philddreamer
Well-known member
Thanks Palladium!
I've been cought up on 3 projects & forgot to follow thru.
I've been cought up on 3 projects & forgot to follow thru.
evaporating the Nitric acid
- Thread starter Refiner232121
- Start date
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Whenever I have to incinerate (powder's filters and so on) I will use a hydroxide solution to rinse them, and then several washes to remove salts formed.
my thinking here is that roasting gold with chlorides gold can be volatile, even when roasting with salts the gold can form chlorides and some will evaporate. silver chloride is also volitile, the hydroxide can help to make it silver oxide.
There is no need for alcohol (I have to admit I have used alcohol to wet fine powder to keep it from blowing away), and gasoline could be very dangerous.
if much powders they can blow away if torch too strong and brought too close too fast, so heating with just the tip of the flame until they start fusing and paper or volatile carbon that blows around easily has been incinerated, then torch can be turned up and heated hotter, (some may use torch on bottom of pan), I usually use a propane or electric hot plate or coal fire to heat from bottom and torch to heat top, crushing and stirring well to expose all powders to oxygen and heat, heating to red glowing hot and keeping on heat as close to hour as I feel needed, the gases that come off depend on chemicals you used, and what is formed chemically during the roasting procedure, they come off in somewhat of an order like water then NOx then chlorides with sulfates being very hard to get oxidized and to fume off (sometimes I may add some fine iron powder if I have sulfides in these fusions.
some powders (I call them metal salts {metal + acid is a metal salt of that acid}) some powders will dry then change to a syrup, (fuse), continued heating will drive off more acidic gases then these powders will then dry again and as all acids are fumed off will stop smoking and glow red hot.
Caution these fumes are deadly, or can give you breathing troubles later in life. They are also very corrosive to anything close to where you do this work.
my thinking here is that roasting gold with chlorides gold can be volatile, even when roasting with salts the gold can form chlorides and some will evaporate. silver chloride is also volitile, the hydroxide can help to make it silver oxide.
There is no need for alcohol (I have to admit I have used alcohol to wet fine powder to keep it from blowing away), and gasoline could be very dangerous.
if much powders they can blow away if torch too strong and brought too close too fast, so heating with just the tip of the flame until they start fusing and paper or volatile carbon that blows around easily has been incinerated, then torch can be turned up and heated hotter, (some may use torch on bottom of pan), I usually use a propane or electric hot plate or coal fire to heat from bottom and torch to heat top, crushing and stirring well to expose all powders to oxygen and heat, heating to red glowing hot and keeping on heat as close to hour as I feel needed, the gases that come off depend on chemicals you used, and what is formed chemically during the roasting procedure, they come off in somewhat of an order like water then NOx then chlorides with sulfates being very hard to get oxidized and to fume off (sometimes I may add some fine iron powder if I have sulfides in these fusions.
some powders (I call them metal salts {metal + acid is a metal salt of that acid}) some powders will dry then change to a syrup, (fuse), continued heating will drive off more acidic gases then these powders will then dry again and as all acids are fumed off will stop smoking and glow red hot.
Caution these fumes are deadly, or can give you breathing troubles later in life. They are also very corrosive to anything close to where you do this work.
philddreamer
Well-known member
Thank you Butcher! 8)
Well Phildreamer, I cannot say that I do it right but that is how I do it untill I know better.
I am just amazed at how fast you have been learning all of this, and always like reading your posts and answers, you are a valuable asset to the forum in my mind. And I just love seeing those gold pictures you post.
I am just amazed at how fast you have been learning all of this, and always like reading your posts and answers, you are a valuable asset to the forum in my mind. And I just love seeing those gold pictures you post.
philddreamer
Well-known member
I thank you for leading me in my first steps & explaining the "why" of things; I owe a lot to you for been so patiente.
This is a great forum!
This is a great forum!
Hi butcher
Thanks for your help and the help of others.
I was wondering about boiling nitric acid and the material to be refined.
Here the silver mixes in with the nitric and I was wondering if you boil the solution does the silver go up in vapour
Thanks again
Thanks for your help and the help of others.
I was wondering about boiling nitric acid and the material to be refined.
Here the silver mixes in with the nitric and I was wondering if you boil the solution does the silver go up in vapour
Thanks again
philddreamer
Well-known member
Hi Frank!
If I may, it seems you're processing silver. The silver doesn't mix with the acid, it dissolves. If you boil the nitric & you don't have a cover, like a watch glass, you will loose silver.
If I may, it seems you're processing silver. The silver doesn't mix with the acid, it dissolves. If you boil the nitric & you don't have a cover, like a watch glass, you will loose silver.
PreciousMexpert
Well-known member
Hoke says to boil.
I guess not to long.
As soon as the silver dissolves than thats all you need
I guess not to long.
As soon as the silver dissolves than thats all you need
I do not believe Hoke meant boil even though that is a term used to describe heating a solution by many of us before we realized the problems of using this word incorrectly.
Notice Hoke talks of using steam table for evaporating nitric acid, it would not boil the acid as the temperature would not get hot enough (unless steam was under High pressure and that is not the case here), the words we choose can have different meanings to different people, or we may use a word to describe a process and use a term that really does not describe the process as it should, and would cause problems for others if they took our word literally, that has been something that stands out in this forum in my mind, everywhere I have read the aqua regia process they spoke of boiling to rid nitric acid, here on the forum I learned the proper method slow evaporation.
Boil your aqua regia and you will loose gold, and you may just loose it all at once in one big boil over as nitric concentrates in solution.
Edit to add:
When dissolving silver your nitric is diluted to about 30 -40%, there is plenty of water and metal to dissolve, fume would contain mostly water and some NOx gases, (silver nitrate is not volatile that I know of like gold chloride is), a watch glass cover should always be used, they are good indicators of what your fumes may contain, and in my case keeps out the oak tree leaves and bugs, boiling the nitric when dissolving silver is not necessary, and I just heat mine just under the boiling point, to speed thing up, as when boiling the popping of gas bubbles will carry values and you can loose silver with them, even cold the silver will dissolve it just takes forever, heat speeds reactions of acids on metals.
Editted again: So I would not annoy Harold, by using their when I meant there.
Notice Hoke talks of using steam table for evaporating nitric acid, it would not boil the acid as the temperature would not get hot enough (unless steam was under High pressure and that is not the case here), the words we choose can have different meanings to different people, or we may use a word to describe a process and use a term that really does not describe the process as it should, and would cause problems for others if they took our word literally, that has been something that stands out in this forum in my mind, everywhere I have read the aqua regia process they spoke of boiling to rid nitric acid, here on the forum I learned the proper method slow evaporation.
Boil your aqua regia and you will loose gold, and you may just loose it all at once in one big boil over as nitric concentrates in solution.
Edit to add:
When dissolving silver your nitric is diluted to about 30 -40%, there is plenty of water and metal to dissolve, fume would contain mostly water and some NOx gases, (silver nitrate is not volatile that I know of like gold chloride is), a watch glass cover should always be used, they are good indicators of what your fumes may contain, and in my case keeps out the oak tree leaves and bugs, boiling the nitric when dissolving silver is not necessary, and I just heat mine just under the boiling point, to speed thing up, as when boiling the popping of gas bubbles will carry values and you can loose silver with them, even cold the silver will dissolve it just takes forever, heat speeds reactions of acids on metals.
Editted again: So I would not annoy Harold, by using their when I meant there.
philddreamer
Well-known member
Thank you Butcher!
Butcher wrote:
"Boil your aqua regia and you will loose gold,..."
The novice can learn to tell when the solution is too hot by, watching the color of the drop on the watch glass. If the drop is the same color of the solution, you're evaporating values! The drop should be clear. Train your eye to recognize the difference between boiling bubbles & reaction bubbles.
Reaction bubbles are small & you'll have red fumes in your vessel. Boiling bubbles are much bigger & the fumes in your vessel will be more the color of the solution.
"...and you may just loose it all at once in one big boil over as nitric concentrates in solution."
The novice also needs to learn that the reaction itself will produce heat.
If you are processing silver & you add ALL the nitric required @ once, but see no immidiate reaction for the next 5 minutes, the tendency is to crank up the hotplate. Well, when the reaction itself "kicks in" & produces its own sudden heat, plus your hotplate cranked up, chances are its going to boil over! Learn to control the heat of your solution. Once you've gained experience, & have learned how your solution will behave, then you can speed up the heating process.
Butcher, please, could you add more details.
Butcher wrote:
"Boil your aqua regia and you will loose gold,..."
The novice can learn to tell when the solution is too hot by, watching the color of the drop on the watch glass. If the drop is the same color of the solution, you're evaporating values! The drop should be clear. Train your eye to recognize the difference between boiling bubbles & reaction bubbles.
Reaction bubbles are small & you'll have red fumes in your vessel. Boiling bubbles are much bigger & the fumes in your vessel will be more the color of the solution.
"...and you may just loose it all at once in one big boil over as nitric concentrates in solution."
The novice also needs to learn that the reaction itself will produce heat.
If you are processing silver & you add ALL the nitric required @ once, but see no immidiate reaction for the next 5 minutes, the tendency is to crank up the hotplate. Well, when the reaction itself "kicks in" & produces its own sudden heat, plus your hotplate cranked up, chances are its going to boil over! Learn to control the heat of your solution. Once you've gained experience, & have learned how your solution will behave, then you can speed up the heating process.
Butcher, please, could you add more details.
Sorry Phil, my mind is blank; I do like your description of these reactions.
Do not fill your pots too full give them room for expansion, incase things start foaming up, a water squirt bottle is handy to spray the foaming and may help to keep them in the pot, (also a suction bulb can remove liquids before the overflow from the pot), catch basins are always handy for spills or if some glass breaks, I use fiberglass trays like they have in cafeterias.
Remember do not change temperature of your glass too fast thermal shock breaks them and always at the wrong time, also metal powder’s in the bottom of a pot on heat can over heat the bottom portion of the reaction vessel being heated and crack the bottom of the pot, if you must heat them keeping them stirred will keep them off the bottom.
If you do get a pot cracked at bottom on a stove, do not lift the pot, the bottom will most likely fall out and all the acids and gold with it, siphoning can remove the liquid.
One of my favorite tools is a suction bulb that looks similar to a turkey baster suction bulb, the hole is smaller they sell them where you buy lab supplies, it is very handy for transferring liquids, another tool are called pipettes similar to eye droppers they can pick up drops of solution from above powders, these tools work well for decanting liquids without disturbing settled powders, I even cut off top bulb of an old pipette and stick it onto my suction bulb to be able to pick up more liquid through the pipette orifice.
Do not fill your pots too full give them room for expansion, incase things start foaming up, a water squirt bottle is handy to spray the foaming and may help to keep them in the pot, (also a suction bulb can remove liquids before the overflow from the pot), catch basins are always handy for spills or if some glass breaks, I use fiberglass trays like they have in cafeterias.
Remember do not change temperature of your glass too fast thermal shock breaks them and always at the wrong time, also metal powder’s in the bottom of a pot on heat can over heat the bottom portion of the reaction vessel being heated and crack the bottom of the pot, if you must heat them keeping them stirred will keep them off the bottom.
If you do get a pot cracked at bottom on a stove, do not lift the pot, the bottom will most likely fall out and all the acids and gold with it, siphoning can remove the liquid.
One of my favorite tools is a suction bulb that looks similar to a turkey baster suction bulb, the hole is smaller they sell them where you buy lab supplies, it is very handy for transferring liquids, another tool are called pipettes similar to eye droppers they can pick up drops of solution from above powders, these tools work well for decanting liquids without disturbing settled powders, I even cut off top bulb of an old pipette and stick it onto my suction bulb to be able to pick up more liquid through the pipette orifice.
philddreamer
Well-known member
Excellent Butcher, I knew there were more details.
Thanks!
Thanks!
