Sciencemadness Discussion Board

MeOH or DH2O for Purifying Ca(NO3)2 fert by disolving & filtering then evap.

RogueRose - 11-1-2018 at 17:44

I've mainly done the water process where I add enough to dissolve the fertilizer and I get a grey/brown oily sludge on the top which is maybe 1/2 of 1% of the total weight of the solid fertilizer (and some of that is water surely). the scum is oily and greasy (would REALLY clog hydroponic setup!!!!).

The result of my filtration (slow through tightly packed cotton balls) of about 20-30 drips a second until finished (say a 2L run will be left over night and is usually finished). The result is a completely clear product with a VERY slight yellow tint in some cases (not with the Yara - Norwegian - products, but with the local "generic"). I've also noticed a decent amount of ammonia gas production when adding a base (especially some K/NaOH) to the granular Yara brand CalNit). It would heat and the ammonia would escape very easily. This also happens when the prills (Yara) are dissolved in boiling water and then cooked on the stove (boiled), and ammonia smell is produced - BUT I have not noticed ammonia smell with the Generic version of the product (which was about the same price).

I have 2 good options for dissolving my nitrate, hot water or MeOH,

MeOH with the tetra hydrate dissolves at the following temps:
1.34g/ml @ 10 C
1.44g/ml @ 40 C
1.58g/ml @ 60 C

DH2O
1.05g/ml @ 0 C
1.29g/ml @ 20 C
3.63g/ml @ 100 C

it is actually more soluble in MeOH below 40C which is interesting.

I plan on doing 2 things. One is to recrystallize for easy later use, so that it is clean and ready to use. This needs to be dry and I’m leaning towards MeOH fo this.

Are there any benefits to using one over the other for the dissolving and filtration? I can evaporate off all the MeOH first, before adding to the H2SO4 if need be.


Then I tried a HNO3 synth on a small scale. I found that I would make a 30% solution (maybe dropped it to 25 towards the end) of H2SO4 and then allowed the filtering CalNit solution (dissolved in water) to drip into the acid a t a very slow pace and this gave a very homogenous and super fine precipitate of CaSO4. As compared to pouring a 25-30% solution of H2SO4 into the filtered CalNit solution - which left large SOLID chunks of CaSO4 that had to be broken up with an "electric stick blender - similar to a blender). This wasn't necessary with the slow addition (while the CalNit filtered, it just dripped into the H2SO4 and created a very nice precipitate and mix. I just now need to distill off the filtered solution and the CaSO4 is pure white with a slight amount of sulfuric and nitric acid so I need to figure out how to neutralize later (probably water and washing soda then many washings).

The filtration of the liquid out of the CaSO4 work GREAT with vacuum (old Air conditioner compressor) but I've done near the same (filtered liquid out of CaSO4) and it worked well by settling, decanting, mising water i, etc. Any thoughts or suggestions welcome)



Rant on Gov reg's strangling small or family farms with their agencies and "regs"....
NOTE on the OUTRAGEOUS increase on fertilizer prices for the "average" and small farmer - NOT big corporate farms.
The price for Ca(NO3)2 is RIDICULOUS in comparison to ammonium nitrate at the per ton amounts. It is anywhere from 6-16x the amount per ton when the difference in available nitrogen content is considered and the rates are even higher when you find tha applications is much more difficult with the newer fertilizers, often having to buy stabilizers, emulsions, etc to allow for mixing with other "additions" where none of this was needed before the AN ban. The average cost for fert and nutrients seems to have increased by 200-1000% since the ammonium nitrate hullabaloo (an orchestrated attempt to destroy the American middle class working farmer similar to the great depression and land grabs).