Alexander Mikhailov wrote: > > Hi, > > Dave is working on the freezer to make concentrated > HTP out of lower-grade one, AFAIK. The logic, I > assume, according to > <http://www.h2o2.com/intro/properties/pic11a.gif>, is > the following: if you have a 30% (or some other lower > grade) HTP, and start cooling it, first the water > becomes ice, and only then the peroxide itself > freezes. So, at the intermediate state you can remove > the liquid, which will represent the higher grade of > HTP. If you have peroxide stronger than, say, 65%, the > peroxide will freeze first, so you'll get the ice of > strong peroxide, which you can then melt to get HTP. > > The freezing is preferrable to sparging in that it > doesn't encourage you to heat the peroxide to speed up > the process; heating is more dangerous than freezing. > On the other hand, you have to reach rather low > temperatures, like -60F, to make an ice for certain > concentrations. An ordinary freezer, AFAIK, can't > provide you with such temperature; you're better off > with dry ice, but it may have its drawbacks with > obtaining, storing, moving, handling etc. > > Is it possible to use liquid air, or LN2, to reach low > temperatures for HTP concentrating by freezing? Or is > there some other severe problems on this path? > > Alex
We've considered it, but it looks like the required quantities of LN2 would be awkwardly large... especially now that I'm getting down to the desired temperatures with mechanical refrigeration. (A domestic freezer won't reach -40 to -60 F, but this temperature range is within the capabilities of commercial compressors.) -dave w _______________________________________________ ERPS-list mailing list [email protected] http://lists.erps.org/mailman/listinfo/erps-list
