# Hydrochloric acid 10%



## TXWolfie (Sep 23, 2011)

I recently found that I had a bottle of pool water testing drops. Its a full bottle .75oz the Hydro acid is 10% with Orthotolidine @ 1%. Can I use this to make gold testing liquid. Before the answers fly to just buy the acid, like I have said in a few recent posts money is tight and I was just curious if I could use this to make stannous. Be gentle guys I await the flaming ... lol


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## jimdoc (Sep 23, 2011)

I wouldn't use it. For testing you want to know that it is right.
Muriatic acid is very cheap, check Home Depot, Lowes or Ace Hardware.
You will need it in your refining anyway.

Jim


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## TXWolfie (Sep 23, 2011)

Ok will just hang out and wait till I get some funds for my hobby ... thanx for the answer


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## jimdoc (Sep 23, 2011)

Try a wanted post on Craigslist.
Just say that you are looking for some left over muriatic acid to clean your concrete.
Then mention that the fumes will corrode everything around, or the dangers if the kids find it, so you may get some people who want to get it out of their garage.

Jim


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## TXWolfie (Sep 23, 2011)

omg...lmao thats funny


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## Geo (Sep 23, 2011)

TXWolfie
for your own benefit, it would probably be best to refrain from using texting lingo on the forum. if Harold sees it he will bust your chops over it. you may want to edit it out or spell it out.


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## Claudie (Sep 24, 2011)

I think HCL is about $5.00 a gallon around here. Home Depot is where I get mine.


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## rewalston (Sep 24, 2011)

Here in Ontario (Newmarket to be precise) Home Depot quit selling HCl. I got mine at Home Hardware it was, I believe, $9 and some change. 

Rusty


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## Harold_V (Sep 24, 2011)

Geo said:


> TXWolfie
> for your own benefit, it would probably be best to refrain from using texting lingo on the forum. if Harold sees it he will bust your chops over it. you may want to edit it out or spell it out.


True! I don't tolerate any of the shorthand lingo that can confuse. In fact, if a reader posts a question and doesn't use acceptable language, I won't respond to him, even when I have the answer. We expect readers, here, to use manners, to use proper text, and to refrain from foul language. 

I'm not overly concerned about his message in this instance, because it pertains to nothing of importance. However, it does encourage the use of jargon I do not find acceptable. I get pretty damned ornery when that happens. 

Harold


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## Nickpearl (Oct 30, 2011)

Hi all,
Some questions:

I can purchase HCL 50% reasonable. Does 50% versus 31% Muriatic change the AR ratio?

I tried making Stannous. It turned deep yellow (with much tin left on the bottom) and testing the solutions told me nothing (perhaps it was a short between the headsets here.....). Any experiments I can run as I try again to formulate the solution?

Lastly, Harold, where can I find watch covers? I see Corning sells them for a first born plus all future revenues. I got a bit worried about losing gold with all the HCL washes on my powders. I also ordered new beakers and wish to try boiling (need a hotter hot plate) instead of all the stirring (glass rods) I've been doing.

Thanks,
Nick


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## goldsilverpro (Oct 30, 2011)

Nickpearl said:


> Hi all,
> Some questions:
> 
> I can purchase HCL 50% reasonable. Does 50% versus 31% Muriatic change the AR ratio?
> ...


All the 50% HCl I see for sale is marked as 50% (v/v). This means 50%, by volume, of concentrated HCl. About the strongest HCl you will find for normal lab use is about 37%-38% (w/w = by weight) - this strength is called concentrated HCl. One liter of 50% (v/v) is made from 500ml of about 37% (w/w) and 500 ml of water. Therefore, the 50% (v/v) is only about 18% (w/w). 

(1) 37% HCl (w/w) contains about 438 g/l of HCl
(2) Muriatic acid of 31% (w/w) contains about 358 g/l of HCl
(3) 50% (v/v) contains about 196 g/l of HCl

I would suggest using muriatic acid for AR. It's the cheapest and it works quite well. The 37% (w/w) would go a little faster, but it is more fumey and more expensive. The 50% (v/v) would go slower and you would end up needing nearly twice as much.

Another consideration. On the forum, the AR, AP, and other processes using HCl are usually based on the use of muriatic acid.

--------

Watch glasses are available, inexpensively, from about any lab supply. A small lab supply is more likely to sell them individually, rather than having to buy a dozen. They are available in about any size. I usually had different sizes of watch glasses for the different sizes of beakers. In very loose general terms, I preferred a watch glass that was about 1" larger in diameter than the diameter of the beaker I was using. Although you can use a huge 8" (200 mm) watch glass on a small 2" diameter beaker, it is awkward and much more prone to accidents. Best to get the right sizes. Three types of glass watch glasses are generally available - thin, thick (heavy duty), or ribbed. The ribbed ones raise the watch glass a bit to allow gases to escape and thus prevent the watch glass from rattling around, especially when boiling. However, most beakers have a pour spout and gases escape through there. 

When I didn't have a watch glass, I used a small kitchen plate or saucer, which are of a similar shape. The problem is that the sizes are greatly limited, as compared with watch glasses. Some of these are porous and some are not acid resistant, so you have to be picky. I found the Corelle ones to be about the best. They are made of smooth tempered glass, they are very chemical resistant, and I like their shape. They are cheap and I've seen a lot of them in flea markets.


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## niteliteone (Oct 30, 2011)

I have found 2 stores that sell varions sizes of watch glass's at a reasonable price.
http://www.avogadro-lab-supply.com/category.php?category_id=79

http://unitednuclear.com/index.php?main_page=product_info&cPath=25_72&products_id=320

Just check the shipping charges as they can be as much as the product. :shock: 

Tom C.


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## Nickpearl (Oct 30, 2011)

Thanks for your prompt responses, both of you, goldsilverpro and niteliteone. Much appreciated.

Here's an interesting event I observed (ok, I must have caused it). I readied nitric'd gold fill for AR. After rinses and filter, I was ready to drop. I had used way too much water I think, couldn't remove fine whitish sediment, so when I did drop it, nothing happened. I recalled some others using Oxylic Acid so I did that (a bit desperate, I guess). Now I have powder on the bottom and a gold plated beaker. 
I somehow did this before, earlier this summer, and with all safety precautions, mixed some AR and held it on the sides of that beaker until the plating dissolved.
Any ideas of what I did?
Again, thanks.


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## Harold_V (Oct 31, 2011)

Nickpearl said:


> Any ideas of what I did?


I could be wrong, but I'm of the opinion that what you did was work with dirty vessels. Don't be afraid to wash your glassware well. Very well, indeed!

How dilute your solution is won't make any difference where precipitation is concerned. Gold is unlike the platinum group in that it will precipitate from _very _dilute solutions, and do so so completely that none can be detected in solution. For all practical purposes, a 100% recovery. 

Harold


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## Geo (Oct 31, 2011)

i have a coffee pot,just one in particular that the gold precipitates onto the sides and sticks.ive washed it in everything i can think of.i dont want to just toss it but if i cant figure out why its doing this i will have to.


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## Harold_V (Nov 1, 2011)

Geo said:


> i have a coffee pot,just one in particular that the gold precipitates onto the sides and sticks.ive washed it in everything i can think of.i dont want to just toss it but if i cant figure out why its doing this i will have to.


Probably lightly etched, or it has a metallic deposit that doesn't wash off. I'd try a cleaning with hot AR before pitching, or demoting to use only for preliminary processing, never for precipitation. 

Scratches in glassware are notorious for accumulating gold deposits that don't like to release. For that reason, I used only pristine beakers when precipitating, and moved them on to general use as need demanded. A new one replaced the one demoted, so I always had pristine beakers for precipitation. 

To avoid scratching, use a plastic policeman to clean up gold from the sides of vessels after precipitation. Glass on glass is not a good idea.

Harold


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## kadriver (Nov 1, 2011)

Harold_V said:


> To avoid scratching, use a plastic policeman to clean up gold from the sides of vessels after precipitation. Glass on glass is not a good idea.
> 
> Harold



I have two heavy walled 2000 ml beakers that I have assigned as precipitastion beakers only. They are both new or nearly new with no scratches that can be seen.

In the past I would use a glass stirring rod to clean the gold that sticks to the side of the precipitation beaker.

I kind of knew that scraping the side of the beaker with a glass rod would eventually start to scratch the sides of the beaker. So I began using a squirt bottle to forcefully rinse the sides instead of using a glass rod.

While filtering the liquid after dropping the gold out, I adjust the nozzle of the squirt bottle to give a solid stream. As I pour the liquid into the filter, I aim the solid stream of water at the gold on the sides of the beaker and forcefully clean it off. It works quite well

Most (but probably not all) of the gold falls to the bottom and is retained in the beaker for further rinsing. Some of it probably stays suspended in the liquid and makes it into the filter.

If I can see gold in the filter flask after passing through the filter, and sometimes very fine particles make it through, then I re-pour the filtered liquid through the same filter paper.

Also, after filtering, I dry the filter paper, fold it up, place in a melting dish, cover it with borax and gently incinerate the filter paper with my torch until it disintigrates. The borax forms a sticky bath that helps keep tiny pieces of paper and ash (with gold on them) from flying out of the dish.

I usually end up with a small bead of gold that I set aside and put in with the next batch to be refined.

After having said all that, I have a question:

Harold, could you please describe this "plastic policeman" you mentioned? I have never seen or heard of them. 

Thank you - kadriver


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## Harold_V (Nov 1, 2011)

kadriver said:


> If I can see gold in the filter flask after passing through the filter, and sometimes very fine particles make it through, then I re-pour the filtered liquid through the same filter paper.


My experience lead me to never use a filter when washing gold. It became clear to me that once washed, the gold was quick to settle, with rare exception. A few moments of idle time, for the gold to accumulate on the bottom and I could pour off the solution without loss. If there was any question, I would pour to a second vessel, where any gold that may get poured off was easily recovered. It was important for me to not lose any in the process, considering I flagged individual batches and had to settle with the customer on the amount recovered. Any losses would have been a reflection on my honesty, or lack thereof. 

Gold that had been twice refined was never suspended. I could pour off solution with reckless abandon without fear of losing anything. It's a very good measure of the purity of the resulting gold, or so it appears. 



> could you please describe this "plastic policeman" you mentioned? I have never seen or heard of them.


No problem. Here's a link that will make it easy.

http://www.taylorscientific.com/taylorscientific/Plastic-Policeman-Polypropylene-Nalgene-P3047C570.aspx

Harold


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## Geo (Nov 1, 2011)

thanks for the link. good thing you can buy those in singles. :lol:


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## Nickpearl (Nov 6, 2011)

Hi all and great reading. I have yet to buy the Bon Ami, but will. I did get a new shipment of beakers in the mail, that helps. A couple notes:
1. I do use the water bottle and squirt to clear and mist to settle surface stuff.
2. I no longer stir the AR or (how do you say) Auric Chloride - I swirl.
3. I tried to boil by setting my beaker on a Pyrex baking plate on a hot plate with variable controls. Ever hear Pyrex explode? Seems a bit of a crock now that I know about Pyrex. Only then did I study via Google Pyrex and the mistaken notion it can take heat. I did google lab glass (stirring plates, etc.). Wow is it expensive! So now I'll either go by a firebrick or sheet of (not abestos but what the brick store sells) to somehow allow a heating surface on the hot plate.
4. I spilled my filtering set-up full of Auric Chloride and was I bummed! I soaked up as much as I could, put the napkins and some papers it spilled on into a 1000 ml beaker and re-AR'd it. When I filtered to clear liquid this morning, I dropped with SMB. Turned brown immediately and am so happy I at least recovered a bunch of what I spilled. LESSON LEARNED (started with 77 grams of gold filled). 
5. I now have two Buchner funnels and a new shipment of flasks and beakers. Per these posts, will separate for anything AR from all else (Nitric, HCL-H202, etc.)

Since it's getting colder, I am trying to determine what to do for the winter. I can either suspend all operations (use my 2nd floor deck, mostly) or rig up an exhaust system in my front 3-season porch (closed off from the rest of the house during winter). I believe the most important aspect will be venting. Any issues working with this stuff in freezing temps (for moments at a time, of course)?

Thanks again, all....


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