# AP using high percentage peroxide- BE CAREFUL!



## The Refiner49er (Feb 20, 2008)

After running several batches using HCL/H2O2, I wanted to post the following observations. 

Using HCL and 3% peroxide at a ratio of 2:1 didn't seem to be very effective unless it was warmed, still quite slow at attacking the heavier or more resistant substrates. It works well on fingers and thinner Au coatings, but if you are processing outside and the temperature is less than 50 F, the reaction is impaired considerably.

I have just finished two runs of AP using 27.5% hydrogen peroxide- a pool shock product that Lou recommended. I used a ratio of 1000 ml HCL to 55 ml H2O2 ( 1/9th the volume of a 3% peroxide). The reaction was immediate and vigorous, the solution heated up moderately with observable vapor rising off the container. It stripped the parts in a relatively short period of time.

I am in complete agreement with Lou, GSP, Irons and others in regards to minimizing the H2O in this solution. *But use caution*, *and add the peroxide a little at a time*, it is definitely hot stuff!

I am impressed with the effectiveness of a more concentrated solution.


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## banjags (Feb 20, 2008)

what was the pool product called? I am hoping I can find it in winnipeg. I would like to test it.


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## The Refiner49er (Feb 20, 2008)

> what was the pool product called? I am hoping I can find it in winnipeg. I would like to test it.



The product was called Soft Swim. There are probably a number of brands available, just call around to pool suppliers and ask for a pool shock with 27% hydrogen peroxide. Keep the lid tightly sealed to prevent the material from decomposing.


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## Gotrek (Feb 20, 2008)

Most pool shocks in Manitoba are Calcium Hypochlorite or Potassium Monopersulfate or Lithium Hypochlorite.


Those are the primiray ingredient of the three most commmon SHOCK type pool care products I don't recall seeing peroxyde on the ingredients list when I shop for pool supplies.


But I see that soft swim is marketed as the new chlorine free stuff and I've never looked for chlorine free stuff

BioGuard® SoftSwim® "C" Shock & Clarifier


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## banjags (Feb 20, 2008)

Indeed the BioGuard Softswim C is 27.5% hydrogen peroxide. $45 per gallon on one of the websites I found. regular peroxide would run a little less than half that cost but 9 times weaker. Hmm off to the pool store.


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## Gotrek (Feb 20, 2008)

Does Anechemia sell concentratred peroxide?

Answered my self tech grade 35% for 131$ x 4L


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## banjags (Feb 20, 2008)

ouch. the pool stuff would be the product to go with.


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## Lou (Feb 20, 2008)

Yes, be very careful with concentrated hydrogen peroxide. It becomes very dangerous at concentrations of 27% and above. 35% will bleach your skin and clothes instantly, 50% will give horrible boils and burns, and the 90% material will often explode upon touching organic material (it's also like maple syrup in consistency). That stuff is used as rocket fuel all by itself!


Also, let me mention that halides decompose peroxide (amongst other things, like fine metal powders, sunlight, and heat).

So if you do anything with peroxide, keep it away from bromide and iodide, it will rapidly decompose the peroxide, often explosively (I once had a steam explosion making bromine with peroxide solution).


Lou


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## Anonymous (Feb 22, 2008)

I am not sure of what exactly the contents are, but has anyone considered the peroxide that is used for bleaching hair by beauticians? if the higher concentrations are what turns skin colors and leaves burns, I would expect that this stuff would work. Have not even considered the cost factor. Will do some research and get back with yall.


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## Anonymous (Feb 22, 2008)

I was just doing some snooping around and found that you can buy a 15 gallon container of "food grade peroxide" which is 35% for about 1.50 / gallon (about $23 for the 15 gallon container). NOt sure how that stacks up, but I hope it helps someone. The cosmotology grade is, at most, 12% and costs more.


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## Platdigger (Feb 22, 2008)

Wow, were did you find it that cheap?
Randy


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## The Refiner49er (Feb 22, 2008)

I'm right with Randy, Tlute.

Please get back with a reference for that source for H2O2.

Sounds good to me.


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## Lou (Feb 22, 2008)

Likewise, that is an excellent price.
From that I can make reagent grade just by simple distillation, then titration to find concentration and dilution to a specific level. Beats $50/L from Fisher!


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## EVO-AU (Feb 28, 2008)

Lou, Wow, it does pay to look at other views. Randy had mentioned to me about using peroxide as an oxidizer with HCL. But I do a lot of stuff with Iodine. So I WILL BE SURE not to combine peroxide and Iodine. By the way, anybody ever use Lugols' Iodine ? It was used before the Civil War by prospectors in the same way that Hg fumes were used with a feather. Interesting process. Thanks, EVO


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## calgoldrecyclers (Mar 8, 2008)

i know where you can get 35% tech grade h2o2 for $23 a gallon.
hi- valley chemical and lab supplies. <--- on the web


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## banjags (Mar 8, 2008)

i just bought 40% yesterday for under $7 for one litre. At a beauty (salon)supply shop.


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## Lou (Mar 8, 2008)

Are you absolutely certain that it's not 40 volume?

If so, that is more like 10%.


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## The Refiner49er (Mar 8, 2008)

I would still like to find out where you can buy 15 gallons of 35% food grade peroxide for $23.00.

John


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## Platdigger (Mar 8, 2008)

Yea, at that price......you can sign me up for 1000.....to start...
Randy


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## tlcarrig (Mar 8, 2008)

Let me know if I'm blowing smoke here but I thought H2O2 degraded to water if left open and exposed to air and or sunlight. You are going to distill it to raise the concentration?


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## Lou (Mar 8, 2008)

It degrades over time but can be stabilised with something like H3PO4.

It is not so air sensitive as it is light and metal cation sensitive.
Bromide and iodide catalyze its decomposition.


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## skyline27 (Mar 8, 2008)

I picked up a gallon of 36% hydrogen peroxide for $16. Will this result in lower volume of waste/spent AP or am I missing something?


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## Platdigger (Mar 9, 2008)

This is good Skyline.

If you bought 3.6 percent (if there was such) it would take 10 gallons to equal the one gallon you just bought.

So, at lets say 2 dollars a quart......youda spent like 80 bucks.

You did well, care to share ware you found this great deal?
Randy


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## banjags (Mar 10, 2008)

Lou said:


> Are you absolutely certain that it's not 40 volume?
> 
> If so, that is more like 10%.



Ah crap it does say 40 volume. Check the MSDS it is 12%... not too bad a i guess. I will have to find a food service supply store. for the stronger stuff.


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## skyline27 (Mar 10, 2008)

A pool supply shop. The man was muttering about 1990's prices when he sold it to me. They also have super strength HCl. I'll probably avoid this. The standard HCl is plenty strong for my needs.


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## peter i (Mar 10, 2008)

And if you mix equal parts of 35% peroxide and concentrated HCl, it will heat up, start bubbling happily over the edge of the container and boil off HCl gas.

I intended to use it for cleaning MnO2 from glassware (which it does very effectively), but forgot to dilute it as I usually do after mixing. Well, we live to learn (if we survive, that is).

Also, be very careful not to mix organic solvents with acidified peroxide. The formation of highly explosive peroxides may occur. It is not an uncommon source of laboratory explosions (and quite a few maimed garage chemists!).


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## skyline27 (Mar 10, 2008)

For those of you who have used strong H2O2 in AP ...

Is the resulting gold foils or powder any different than using 2% H2O2?
My impression is that it would put more gold into solution than normal and result in more powder (as opposed to stripped foils and a little bit of powder)


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