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Thread: Re-cycling Silica Gel - LIVE DEMO!!!

  1. #21
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    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Incidentally, I also dry my silica gel in the microwave, and we also use that microwave to heat food. I believe the fumes coming out should be the water that went into the silica gel, so should be not poisonous...

    If some of the silica gel itself is evaporating or getting into the food, then that would be a problem, but I believe the "fumes" coming out is just water.

    Microwave heats the silica gel to a very high temperature, and it heats very fast. Like someone mentioned, I believe it heats the SG right from the inside, and not just on the outside, which is why it is so much more blue at the end. However a disadvantage is, that sometimes, the SG cracks, from the high temperatures, so you tend to have bits and pieces of it in your bowl afterwards. If you touch the silica gel before it is properly cooled, they'll stick to your fingers, so be careful. (I think they burn a small piece of your skin and stick to it)

    I normally set the microwave to the lowest power and let it run for about 10 minutes.

  2. #22

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    hmmm okie did a bit of a search on why silica gel is harmful
    check out here
    http://www.envirogel.co.uk/material_...sheet_blue.htm
    http://ptcl.chem.ox.ac.uk/MSDS/SI/silica_gel.html
    so guess breathing in the dust is the bad thing... so be careful...
    and if you wash the gel u might wash away the coloring.. whcih is cobalt chloride which is toxic as well...

    and here's antoher link on how to recycle silica gel
    http://www.southernexposure.com/libr...ilica-gel.html
    Last edited by slaam; 4th January 2006 at 01:37 PM.

  3. #23
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    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Quote Originally Posted by moondancer
    Hi Slaam,

    Yup it emits a funny smell when i'm frying it, so those interested to try this should keep the fire low and open all windows to allow ventilation, and stand far from it.. I went to mop the floor when frying it so I dont stand there and inhale whatever's emitted!! ^_^

    Yah I tried putting it into a jar for it to cool, but it got all steamy (cos its still very hot) and start to absorb all the water vapour again before I can say SILICA!!! what to do???

    And yup, I've tried using the mini size hungry hippos from $1 shops, its good, but you can forget to change it when all became flooded with liquid and thats a bad thing... and also there's a danger of spilling it in the dry box!!! Guess silica gel is dry and safe lor...
    When silica gel is cool, water from the air will be absorbed into the gel. When the gel is heated, the water is forced from the gel back into the air. The reason the silica gel looks all steamy after heating is because that's the water coming back out, and because the density of water molecules is high around the silica gel, they will tend to condense on cooler surfaces nearby like glass. So long as the silica is maintained at a higher temperature, that water will not tend to be reabsorbed into the gel. So the thing is to keep the gel at a higher temperature, until the surrounding water molecules have gone somewhere else. Then let the gel cool down again. If you put it in a jar and it gets steamy, I think that means you need to put it on the fire for longer. In fact from your photo of the dried gel, it doesn't have that deep blue colour, and looks like it could be heated for longer.

    Those web pages posted by slaam, seem to have varying information on them. Some say that it is not toxic, and some say it is. I've seen warnings not to eat it on foods in which they pack it with silica gel, but it can't exactly be poisonous if they pack it together with the food for months in storage/transit. From one of the web pages, (http://www.envirogel.co.uk/material_...sheet_blue.htm) they seem a little paranoid saying you should wear gloves before touching it, and wash hands thoroughly after touching. Anyway, always better to be safe than sorry, but from reading those pages, I don't get an impression there is a high risk. Of course no need expose yourself to it unnecessarily either. Thanks for the info slaam

  4. #24

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Please take note that the chemical used in the silica gel for the moisture indication is cobalt chloride and it is carcinogenic. http://www.jtbaker.com/msds/englishhtml/c4928.htm
    Last edited by lsisaxon; 6th January 2006 at 04:50 PM.

  5. #25

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Quote Originally Posted by moondancer
    Yeah..I think i'll try the microwave method too...sounds cool that the beads remain blue even after cooled....
    Will try when hubby's not at home (he's worried about the *poisonous fumes* and all...what he don't know can't hurt him haha!!
    My advice is still to get a proper dry cabinet. Uncoloured silica gels are ok but those with the colour indication contains cobalt chloride which is poisonous and proven to be carcinogenic. Even then, after frying, the silica will tend to fracture and you get silica dust which is not good for your lungs and also the image sensor.

  6. #26
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    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Quote Originally Posted by lsisaxon
    Please take note that the chemical used in the silica gel for the moisture indication is cobalt chloride and it is carcinogenic. http://www.jtbaker.com/msds/englishhtml/c4928.htm
    Maybe must ask goverment to ban it. Or at least vendor to put warning sticker "Carcinogenic" on Silica Gel bottle .

    Regards,
    Arto.

  7. #27

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Quote Originally Posted by Artosoft
    Maybe must ask goverment to ban it. Or at least vendor to put warning sticker "Carcinogenic" on Silica Gel bottle .

    Regards,
    Arto.
    Yeah. Better to be safe than sorry.

    Here are some more readings.

    http://www.cr.nps.gov/museum/publica...gram/02-15.pdf
    http://www.geejaychemicals.co.uk/cobaltchloride.htm
    http://www.jtbaker.com/msds/englishhtml/s1622.htm

    You can find a whole lot more using google search with the followind keywords: silica gel cobalt chloride
    Last edited by lsisaxon; 6th January 2006 at 04:46 PM.

  8. #28

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    I think the cause for concern is not large as listed on the site


    (1) Self-indicating (blue) silica gel is the same as it has been for 60 years - there has been no change in its formulation or composition.
    (2) Self-indicating (blue) silica gel has not been banned from use.
    (3) The new regulations apply to cobalt chloride not silica gel, so they do not apply to non-indicating (white) silica gel.
    (4) Self-indicating (blue) silica gel is still classified as non-hazardous for transportation.
    (5) As far as we are aware, these regulations apply only to European Community countries.
    (6) Some companies have carried out Risk Analysis on using the self-indicating
    (blue) silica gel and are continuing to use it with certain safeguards in place.
    (7) Self-indicating (blue) silica gel in beaded form or in sachets gives
    virtually no exposure to dust.

    the cancer risk appears to be from ingesting large amts of cobalt chloride and I think it can be eliminated from the body so its not like mecury an accumulative poison. add to the fact that only a little is added to the gel so its still being used.

    What I wont do is.
    1) wash the gel
    2) dun wash my hands and eat food after handling it)
    3) clear away the dust to avoid breathing it in..

  9. #29

    Default Re: Re-cycling Silica Gel - LIVE DEMO!!!

    Quote Originally Posted by slaam
    I think the cause for concern is not large as listed on the site


    (1) Self-indicating (blue) silica gel is the same as it has been for 60 years - there has been no change in its formulation or composition.
    (2) Self-indicating (blue) silica gel has not been banned from use.
    (3) The new regulations apply to cobalt chloride not silica gel, so they do not apply to non-indicating (white) silica gel.
    (4) Self-indicating (blue) silica gel is still classified as non-hazardous for transportation.
    (5) As far as we are aware, these regulations apply only to European Community countries.
    (6) Some companies have carried out Risk Analysis on using the self-indicating
    (blue) silica gel and are continuing to use it with certain safeguards in place.
    (7) Self-indicating (blue) silica gel in beaded form or in sachets gives
    virtually no exposure to dust.

    the cancer risk appears to be from ingesting large amts of cobalt chloride and I think it can be eliminated from the body so its not like mecury an accumulative poison. add to the fact that only a little is added to the gel so its still being used.

    What I wont do is.
    1) wash the gel
    2) dun wash my hands and eat food after handling it)
    3) clear away the dust to avoid breathing it in..
    I agree with this but I think better safe than sorry. I have been using blue-red silica gels for many years before switching to dry cabinets. I recently stumbled upon the cobalt chloride safety data and was shocked at the information, so I thought better safe than sorry.

    Anyway, even if non-indication silica gels are used, the dust (especially from trying to recycle the gels) can be quite bad for DSLRs.

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