Andie on fri 5 may 00
This message worried me. I have a recipe that calls for potassium
BIchromate, and just bought a little bag. How different is it from the
dichromate mentioned below? What are the health and safety hazards involved
in using it?
Andie
-----Original Message-----
From: Richard Gilbert
To: CLAYART@LSV.UKY.EDU
Date: Thursday, May 04, 2000 4:19 PM
Subject: Yellow Chrome Oxide
>----------------------------Original message----------------------------
>Hello Diane,
>
>You may have Potassiumdichromate (Potassium dichromate). It can be used
>as a colorant in glazes but it is very toxic. Potassiumdichromate is
>bright orange-red crystals or powder and soluble in water. You may
>want to try to deserve some as a test. If the chemical stains the water
>be careful it is also a fire hazard.
>
>http://www.uiowa.edu/~chemsafe/MSDS/PotassiumDichromate.htm
>
>Richard Gilbert
>Cherryville, North Carolina
__________________________________________________
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Tom Buck on mon 8 may 00
Angie:
There are two common compounds of potassium and chromium: 1)
Potassium chromate, yellow, K2Cr(VI)O4; and 2) Potassium Dichromate, (aka
BIchromate), yellowish red, K2Cr2O7 (Chromium is still hexavalent, ie, the
poisonous ion as Dr Edouard B has noted earlier).
Compound 1, K2CrO4 is declared to be highly toxic by ingestion and
inhalation. To be safe air should not contain more than 0.1 mg per cubic
metre. This compound is fairly stable and doesn't release free oxygen; it
melts at 971 oC.
Compound 2, the dichromate/bichromate is more reactive. It melts
at 396 oC and decomposes spontaneously at 500 oC. Like compound 1, it is
highly toxic by ingestion and inhalation (tolerance in air is the same
too). But unlike the other, Compound 2 is a strong oxidizing agent,
releasing free oxygen to combustible materials, ie, organic materials. It
has many uses in manufacturing.
Any potter using this dichromate should take extreme care at all
stages of handling this chemical. Personally, I would not stock this
chemical in my studio.
Til later. Peace. Tom B.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
On Fri, 5 May 2000, Andie wrote:
> ----------------------------Original message----------------------------
> This message worried me. I have a recipe that calls for potassium
> BIchromate, and just bought a little bag. How different is it from the
> dichromate mentioned below? What are the health and safety hazards involved
> in using it?
>
>
> Andie
>
>
> -----Original Message-----
> From: Richard Gilbert
> To: CLAYART@LSV.UKY.EDU
> Date: Thursday, May 04, 2000 4:19 PM
> Subject: Yellow Chrome Oxide
>
>
> >----------------------------Original message----------------------------
> >Hello Diane,
> >
> >You may have Potassiumdichromate (Potassium dichromate). It can be used
> >as a colorant in glazes but it is very toxic. Potassiumdichromate is
> >bright orange-red crystals or powder and soluble in water. You may
> >want to try to deserve some as a test. If the chemical stains the water
> >be careful it is also a fire hazard.
> >
> >http://www.uiowa.edu/~chemsafe/MSDS/PotassiumDichromate.htm
> >
> >Richard Gilbert
> >Cherryville, North Carolina
>
>
> __________________________________________________
> Do You Yahoo!?
> Talk to your friends online with Yahoo! Messenger.
> http://im.yahoo.com
>
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