But, as of the last time I asked him about it, is unwilling or unable
to provide an assay or other proof of compliance with chemical purity
standards.
On Sun, Dec 20, 2015 at 7:56 PM, Timothy Bendel, Frontier Astronautics
<Timothy.Bendel@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
XL Space deionizes (removes the phosphates and stannates) all the hydrogen
peroxide he sells.
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of David Weinshenker
Sent: Sunday, December 20, 2015 5:05 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] peroxide purity (was: HTP supplier)
On 12/20/2015 03:06 PM, Ben Brockert wrote:
On Sun, Dec 20, 2015 at 5:54 PM, Timothy Bendel, Frontier Astronautics
<Timothy.Bendel@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Thirdly, Carden's reliability is exceptional. In the several years
that he has been here I do not remember a single customer that has
said that he was not reliable.
Moon Express changed from XL peroxide to FMC after having catalyst
poisoning issues running XL. Of course it's always possible that the
contamination came from elsewhere, but there have not been similar
issues with FMC's stuff.
But, as mentioned, FMC is ~86%. So if you want anything higher (or
want to use it on a manned system) either you pay a lot for a large
batch from FMC, go with XL, find another supplier, or start your own
purification. Regardless of the approach, if you are using poisonable
catalyst like silver (not all catalysts can be poisoned) then you
should have the peroxide assayed for impurities.
In particular, phosphate (sometimes included as a "stabilizer") can poison
silver and some other catalysts - the motor will seem to start up OK one
time, and then after it cools down, the next run won't have very good
catalyst activity. (Rinsing the inactive catalyst with dilute nitric acid has
been observed to restore activity.)
This was driving ERPS crazy many many years ago - when we realized it was due
to the phosphate content in the H2O2 we looked at each other and said "no
wonder it's been so consistently erratic"!
"High test" (>80-85%) H2O2 with phosphate can be cleaned up by freezing; at
those concentrations the pure solid H2O2 freezes out first; this is denser
than the liquid (which retains ionic solutes such as phosphate.)
-dave w