# Zinc... I give up..



## AuMINIMayhem (Aug 5, 2008)

Okay.. I cannot find anything short of "Zinc plated" hardware anywhere locally.. and I realllllly don't feel like ordering Zinc powder online..

I've checked with EVERY lawn and garden place in the area looking for "Moss Off" as I heard this was Zinc powder, but to no avail..

honestly, I'd like to find a good chunk of solid Zinc. I'll take it to my machine shop and shave of a couple 10-thousandths qand use the chips, rather than powder... I think a slower Zinc reaction for precip would give it a chance to drop more values out.. am I wrong?..

any ideas on where I might find any?..

Thanks,
Derek

p.s. will Zinc drop Au out of AuCl? Also, do I need to boil down AR or neutralize with Urea prior to using Zinc? (I know.. the answers are on here, but I have limited access online time-wise.. :roll: )


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## Rag and Bone (Aug 5, 2008)

Get some from lazersteves site. It's very reasonable.


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## AuMINIMayhem (Aug 5, 2008)

Yeah I know. Steve's the man! (I'm just friggin lazy..LOL!)


yeah, I'm just looking for a "quick fix" I have a solution I wanted to precip today or tomorrow at the latest, simply because I'm finishing up moving and don't have the time... once this batch is done, I'm outta the "biz" or well, "hobby" I should say for a while, til I get into a place better suited for this.. so I'll be headin out to the hills on the weekends to go panning..


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## lazersteve (Aug 5, 2008)

For the record, zinc is not listed on my website, but I do have it in stock and will gladly sell some.

Steve


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## Anonymous (Aug 5, 2008)

Electrical conduit connectors are cast zinc.

Jim


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## Rag and Bone (Aug 5, 2008)

I was thinking of tin


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## goldsilverpro (Aug 5, 2008)

U.S. pennies are 97.5% zinc and 2.5% copper coating and they weigh 2.8 grams. You can buy this zinc for $1.66/pound.


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## Anonymous (Aug 5, 2008)

GSP great idea, condiut fitting cost way more.


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## AuMINIMayhem (Aug 6, 2008)

GSP.. is that in the form of an alloy tho?.. hmmm.. now ya got me thinkin.. perhaps I'll break open the piggy bank and throw "my two cents worth" into a small batch.

Thanks..


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## goldsilverpro (Aug 6, 2008)

No alloy. It's copper plated zinc. The copper may cause problems depending on what you're doing.


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## AuMINIMayhem (Aug 6, 2008)

trying to precip Au out of AuCl... should I strip them first?.. deplate? or would a good scrape job with a wire brush attachment on a Dremel do the trick?..

FYI.. at this point I'm only trying to reclaim it out of solution, I'm just trying to clean up right now and don't care about refining it at this point. I'll do that at a later point once I'm in a better location and can take my time to do it properly..(I'm in the process of moving and trying to break down my setup..)

Derek


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## AuMINIMayhem (Aug 6, 2008)

check it out.. a quick google search for "US penny composition" brings me to a "fun facts" section of the US Mint


The composition was pure copper from 1793 to 1837. 

From 1837 to 1857, the cent was made of bronze (95 percent copper, and five percent tin and zinc). 

From 1857, the cent was 88 percent copper and 12 percent nickel, giving the coin a whitish appearance. 

The cent was again bronze (95 percent copper, and five percent tin and zinc) from 1864 to 1962.
(Note: In 1943, the coin's composition was changed to zinc-coated steel. This change was only for the year 1943 and was due to the critical use of copper for the war effort. However, a limited number of copper pennies were minted that year. You can read more about the rare, collectible 1943 copper penny in "What's So Special about the 1943 Copper Penny.") 
In 1962, the cent's tin content, which was quite small, was removed. That made the metal composition of the cent 95 percent copper and 5 percent zinc. 

*The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year. *


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## goldsilverpro (Aug 6, 2008)

I think I would use just copper. The zinc will also drop out the base metals, but copper will only drop out the PMs. Whatever you use, the cementation will stop, or greatly slow down, once the Cu or Zn is covered. You may have to scrape or brush off the cemented gold one or more times.

Why don't you simplify things and just use SMB?


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## AuMINIMayhem (Aug 6, 2008)

The Home Brew shop I get my SMB from is closed for the week.. 

Copper is a great idea, I have access to very pure copper, so I think I'll take that route..  (helps working in the defense industry I have access to very "pure" materials..  )


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## goldsilverpro (Aug 6, 2008)

Here's a little trick to use when cementing. Cementing is, as you know, an exchange mechanism and the metals trade positions. The gold becomes a solid and the copper dissolves. To get this started, you need a little free acid. If you're ever having problems with it cementing, try adding a little fresh acid of the type that the solution is made up from. Doesn't take much. Maybe just a few milliliters.


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## AuMINIMayhem (Aug 6, 2008)

Sweet.. thanks, man!


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## Pawnbroker Bob (Aug 7, 2008)

Go to a local boat or marine/fishing supply. You can buy cast solid zinc anodes for boat motors and hulls. Not really cheap but available. 

Pawnbroker Bob


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## junkelly (Aug 8, 2008)

1983-present pennies are 97.5% zinc and 2.5% copper. That may be good enough for your purposes. If not, the zinc melts at a lower temp than the copper. Heating up a penny will turn the zinc insides molten which can be dripped into water. The copper plated shell will not melt at close to the zinc melting temp. Seems like a lot of effort, but available almost anywhere.

-junkelly


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## Never_Evil (Aug 8, 2008)

If you need to precipitate gold, go to the laundry aisle in walmart or grocery store and get some White out or Yellow out... both contain sodium sulfite and sodium bisulfite. It does work to precipitate gold out of solution.


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## Anonymous (Sep 13, 2008)

Hi all. 300 mesh zinc is available at plans-kits.com/ . 5 bucks for 10 Lbs. I've dealt them before. Fast shipping. It came 40 lbs. in a Priority box. Two boxes of almost hurt my mailbox.


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## lazersteve (Sep 13, 2008)

John,

Welcome to the forum.

What purity is the zinc? I've run into some issues before with zinc that contains a very fine sand like substance as an impurity. The sand substance ends up mixed in with your metals and won't dissolve with the acids normally used in processing the precipitated metals. 

Steve


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## lazersteve (Sep 13, 2008)

John,

The website doesn't have a working link to the ebay store, did you just phone in your order? What's the guys ebay seller ID?

Steve


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## Lou (Sep 13, 2008)

Steve, you *are *the greatest!! Thanks for that comment about the sand, it just made something quite, quite clear to me!!!!!


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## lazersteve (Sep 13, 2008)

Lou,

As you know from our recent PM's I've been struggling to get a handle on the processing of Rh. I've recently found that sand was introduced as an impurity via the zinc flour that was not pure (I even passed it thru a 200 mesh screen before use). I have since switched to a higher purity zinc for my precipitations. Now I'm faced with the task of eliminating the 'sand' from my previous batches. I know HF will do the job, but I think I'll try converting the silicates (?) into a soluble form instead. Since they are so fine, I'm not 100% sure they are silicates, but the residue is something along these lines. I wish I knew how the zinc flour was being produced as that may tell the real story.

This little facet of information has had me baffeled for sometime, but now I know the real truth as to why my yields were higher than expected, and the residues were impervious to the acids I normally use. The 'sand' impurity was the solution (for me anyway). 

I'm glad I could give something back to you Lou for all the help you have provided me ( both privately and publically). :wink: 

Thank you,

Steve


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## Platdigger (Sep 13, 2008)

Wow guys, sorry to hear this, I think I could have been of some help.
I bought some cheap zinc off ebay a long time ago and found this out by just trying to disolve some in hcl that it had a bunch of undisolvables.
Guess I should have brought this up. 
I always figured that I had just bought some real junk.
I would think the thing to always do then, is to just disolve some in hcl to see if it is really just zinc.
Randy


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## lazersteve (Sep 13, 2008)

Randy,

For me I felt pretty foolish when I identified the problem, I should have known better. 

It's just another good example of GIGO. If you put garbage (from any source) into your reactions, the garbage is bound to come out. It also makes crystal clear the importance of knowing exactly what is in all of your reagents before you use them. 

The bad zinc I had was also purchased from ebay. I discovered it was the zinc after noticing that a fine brownish powder in my precipitations would never fully dissolve. After a lot of head scratching I back tracked and tested my zinc and found the culprit.

Steve


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## LeftyTheBandit (Sep 13, 2008)

Pawnbroker Bob said:


> Go to a local boat or marine/fishing supply. You can buy cast solid zinc anodes for boat motors and hulls. Not really cheap but available.
> 
> Pawnbroker Bob



This is a great place to get zinc. All boat hauls have zinc anodes and can be bought at marine supplies shops.


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## Lou (Sep 13, 2008)

Steve, you can use hot lye or potash solutions to dissolve silica. Alternatively, consider using ammonium bifluoride (''dry'' HF).

Story time:
Let's just say that I was dissolving some PGM sponge material that a member here had sent me. Everything was going fine but I kept seeing a recurrent precipitate that reminded me very much (it was a milky suspension) of something called Cab-O-Sil, which is basically fumed silica powder, a very, very fine powder. I removed it through microfiltration processes and this gummed up my filters and really ticked me off. What should've been a day's work became a week long endeavor.

I did a powder XRD on a sample of the material and confirmed my suspicions. I also dissolved a sample in HF and played around with it to see if I couldn't hydrolyze it back out in the filtrate but that's another story and another problem...


Anyway, long story short is that the zinc that _many _people here are using is contaminated with silica, SiO2. Steve's comment here in this thread helped me make the real causal link and establish that this is something that other people are experiencing rather than only the client who sent me his precipitates. It was the straw that broke the camel's back so to speak. I'm used to using pure zinc powder out of a supply house like Fisher--and that comes with complete analysis and any additives are noted. It's also murderously expensive to get it shipped (1200 mesh zinc is considered pyrophoric) so I hadn't considered possible reagent contamination, rather I thought it was residual artifacts from his other processes (which some still is!).

Now that I see others experiencing this phenomenon, I know what its cause is-- that fine silica powder decreases flammability and flowability and makes the material much easier to ship. It also makes it cheaper by adding bulk. I'm so thoroughly vexed at having my time wasted by these damn scoundrels selling inferior products to my customers and friends that I'm considering buying 100# of good material and parting it out!! Zinc is the premier material for dropping values. It washes out nicely, unlike iron and copper, it's also relatively cheap, and very fast, and also about idiot-proof. 

Again, *thank you* Steve for confirming my suspicions and you are right about garbage in, garbage out. I realize that not everyone has access to quality, standardized chemicals, but there is something beautiful about not needing to worry about what reagents you're using.

Lou


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## jimdoc (Sep 13, 2008)

Lou,
Count me in if you part out some bulk zinc.
Mine came from Ebay as well, and I would
rather avoid any problems when dealing with
pgm's. I am sure others will also realize that
buying from you would be a smart move also.
Jim


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## greentea (Sep 14, 2008)

I got zinc powder from a fireworks supply site. As far as I can tell, it is pure zinc. Kinda pricey but it got me going quickly.

http://www.skylighter.com/


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## qst42know (Sep 14, 2008)

If you look around on the pyrotechnic supply sites they also sell alumina ceramic grinding satellites made for grinding fireworks materials to fine powders in tumblers. If your source had ground less expensive zinc shot to powder themselves in a tumbler your powder will contain aluminum oxide dust as well. The fellow selling pyrotechnic supplies on ebay right now as well as three additional pyrotechnic supply web sites on the open web (one guy, four venues) indicated to me a commercial source for the zinc dust he sells.


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## qst42know (Sep 14, 2008)

That should have been three venues. Northstar/American/Jumpin jack flash pyro supplies. The source he indicated was http://www.purityzinc.com/
In the ultra pure line 325 mesh.


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## qst42know (Sep 14, 2008)

Mind you this is not reagent grade or anything. Perhaps PurityZinc could provide a more detailed analysis of their product.


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## Bernie Foley (Oct 27, 2008)

Hi,
I would think that zinc flashing would be low in sand but may have other metals in small amounts....have a good day!
Bernie


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## markqf1 (Oct 27, 2008)

Nobody wants to sell reagent grade zinc to individuals in large enough quantities to be economical.

Lou, the next time you order some, I would be willing to purchase some from you as well as pay you back for the zinc you've sent me.
In the meantime, If anyone knows how to get the sand out of it before using it, that wouldn't take forever or cost a fortune, please let me know as I have 5 lbs. that I would prefer not to toss out.

Mark


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## Lou (Oct 27, 2008)

Mark, next time you need zinc, I'll make sure you get the reagent grade material. Setting up an account with Fisher or another chemical supply house can be daunting (or these days, impossible) as it requires a business license/codes that specifies chemical industry or research lab. Don't worry about the zinc this time around.

Remember that you pay for the purity from the chemical supply house and it isn't cheap. Good news is, there are no questions about contamination when you order ACS reagent grade, it is what it says it is on the bottle. I think it will solve your sand issues. 

As for getting the cab-O-sil fumed silica out of it, hell if I know. I think it's no good, unless you want to digest all of your metal precipitates in HF to get the damn sand out of them!!


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## lazersteve (Oct 27, 2008)

Mark,

I've ordered some solid zinc that I'll be turning on a lathe to make some pure zinc turnings. I should have the bars by the end of the week. I'll make some turnings this weekend and try them out. If they work fine I'll have plenty for sale (50+ pounds).

I'll keep you posted Mark.

If anyone else is interested I'll be selling the turnings on my website once I confirm their usefulness.

Steve


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## Lou (Oct 27, 2008)

I might be interested in the turnings assuming you can provide certs on the purity of the metal.

Also, I don't know about machining zinc, but if you use any lubricant for the cut, be sure to remove it with some sort of solvent!


Lou


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## lazersteve (Oct 27, 2008)

Lou,

I don't have the purity specs, but I can send you a sample when I get the zinc and you could analyze it if you like. I don't have access to any way to confirm it other than using some for a precipitation and seeing what residues I find.

I've tried two different forms of powdered zinc and I'm running into the same problem each time... a fine insoluble brown residue (sand?).

Steve


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## Lou (Oct 27, 2008)

Steve, I've had this sand issue happen to me while processing crude precipitates from several of my clients. It got to be so bothersome due to the destruction of my filtering setups and it was such a time waste, it was cheaper for me ultimately to spend the $35/lb on reagent grade ACS certified zinc which I _know_works. I shipped it out to some people here to save me time and help them get on track. Inferior reagents: garbage in, garbage out.

For me, it is a very fine silica flour that has come up multiple times and powder XRD indicates it as being silica. I talked to some friends about it and was told that it is Cab-O-Sil, a fumed silica product that is used to improve flowability of the zinc powder and decrease its flammability. Conveniently it adds mass to the zinc, but it is not intended as a bulking agent. 
Regardless, it is a nuisance to be sure and has cost me some expensive frit glass filters and unnecessary delays in processing times!!!

I'm not so much concerned about metals contamination in your zinc as I am about insolubles like silica. I would be glad to assay a little bit of it and see what residues are left after digestion. I'd rather pay you top dollar for a product that works than send it to some supply house.

Regards,
Lou


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## Juan Manuel Arcos Frank (Oct 27, 2008)

I have been reading that you need pure zinc...well,you can use the zinc which is on spent batteries of Zn-C,this zinc is pure and you just need to get some spent batteries,take off their steel cover then you will see a grey cilinder,this is the zinc,take it off,wash it with tap water and melt it the way you need,shot or slab.

Prefer batteries made by Sony,Panasonic,Sharp,GE,Maxell...and try to avoid batteries made in China because these ones could contain mercury.

I have used this zinc to refine silver.

There are many tons of zinc waiting for you outside.

Best regards

Manuel


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## Oz (Oct 28, 2008)

Is there any reason not to use die cast zinc EMT Conduit Fittings? You do have to watch that you don’t buy aluminum die cast but I usually just see the zinc. The screws are usually steel so need removing before use. Here are a couple pics…


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## Harold_V (Oct 28, 2008)

They are not pure zinc. I dissolve them to make a treatment for moss on our roofs. There's traces of copper in them. I would seek a different source. They could be contaminated with other elements I don't know about. 

Harold


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## Oz (Oct 28, 2008)

I had some set aside and wondered about the purity. If someone knows greater details I would be interested, as there are cases were the copper would not bother me, but that leaves the question of other contaminates that may.


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## qst42know (Oct 28, 2008)

Many alloying elements are included to improve mechanical and casting properties.

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

Dozens of alloy variations have been developed and are possible.


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## butcher (Oct 28, 2008)

Lou I noticed you mentioned hot caustic soda to break the silca instead of HF, can you elaborate?
I was thinking CPU
would very high temperature (oxy-torch) then maybe dropping in ice water then boilng in caustic help before crushing help?
or change the SiO2 chemically ?
or once ceramic is (it just crush then burn to sand consistancy as I do now) gotta be a better way


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## Oz (Oct 28, 2008)

Well so much for that, I sure don’t want aluminum in my reactions!


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## markqf1 (Oct 28, 2008)

Thanks Lou, but I'm sure that you would agree that HF is a little too expensive to use for cleaning it up. I'll save it for further use that doesn't involve rh.
Steve, 
That sounds like a great idea. Be sure to keep me posted and count me in if your results are what you expect.

Mark


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