question about potassium gold cyanid

[frank-20011]

Hello,

"What are you using to get SO2 gas? Are you using SMB to precipitate?"

Yes, after precipitation and after destroying the cyanide i use AR...than filtering and than SMB, not only gold settles but also a yellow sludge...i dry the sludge/gold and glow it, i'am only speaking about ~500mg


about my process: i work as crude as cody, i know nothing about the real cyanide level in my "cyanide" and so i can't say anything about it's concentration in my sollution and so on.

it "seems" to work fine and the alternative is the sulfuric acid deplating cell...

"You are testing CN with stannous"

yeees... a half drop of the sollution and a half drop of the acidic stannous sollution on a paper towel...
hokes say i should take 5ml of suspectet liquid and add HCL to wait for CN and "stand near a window"...that isn't viable to me!

thanks and regards!

 

[anachronism]

Also, I have probably handled 100,000 ounces of PGC in my life and have never smelled the smell of bitter almonds while doing this. I'm pretty sure that bitter almonds is the smell of HCN, the gas that is produced when cyanide, as either a salt or solution, is combined with an acid.

Hi Chris

The bitter almond smell comes even when working with a pH 13 solution. Are you sure that maybe you're just one of the many people who cannot smell cyanide?

 

[goldsilverpro]

Also, I have probably handled 100,000 ounces of PGC in my life and have never smelled the smell of bitter almonds while doing this. I'm pretty sure that bitter almonds is the smell of HCN, the gas that is produced when cyanide, as either a salt or solution, is combined with an acid.

Hi Chris

The bitter almond smell comes even when working with a pH 13 solution. Are you sure that maybe you're just one of the many people who cannot smell cyanide?

I can smell cyanide solutions. They supposedly have a straw-like smell and that's sort of what I think they smell like. Over a 4 year period in the early 70's, I visited several hundred plating shops. Every one I remember had huge vats of cyanide plating solutions. They usually contained at least 1/4 pound of CN/gallon and some held thousands of gallons. Here again, no bitter almond smell - strong straw like smell always. Very distinctive.

In the Air Force, I taught a 40 hour course, once a month, on Chemical, Biological, and Nuclear Weaponry. The school I attended for this had what they called a "sniff kit", to familiarize the students with the smells of the different chemical agents. This consisted of very large test tubes, each with a solution or substance in them, sealed with a stopper. One contained a substance that emitted HCN. To use these, one removed the stopper and sniffed it. You didn't sniff the mouth of the test tube. I seem to remember the bitter almond smell distinctly.

 

[anachronism]

Ahhhhhhhh now that makes sense!

That description of the smells is much clearer and makes a lot more sense if you pardon the pun.

I'm confusing the strong straw like smell with bitter almonds. Learned something valuable here, my thanks.

 

[frank-20011]

hello,

i didn't ask for any almond smell....i've only wrote about a strange yellow sudge which was formed within my gold percipitation.

i've glowed the gold percipitate together with the yellow slurry and it smells like SO2, mainly but also a little bit like Cl and ...?... but no problem about that, the problem was the sludge itself....these and my improvisitional cyanide "process".

how i should test cyanide sollutions for gold?

best regards, frank!

 

[goldsilverpro]

What in the hell does "glowed" mean?

Gold will form a yellow compound, AuCN, gold cyanide, insoluble in acid, when a PGC solution is acidified below a pH of about 3.5, if I remember right. We used to see it occasionally in inefficient acid (pH 4.3 optimum) gold plating solutions whose pH had been allowed to drop too far. Inefficiency in the amount of gold deposited per amp-minute can cause a pH drop.

 

[frank-20011]

hello,

sorry for my horrible english but i am here in an i-cafe and so i can't use spelling check....only my lousy school english!

"glowed" means: i've heated it on a steel sheet with propane burner from underneath until it glowes...after that it looks like precipitated gold should looks: red-brownisch....not yellow-greyish as it looks before!

best regards!

 

[FrugalRefiner]

Here, we usually call it incinerating. In college, we referred to it as igniting.

Dave

 

[frank-20011]

Hello,

i have more questions about...let us call it "codys cyanide": after the pins stand over night in the diluted cyanide (with or without H2O2) sollution the liquid get muddy-white (the right test tube) and than, if i add few drops of H2O2-3% the color gets from white to yellow (test tube in the middle) with a few more drops of peroxyde it gets bown (left tube)



is this the result off dissolved iron ions?

the 2nd thing is the question for a gold test in an alkaline cyanide sollution.

is my test possible? i add stannous in HCL to a single drop of gold-cyanide, made it acidic and the gold drops out by the stannous?


best regards!

 

[frank-20011]

Hello,

on an other place in the forum i have found GSP's statement to a cyanide test:

"There's a go-no go method in the Hoke book that takes a small amount of sample, acidifies it with HCl (under the hood), and then tests it with stannous chloride - I've never tried this. In my experience, though,"

and this is almost the test i've used, only in my stannous is so much HCl that i didn't have to add extra HCl!

i didn't found that in Hokes, only that one I've described above.

best regards!