Making Phosphoric(v)acid

[gcol]

YT2095:

 

Just for you, secret, hush.

 

 

http://www.growell.co.uk/p/0130/pH_Up_and_Down.html

[KFC]

Witch one will, I don't have any yet? Will Superphosphate work?

[YT2095]

Lolly roffles @ gcol

dude, that`s where I buy my 38% Nitric from, I even have a catalog from them and discount vouchers, I just never realised they did Phosphoric also

 

KFC, what is Superphosphate???

I`ve seen Sooooooooo many agricultural and gardening and chem products called exactly that, which one is it????

[KFC]

Superphosphate = Ca(H2PO4)2

[YT2095]

oh cool! in that case you`re in luck

 

that`s exactly what I use too, you just need to add plenty water to dissolve it (it will freeze a little) but when it`s at room temp keepstiring and then fiter it, evap the water and get your Pure crystals.

 

you only need sulphuric acid (dilute) to finish the rest

[gcol]

YT:

 

I use the phosphoric to clean the alu and copper electrodes in my homebrew cells. This next bit is seriously off-topic, please forgive in advance, but:

 

1. If I have not washed the copper thoroughly afterwards, when put back in the cell electrolyte which contains caustic soda, a yellow coating appears on the copper. Is this yellow phosphorous?

 

2. If a piece of iron is put into the phosphoric, together with the copper, not only does the iron become copper coated, but it adheres so lightly that most of it falls to the bottom and forms a fluffy clump. After washing and drying, the copper dust is so fine it will disappear if I blow on it gently.

 

Just a couple of curiousities, probably of no practical interest to a real chemist.

[YT2095]

1, No it`s not Yellow phos (I wish it were that easy!)

 

2, it`s simple electrochemical displacement, and also perfectly normal

[KFC]

I have a ton of boric acid, could I use that instead of sulfuric acid, if so can you tell me the ratio I would need. Also, could I make other acids from Boric Acid?

[woelen]

@gcol: The yellow stuff most likely is hydrous copper (I) oxide, this has formula Cu2O.xH2O. It can have any color between brick red and yellow. Often it is somewhat brown, due to impurities (copper (II) species).

 

@KFC: With boric acid you unfortunately cannot make other acids. It is such a feebly weak acid, that from a practical point of view you hardly can speak of acid anymore. The only two acids, which really are good as a starting point for other acids are concentrated sulphuric acid (good for making HCl and HNO3) and concentrated (pyro)phosphoric acid (good for making HCl, HBr, HI and with some more difficulty HNO3).

[KFC]

Cool Thanks,

[bob000555]

Phosphoric acid is made industrially by reacting feldspar rocks with sulfuric acid over heat is it not? If so the ground in my area is full of the stuff you can hardy dig a hole with out hitting a bolder of the stuff, I don’t see why the developer built houses here and not a quarry. Do you think I could make phosphoric acid that way? What container should I use to withstand the HF byproduct?

 

edit: never mind they use Apatite not feldspar

[YT2095]

HDPE, HDPP and the likes.

 

just no glass/ceramics or metal as a general rule, I wouldn`t advise PVC either.

 

your project sounds interesting! something I myself would also attempt if I had such quantities, Have Fun but STAY SAFE!!!!!