The DI water used I would believe would be the number one contributor
(as Ben may have lead) funny thing is we used the purple menace to make
DI water at Radian.
Go figure?
-------- Original Message --------
Subject: [AR] Re: peroxide purity (was: HTP supplier)
From: qbert@xxxxxxxxxxxxxxx
Date: Sun, December 20, 2015 9:23 pm
To: arocket@xxxxxxxxxxxxx
We tried both freezing and an Ionic exchange filter and although both reduce
the levels of phosphate and other stabilizers we could not get all of it which
still led to inconsistency over a period of time. I am presently looking into
a
catalyst that apparently has a higher catalytic value than silver and not
susceptible to poisoning. Time will tell if it's a real thing or another wild
goose chase.
Robert
At 05:04 PM 12/20/2015, you wrote:
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