[TheForge] Phosphate? (Ping Bruce the chemist)

[parkej7 at rpi.edu]

Not Bruce, but I took AP Chem a few years ago, so...
Iron plus Phosphoric Acid is known to create  Iron (2) and Iron (3) Phosphate, or ferrous hydrogen orthophosphate, even when the phosphoric acid is diluted. What you’ve got is almost certainly impure, but Iron 3 is used as a base in some kinds of metal coatings. Its presence in the Iron Pillar of Delhi is what supposedly makes it so rust resistant. 
It is also used as an organic pesticide!
If you’ve got enough volume of iron 2 phosphate, you can supposedly heat it to form vivianite, a crystal. 

> On Jul 16, 2018, at 17:37, Mike Spencer <mspencer at tallships.ca> wrote:
> 
> 
> I had a background in chemistry, too, but I was weak on inorganic and
> it was 50 years ago so...
> 
> I had some phosporic acid that I used to pickle some ironwork, maybe 3
> gal. diluted from the 80-something % as delivered.
> 
> It sat in a plastic gas can for years.  When I went to get some, the
> can held a large quantity of solid gunk and a murky supernatant.  Much
> shaking and proddind with a stick, dumped out a slurry into a tray,
> allowed the liquid to evaporate in the sun over several days.
> 
> Result was a thin layer of black stuff on top, I assume iron
> phosphate.  Scraped that off and allowed the remainder to dry.  It's a
> uniformly light grey, gritty granular substance.  Seems insoluable or
> only slightly soluable in water.  Will melt, perhaps with
> decomposition, on an iron bar when the bar is heated with a torch to
> orange heat.
> 
> Must be something-or-other phosphate but I can't figure out what it
> is.
> 
> What's my grey granular substance, Bruce, that came from phosporic
> acid in a closed container with only a litte iron contmaination?
> 
> 
> Feeling stupid, presbyphoria,
> - Mike
> 
> -- 
> Michael Spencer                  Nova Scotia, Canada       .~. 
>                                                           /V\ 
> mspencer at tallships.ca                                     /( )\
> http://home.tallships.ca/mspencer/                        ^^-^^
> 
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
> 
> TheForge mail list group photo site is
> http://www.shutterfly.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html