When sing Sulfamic acid to denox AR wihout heat,,
is it best to use crystals or liquid?
is it best to use crystals or liquid?
Sulfamic Acid use
- Thread starter Paul73
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As far as I know, it have to be hot.
Most add a hot solution to hot AR.
Why do you need to do it cold?
Best hot. If you need a heat source you can use an old coffeemaker. They barely get hot enough but will also keep the boil overs down giving time to learn the reaction. Be sure to leave plenty of head space as the reaction can be quite sudden if there is a large excess of nitric. Smaller volumes work best on coffeemakers.
Some people use a solution and others just use the crystals.
I add the crystals to a still warm/hot solution with stirring and let it sit until room temp. After that I will add ice cubes or water for dilution depending on what metal I'm chasing. Then I filter the solution, any undissolved crystals (if any) will be filtered out.
The only reason I use the crystals and not a solution is waste solution control. I've limited myself to two 1 gallon containers (stock pots). That forces me to deal with it before it piles up on me. It sucks trying to deal with 5 gallon buckets full of waste solutions.
As Shark mentioned....Head space and only add a little at first so you can gauge the reaction.
I add the crystals to a still warm/hot solution with stirring and let it sit until room temp. After that I will add ice cubes or water for dilution depending on what metal I'm chasing. Then I filter the solution, any undissolved crystals (if any) will be filtered out.
The only reason I use the crystals and not a solution is waste solution control. I've limited myself to two 1 gallon containers (stock pots). That forces me to deal with it before it piles up on me. It sucks trying to deal with 5 gallon buckets full of waste solutions.
As Shark mentioned....Head space and only add a little at first so you can gauge the reaction.
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use heat, crystals will turn into liquid as they hit the solution, so either one works. don't use clumps of sulfamic, too reactive. Do use heat.
Well, that is one reason, but it is always possible to use some kind of gas heater.
It all depend on urgency.
The safest bet might be to weigh up a small button of Gold and put it in for a week or so.
Take it out and weigh it, to conform how much is redissolved.
Or if it is your Gold anyway, just let it sit until no more happen.
Drop the Gold with SMB and take it from there.
Thanks Yggdrasil but not set up here for a gas heater.
Urgency is low, just keeping busy processing some scrap stuff.
Urgency is low, just keeping busy processing some scrap stuff.
nickton
Well-known member
What about a propane torch?
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Even a candle or alcohol lamp burner would help.
I typically add free flowing sulfamic crystals with lots of stirring to a freshly reacted solution that is still warm from the reaction. In the winter months I use wrap around electric bucket heaters to drive my reactions, in the summer I simply add an appropriate amount of boiling water at the beginning of the reaction to kick start the process, the reaction self heats after that.
Sulfamic should be added before filtering so any undissolved crystals get filtered out. If not filtered off they slowly dissolve with a fizzing preventing the gold from settling quickly.
For PGM solutions near boiling heat is recommended, especially with Palladium.
As mentioned above, with sulfamic reactions ALWAYS use a catch basin and at least 1/3 of open reaction vessel head space. Add the sulfamic slowly with lots of stirring between additions. Not following these simple guidelines will cost you grief and likely money.
Steve
Sulfamic should be added before filtering so any undissolved crystals get filtered out. If not filtered off they slowly dissolve with a fizzing preventing the gold from settling quickly.
For PGM solutions near boiling heat is recommended, especially with Palladium.
As mentioned above, with sulfamic reactions ALWAYS use a catch basin and at least 1/3 of open reaction vessel head space. Add the sulfamic slowly with lots of stirring between additions. Not following these simple guidelines will cost you grief and likely money.
Steve
