A more likely explanation is that the zinc sulfate is mixed with the pumice powder
to form an abrasive mix (perhaps like cleanser). My recall of college geology
sent me to the textbook and pumice is volcanic ash that cools quickly trapping
many of the volcanic gases within it. Common uses for pumice are as a scouring
tool for cleaning porcelain and barbecue grills, a sanding tool and also for
smoothing callouses on the feet (human). It usually stinks during use when the
sulfur dioxide is released as the tiny air pockets break. The college text made no
mention of zinc in the chemical breakdowns for pumice. It is mostly volcanic glass
and air.
Pumice powder would be course volcanic ash. Once the bubbles are broken, the
material is mostly SiO2. The powder is highly abrasive and fine for polishing
things... or ruining them in the case of any auto or airplane engine that must
function in a volcanic region (like during Mt St. Helens' eruption). Hope this
helps.
Sabrena [EMAIL PROTECTED]
Nathan Tenny wrote:
> At 05:26 PM 12/13/00 -0500, Beverly Erlebacher wrote:
> > > From: [EMAIL PROTECTED]
> > > Date: Wed, 13 Dec 2000 17:09:33 -0500
> > >
> > > As of this writing, I
> > > have a bottle that was purchased from City Chemical in NYC, The label
> > says,
> > > Zinc Sulphate and in parenthesis Pumice Powder!
> >
> >Wow, that's pretty strange. If pumice the natural rock were actually zinc
> >sulphate, I'm sure the Canary Islands would have been mined to the water line
> >for zinc! I've never heard of pumice as a common name for zinc sulphate, but
> >they wouldn't print it on the label if it weren't true, eh?
>
> In trying to resolve this matter by appeal to the Web, I found a whole
> truckload of chemical supply sites that sell "pumice powder" and "zinc
> sul[f|ph]ate" as two different products. Perhaps City Chemical extracts
> its zinc sulphate from impurities in a particular batch of pumice, or
> something?
>
> On the Web site of a pumice supplier in Turkey
> (<http://www.ekokim.com/Pumice.htm>) I find the following:
>
> Pumice is a lightweight volcanic, sponge like aluminum
> silicate rock of igneous origin with a porous structure
> formed by a process of volcanism. This highly vesicular
> volcanic stone consisting mainly of silica SiO2. The high
> silica content (ca. 70%) positively affects the quality of
> pumice increasing the hardness of the material and its
> resistance to chemical attack.
>
> Further along they give a chemical breakdown of the pumice they supply:
> 69.9% SiO2, 14.3-14.9% Al2O3, 1.6-3% Fe2O3, much smaller amounts of TiO2,
> SO3, and MgO, and a bit of moisture. No mention of zinc.
>
> Weird.
>
> NT
>
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