It depends. Silica gel will adsorb many substances, including water
molecules. If it is only water or other volatile substances, then the
answer is unlimited times, on condition that the recycling does not
cause discoloration. If there is a possibility of it adsorbing less
volatile substances, then the efficiency will diminish with time.
I suggest you weigh, say, 10 g of new, regenerated, gel, let it adsorb
as much moisture as possible under repeatable lab conditions, and
reweigh it. The delta-weight will represent its adsorbtion potential. Do
the same after, say, 20, 50 and 100 cycles of real use. If the
delta-weight has diminished by, say, 25% or more, scrap it, using that
number of cycles as your criterion for scrapping.
Scrap silica gel can be safely landfilled: after all, it is chemically
similar to quartz sand!
Brian
Sokkhon Ou wrote:
>
> A lot of parts were sealed with HIC and a bag of desiccant. They are
> reusable after reactivated. As part of the ISO14001, I would like to do
> my best. But I have concern that the materials shall disposed at on
> point in time.
>
> Can someone enlighten me about how many time can we recycle these
> materials?
>
>
> Thanks for your help.
>
> Sokkhon Ou
> Process engineer
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