SimpleChemist-238 - 17-5-2015 at 13:14
I have never gotten and good yields from conventional means of the synthesis of nitric acid from distillation of the acid and its side products so I
purchased 1 pound of calcium nitrate from Amazon.com ( 99% Ca(NO3)2 for 10$.) Calcium sulfate is not very soluble in water so my plan was the
hydrolysis the salt to calcium sulfate with diluted sulfuric acid. After addition the solution is stirred for 30 minutes. Then letting it cool and
filtering.
1 mole of calcium nitrate or calcium ammonium nitrate (about 164g or so) is dissolved in 20ml of distilled water to make a slurry. It is chilled and
added to a 300ml flask. Then 50ml of 98% sulfuric acid is drop wise stirred into the solution. A thick muddy precipitate of calcium sulfate will form.
After the addition of acid the contents flask is filtered and the liquid is kept. The acid should be yellowish clear and its conc. is about 60 to 71%.
I tested my acid by adding 25ml of it to a 30g copper bar. The reaction evolved great amounts nitrogen dioxide.
Related and source sites
http://en.wikipedia.org/wiki/Calcium_sulfate
http://en.wikipedia.org/wiki/Solubility_chart
Pictures
[Edited on 17-5-2015 by SimpleChemist-238]
subsecret - 17-5-2015 at 13:44
Distillation of the acid will produce a product that is mostly free from contaminants. Add a stoichiometric amount of water to the calcium nitrate
beforehand so you can reach the 68% HNO3/H2O azeotrope.