard's that sells a gallon of muriatic acid for $4.00. Around here it's more like $8 to $12 a gallon. But since you're going to the hardware store to get copper piping, why not get some muriatic (also known as HCl), and some Bonide stump remover? Or just make your own Copperas, following Butcher's method? 
Where did you get the metal detector device? That's a fairly advanced and costly item at your level I would think.

Keep reading until it stops confusing you. At first it will probably make you want to fall asleep, but eventually you'll begin to remember and recognize key concepts. I had to read and re read Hoke's book before I could correctly start connecting the dots at all. 

Become familiar with the reactivity table to understand "cementing". 

If you have lab glassware of any sort, it will be a godsend. I had no intentions at first of getting one, but I eventually found a distilling apparatus to be particularly helpful, and heating equipment is necessary. You simply must have basic tools to do this safely, and I'm not talking about a respirator. Do any chemical reactions outside, unless you have a fume hood. ETC...

I hope that didn't come off as rude. I'm not sure what you know yet.


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