[alt-photo] DIY ferric oxalate

[Erich Camerling]

Dear Gordon,

Herewith the instruction for making iron(III) oxalate : Fe2(C2O4)3  in 
solution (~27%).
Use disposable nitrile gloves and wear safety glasses.
Weigh out  :  25 g. FeCl3 (ferrichloride. CAS : 7705-08-0) anhydrous
           /_OR_/    40 g. FeCl3.6H2O  (CAS : 10025-77-1)
Put it in a glass cup (> 400 ml.) and add 50 ml H2O  (demineralized 
water !!).
Stir with a glass stirring rod till all the ferrichloride is dissolved 
(takes some time).
Add NH4OH (ammonium hydroxide solution .(CAS : 1336-21-6) = 5-25 % 
ammonia ) in small portions.
In the beginning it takes a form of brownblack dabs who disintegrate by 
stirring.
Adding more ammonia solution gives suddenly a sort of brownblack 
mud.This "mud" must smell weakly of ammonia.
If not : add a little bit ammonia,stir and smell prudent again.
( when you don't close the bottle with ammonia you will always smell 
ammonia !. *NEVER* smell on the bottle with ammonia.
That can be really dangerous.Smell _prudent_ on the "mud".)
Let the "mud" settle down for a few hours .Then pour off the liquid 
careful and pour  50 ml.H2O on the "mud".Stir well.
Let the mixture settle down for a few hours.Pour off the liquid etc.Do 
this 5 times.
After that : pour the "mud" on a filter (e.g.a synthetic coffee-filter 
holder  with a coffee-filter) and let is settle down overnight (or the 
whole day in the dark).
Ladle the concentrated "mud" careful from the filter into a clear cup. 
Add 14 g. C2H2O4.2H2O (oxalic acid dihydrate .CAS : 6153-56-6) Oxalic 
acid is poisonous !!. Don't inhale oxalic acid dust when pulverizing it 
before adding it to the concentrated "mud" .Stir well .This mixture 
becomes more liquid.
Pour this mixture on the used filter with the rest of the concentrated 
"mud" .The liquid who drops through the filter is the desired
FERRI OXALATE !!! (oxalic acid free ) So catch it in a brown glass 
bottle.Lay it in the fridge .It will stay well for ~3 months.
The filter with the  remnant "mud" is chemical  waste.

PS. Put all the used chemicals  and the solutions in safe keeping.
      Write on all the pots and bottles clear and durable what is the 
content and when it is bought or made.

For the chemists:
        2 FeCl3  +   6 NH4OH  --->  2   Fe(OH)3  +  6 NH4Cl

       2 Fe(OH)3  + 3 H2C2O4  --->  Fe2(C2O4)3  + 6 H2O

When you buy ferric oxalate _powder_ from B & S that will keep 
indefinitely !!!

Kind regards,

Erich