Phosphate Reduction

[budullewraagh]

Industrial Method:

PO4-3 + C + SiO2 --(1500 or so celsius)-->P + SiO3-2 + CO2

 

the phosphate should be an alkali or alkaline earth.

the carbon alone COULD work, although it would require higher temperatures to oxidize the carbon to form the carbonate. at lower temperatures the phosphide would be produced instead.

 

as long as we are considering high temperature reduction, let us consider my recent hypothesizing:

 

PO4-3 + Al --(quite high temps but not as high)-->P + Al2O4-2

not too cost effective and certainly with low yield unless really high temperatures used

 

PO4-3 + Al + S --(considerably cooler than industrial method)-->SO3-2+Al2O3

my only reservation is the function of the S. the Al would oxidize immediately, then the sulfur hopefully would oxidize to the sulfite. of course, for this to work, one would have to use very little Al, which could mean high temperatures would be required.

 

 

 

in short, i think the carbon could easily be replaced by powdered Al, Mg, Si, As, Sb, Bi, Se or Te, but the most effective (for lower temperature reduction) would probably be Al.

 

now, as for the what could accept the cation(s) from the phosphate:

i am quite positive that one reducing agent (at low temperatures) would not be able to completely reduce the phosphate (eg: Si would not oxidize to SiO3-2, C would not oxidize to CO3-2). thus we need another acceptor. SiO2 is conventionally used but it takes quite a bit of convincing to oxidize further. i was thinking MnO2 would work well.

 

any suggestions/comments?

[jdurg]

Well, you have to take into account the cost as well. SiO2 is so incredibly cheap it's not funny. Go to a beach and there are TONS of SiO2 at your disposal. For the other metals you had mentioned, you first have to refine them, then produce them in a powdered form. In the long run, the cost of extracting those metals from their ores, then making them into a powder, would be more expensive than the methods they use now. That's one thing that a lot people seem to forget about when looking into industrial processing. On a small scale, it may seem easier to do something in one manner, but on a larger scale the one or two penny increase in price is magnified to a large extent.