Scdc5515
Member
is there a way to neutralize the SO2 gas produced after using SMB to drop gold? A way to reduce the smell that wont affect my stock pot?
SO2
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jadedalex
Active member
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There is. Neutralizing SO2 requires a scrubber meaning that you need a vessel to contain the fumes and scrub them with either Methyldiethanolamine (MDEA) which has an affinity for various Sulphur compounds or scrubbing it with a liquid solution of Caustic Soda. You might try building a tray that supports granulated Caustic Soda above your stock pot. This would act as an Absorbent to capture the Sulphurated fumes but this requires daily tending...I leave it up to you as to how to design such a contraption. Just be safe...
Scdc5515
Member
Thank you!
jadedalex
Active member
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No worries...
Quiklearner
Well-known member
SCDC: Just boil your solution after you separate the gold out of it. This will drive off the SO2 gasses that are dissolved. Best done outside or in a fume hood. Using the wafting technique, once you cannot smell "rotten eggs", let cool and then add to stock pot.
Or you could drop the Gold with ferrous sulfate, it doesn’t smell.
Or abscorbic acid which doesnt smell either.
PeterM
Well-known member
Jadedalex, I am needing to roast a sulfide ore, needles to say the sulfur smell will come off and scrubbing the fumes is going to be a nightmare but hopefully not impossible. I will try your suggested MDEA + Caustic. I have another need to scrub the fumes from an ore roast that has Ammonium Bi-Fluoride, do you or anyone else have any suggestions?
TK421
Member
Have you worked with Ammonium Bifluoride before? If not, I'd advise you to stay away. It absolutely must be scrubbed - unless you're way, way out in the desert, and have a strong breeze blowing the fumes toward a lake or river, you will likely expose yourself and your neighbors to highly toxic fumes. Even skin contact with NH4HF2 is often fatal, being an HF donor.
HF exposure is a horrible death. The HF dissolves calcium from your blood, creating calcium fluoride, which prevents the calcium from being used as an electrolyte. Your heart (and most other muscles) rely on calcium in your blood to transmit neurological signals - including those to your heart to tell it to beat. HF very quickly absorbs into the skin, and even a small splash contacting a patch of your skin the size of your hand is usually fatal, even if rinsed immediately.
Heating NH4HF2 just makes it 100 times more fatal, as you're likely to inhale the NH4HF2, creating HF in situ in your lungs, and there is NO TREATMENT for HF exposure like that. For skin exposure, calcium gluconate gel is literally smeared all over the patient's body, but it's only effective about 1/3 of the time. For most patients, the treatment plan is "Make them as comfortable as possible, and keep the morphine coming".
HF is not immediately painful, as it instantly destroys the body's calcium channels for the nerves in the exposed area. You literally will not feel it burning your skin.
Side note: jadedalex said either MDEA or Caustic Soda, not both. The tray he mentioned would be something similar to a tray of sodium hydroxide chips laying in a shallow tray to absorb sulfurous and acidic fumes, but as he wisely said, he'll leave you to figure out the safest way to do that. Caustic Soda (Sodium Hydroxide) is a very dangerous chemical, and a tray of it tipping over after it's absorbed a little liquid can burn your skin and destroy your chemistry project - sometimes explosively.
HF exposure is a horrible death. The HF dissolves calcium from your blood, creating calcium fluoride, which prevents the calcium from being used as an electrolyte. Your heart (and most other muscles) rely on calcium in your blood to transmit neurological signals - including those to your heart to tell it to beat. HF very quickly absorbs into the skin, and even a small splash contacting a patch of your skin the size of your hand is usually fatal, even if rinsed immediately.
Heating NH4HF2 just makes it 100 times more fatal, as you're likely to inhale the NH4HF2, creating HF in situ in your lungs, and there is NO TREATMENT for HF exposure like that. For skin exposure, calcium gluconate gel is literally smeared all over the patient's body, but it's only effective about 1/3 of the time. For most patients, the treatment plan is "Make them as comfortable as possible, and keep the morphine coming".
HF is not immediately painful, as it instantly destroys the body's calcium channels for the nerves in the exposed area. You literally will not feel it burning your skin.
Side note: jadedalex said either MDEA or Caustic Soda, not both. The tray he mentioned would be something similar to a tray of sodium hydroxide chips laying in a shallow tray to absorb sulfurous and acidic fumes, but as he wisely said, he'll leave you to figure out the safest way to do that. Caustic Soda (Sodium Hydroxide) is a very dangerous chemical, and a tray of it tipping over after it's absorbed a little liquid can burn your skin and destroy your chemistry project - sometimes explosively.
As far as I remember, none of the previous posts mentioned AmmoniaBiFluoride nor HydroFluoric acid.
So why you brought this up here, in this post, I really do not know.
As far as I'm concerned and know, neither compound have a use in refining. At least not that can't be done with safer compounds.
Can you please be so kind and elaborate, and educate us, about why you brought this up here?
Regards Per-Ove
TK421
Member
Yes - the comment directly before me (from PeterM) said he was looking for a way to scrub fumes from ore that contained Ammonium Bifluoride:
How do ammonium bifluoride get into the ore ? It is the natural component of it or it is some toxic mining waste you are trying to process ?
Fluorides are no joke. No warning, they just kill you, not so much doctors in emergency room can do about it. And selecting one of the worst candidates - ammonium bifluoride - to work with... Very unstable compound, which decompose to it´s constituents very easily. Liberating HF on heating, poisoning whole local area if done on bigger scale. You can spend hours and hours to build working scrubber for this operation, but in the end, you just produce toxic fluoride waste anyway.
I will advise to stay away of any fluoride stuff, far far away. Not worth the risk, absolutely. Also with industrial aluminium making, there were so terrible consequences in the past, issuing fluoride contamination. Many times irreversible, costing numerous human lives.
Thanks for correcting me, I did not see that.
Regards Per-Ove
I did a search, and there are no references that ammonium bifluoride exist in nature, so I wonder if he is planning to use it instead of HF to etch away quartz.
Bad idea in both cases.
Please do not do that.
Bad idea in both cases.
Please do not do that.
In our university, our glass technician (retired) many times tell stories about creating some complicated chemistry apparatus back in the day. And he also mentioned his fellows, who etched the graduated cylinders and volumetric flasks with mixtures of hydrofluoric acid. Or etched some ornaments into glass vases etc.
"They do not last long in good health and all passed away before 50. Losing teeth, osteoporosis, heartattacks... "
Sobering to hear these kind of stories.
There is a reason HF or basic fluorides are not used in ore processing. Just few examples like fluorspar or cryolite for thinning the slag. And this is also quite hazardous in some aspects.
