left overs from making nitric acid?

[Xsvfan1]

i have tried searching the forums and google aswell.
can only find stuff dealing with nitric acid itself.

i have made 3 batches of fuming nitric acid now. i have kept all the waste seperate inside of glass containers inside a wooden box packed in sand.
i am not comfortable enough with the waste procedure for the left over clump.

i use potassium nitrate and sulfuric acid then distill it. not 100% sure what to do with leftovers an want to make sure my information is correct before i do anything with them.

 

[butcher]

Potassium nitrate (KNO3) plus sulfuric acid (HNO3)

2KNO3 + H2SO4 --> 2HNO3 + K2SO4
--> produces 0r gives us a solution of Nitric acid in a mixture of potassium sulfate,

Using the heat of distillation we can distill off the nitric acid as toxic and corrosive gases, of the invisible (non water) soluble nitric oxide (NO) and the water soluble red nitrous acid (NO2).

The invisible gases of nitric oxide (NO) when mixed with the invisible air or oxygen will convert to the deadly red red gas of nitrous oxide (NO2) which is then water soluble.

2NO + O2 --> 2NO2

Now with the water and the soluble nitrous oxide gases dissolve so we get nitric acid.

3NO2 + H2O --> 2HNO3 + NO

After driving off all the water and nitric acid as gases we are left with a salt of potassium sulfate K2SO4.

Potassium sulfate can be used in chemistry just as we use many chemical reagents, to make other salts or reagents such as potassium bisulfate, which itself can be used to make nitric acid, or used to make other metal sulfate salts, like ferrous sulfate which we use to precipitate gold with , or to make copper sulfate salts used in refining of copper, or the potassium sulfate salt can used in many other chemical reactions...

The potassium sulfate can also be taken for disposal at your local hazardous waste disposal facility.

 

[Xsvfan1]

Thank you very much for the information. That was very helpful. I knew the left over powder block was potassium sulfate could be used for something I'm just as for what and how yet. Which is why I decided to treat it as waste. Maybe I'll hold onto it for now. Thank you sir.

 

[au-artifax]

Thank you very much for the information. That was very helpful. I knew the left over powder block was potassium sulfate could be used for something I'm just as for what and how yet. Which is why I decided to treat it as waste. Maybe I'll hold onto it for now. Thank you sir.

I will have to disagree with Butcher on this one. Yes, it is possible to double the amount of KNO3 to get potassium sulfate, but potassium sulfate's melting point (effecting the reaction vessel contents) is 1,958°F, so would not become liquid at all during the process. On the other hand, if you were to use half the KNO3 of what Butcher recommended, then you would get a liquid in the reaction vessel (which can boil, driving reaction the formation of HNO3 fumes), and get a product of KHSO4 (potassium bisulfate) which has a melting point of 386.6°F. Normally the synthesis of HNO3 using KNO3 and H2SO4 is done using a ratio of 98/101 (by weight) of H2SO4/KNO3.
I have done the reaction suggested by Buthcer, but it required extremely high temps, enough to completely decompose much of the HNO3 produced, under normal circumstances. The only way around it is to drive the reaction under the pressure of multiple atmospheres using dehumidified O2 and at extremely high temps.
Yeah, you get close to twice the HNO3 using the 2KNO3/H2SO4 formula, but you are wasting material, using twice the KNO3, and still only getting the same amount of HNO3 you would using half as much potassium sulfate. Stick to the old method and settle for having a byproduct of potassium bisulfate. The other way would leave you a mixture of unprocessed KNO3, some trapped HNO3, and KHSO4, which will completely crystalize after it cools.

 

[butcher]

With the formula given above most of your potassium sulfate salts are removed by chilling the solution, lowering the solubility of the K2SO4 salts as crystals which form in the freezing cold temperatures, the solution with a lower content of potassium sulfate is then decanted from these salts, and filtered cold, before using the solution as poor mans nitric acid.

For a higher purity product, where needed, the filtered solution of poor mans nitric acid can then be then distilled leaving the last remaining bits of potassium sulfate salts behind in the distilling flask.

au-artifax,
Note: I was not discussing making, or distilling fuming nitric acid, we are not making fuming nitric acid, there is no use for it in what we use nitric acid for in recovery or refining, we are not discussing making explosives on this forum.

I was attempting to answer the question of what the salts were and what can be done with them.

​

 

[slsmp40]

Potassium nitrate (KNO3) plus sulfuric acid (HNO3)

2KNO3 + H2SO4 --> 2HNO3 + K2SO4
--> produces 0r gives us a solution of Nitric acid in a mixture of potassium sulfate,

Using the heat of distillation we can distill off the nitric acid as toxic and corrosive gases, of the invisible (non water) soluble nitric oxide (NO) and the water soluble red nitrous acid (NO2).

The invisible gases of nitric oxide (NO) when mixed with the invisible air or oxygen will convert to the deadly red red gas of nitrous oxide (NO2) which is then water soluble.

2NO + O2 --> 2NO2

Now with the water and the soluble nitrous oxide gases dissolve so we get nitric acid.

3NO2 + H2O --> 2HNO3 + NO

After driving off all the water and nitric acid as gases we are left with a salt of potassium sulfate K2SO4.

Potassium sulfate can be used in chemistry just as we use many chemical reagents, to make other salts or reagents such as potassium bisulfate, which itself can be used to make nitric acid, or used to make other metal sulfate salts, like ferrous sulfate which we use to precipitate gold with , or to make copper sulfate salts used in refining of copper, or the potassium sulfate salt can used in many other chemical reactions...

The potassium sulfate can also be taken for disposal at your local hazardous waste disposal facility.

Potassium sulfate is quite a good fertilizer. I believe humanity spreads about 2,000,000 tons of it a year around. I don’t think you need to dispose of it as hazardous waste, but just responsibly dispose of it (orchards love it much as chloride of potassium fruit trees dont like so much).