Re: Sparging

>
>B. I think the route we're pursuing will potentially yield extra-pure
>(>98%) H2O2 with low impurity levels, as in the last batches XL-space
>supplied before closing: and the "squeaky clean & wicked pure" stuff
>has evident potential not only for catalytic work but also for potential
>hypergolic combinations. (Everything I've encountered so far leads me
>to the conclusion that if lower-concentration material is desired for
>use with a particular catalyst, best results will be had with highly-purified
>material (by way of a final freeze separation) diluted as needed, rather
>than with H2O2 concentrated by evaporation directly up to the intended
>strength (unless the evaporation starts with extremely low-solute material).
>
>This is not out of the question: the process used by Bengtsson of
>"Peroxide Propulsion Systems" in Sweden involves running the H2O2
>in dilute aqueous solution through an ion-exchange "demineralizer"
>as is used in preparing purified water: with solutes thus removed,
>he then concentrates the solution by evaporation.

I have said this several times in the past -- start with Solvay Ultra 
Pure at 50% concentration.  It reads zero on a TDS meter, compared to 
4 ppm for FMC propulsion grade.  You could concentrate an awful lot 
of that and still be at extreme purity levels.  We were getting it 
for $1 / lb in 500 lb drums.

John Carmack