Muriatic and it's "inert ingredients"

[yvonbug]

Recently,(as in the last year or two) I've had to use Muriatic acid instead of HCL reagent grade. I've noticed that I have a much more difficult time dropping out my gold than when I used the "stronger" stuff. Or should I say purer stuff? The Muriatic acid that I've bought is 31.45% with 68.55% inert ingredients. Can these inerts be affecting my results? I use Sodium Sulfite, photo grade, to drop my gold. Back when I used the 37% stuff, when I put the SS in, it would fizzle and fume, but the whirlpool of gold always happened, (once in a while it would flash in and out cuz of too much nitric still present) but usually the SS would eventually burn it out and the gold would drop out. Since I started using the Muriatic, there's really no fizzle, (still nasty fumes). and the gold doesn't show up. To the point of I eventually end up over dropping SS. If I leave it to sit for a while a very fine dusting shows, kinda plateing the glass. But nothing like it used to do. Trying to buy HCL now-a-days (here in California), They think you are a meth cook. I don't know if they red lined it yet. But it's getting real hard to come by, and sadly so is nitric.So can these inerts screw it up?-yvonbug-

 

[warrendya]

I've noticed that it's getting harder in CA to find 30% Muriatic. The other day I found the last jug at Home Depot, everything else is now 14-15%. Did you perchance use the weaker acid?

 

[lazersteve]

Y,

All I've ever used in my refining is Lowes 31.45% muriatic. I've never had any problems.

What you are describing sounds like the amount of dissolved gold is small. If you test the solution with stannous chloride after precipitate the 'fine brown powder' what is the result? If the test is negative then you have removed all the gold. If it is positive, perhaps you still have too much free nitric in the solution.

The other possibility is that your may need to concentrate you gold chloride solution more before adding any sodium sulfite. Very dilute (or dirty ) solutions tend to precipitate the gold as a fine powder that settles very slowly. Clean, concentrated solutions tend to precipitate the gold as a large spongy mass that settles in a matter of minutes.

Steve

 

[yvonbug]

Good Morning, Steve! You'er up early today. Or, no, You'er in Florida, 3 hours before us here in California. Maybe I'm just up late, or maybe, I'm just "late". Thank-you for the prompt response. I sat back and looked at the material I put into this batch, and, yeah, you'er probably right. Not much in, not much out. The stuff looked pretty good, and when it first started dissolving, put out a lot of yellow. But I was dissapointed later when I checked on it's progress to see it had become so much "bluer". I think that should have given me a clue. I should really check my mat'l better. You discribed it very well, what the results were and how it looked.
And what it is,
and what it's not.
Thanks-yvonbug-