Home Cosmetic Science Talk Formulating How to heat treat clay?

  • How to heat treat clay?

    Posted by Shelly1981 on June 12, 2020 at 3:49 pm

    Hi there

    I bought kaoline clay from Beraca. I used it in my formula and send the formulation for microbial challenge test. But the lab said it was pre-contaminated. I contacted beraca and they said if you open a package, you should use it immediately. But I had opened it a few months before.
    I’m wondering what is the best way to heat treat the clay to kill It’s bacteria? Is it possible to do it in an oven?

    Thank you so much!

    MarkBroussard replied 3 years, 10 months ago 3 Members · 5 Replies
  • 5 Replies
  • belassi

    Member
    June 12, 2020 at 4:45 pm

    That would depend on the moisture content.

  • Shelly1981

    Member
    June 12, 2020 at 5:58 pm

    @Belassi Do you mean moisture content of the final formula or the clay itself?

  • belassi

    Member
    June 12, 2020 at 11:37 pm

    the clay. It depends on how it comes. Has it been dried or is it more or less straight from the mine. If it’s dry you can easily sterilise it in the oven, it would be best to use an electric oven. I’ve no idea what your kaolin is like; mine is in 40Kg sacks and came from Starcast, a mining company in the southern US. It is nice quality but has a residual moisture content. The bentonite is a fine green powder from a mine here in Mexico that is said to be second only to the French product, but isn’t for direct application by itself. I tried it as a mask on my cheek for ten minutes, and it turned my skin bright red and felt like a chemical burn. The strange thing is that it doesn’t seem to be terribly alkaline but it certainly has a terribly strong effect.

  • Shelly1981

    Member
    June 14, 2020 at 3:12 pm

    @Belassi
    I’s not really fine, it’s like very fine sand. I have no idea about the moisture content. I can heat it and send it for microbial
     challenge test.
    Do you have any idea how long and which degree I need to heat it?

  • MarkBroussard

    Member
    June 14, 2020 at 3:31 pm

    @Shelly1981:

    If you have a robust preservation system, you really do not need to “pre-treat” the clay … the preservative will resolve any pre-contamination issues.

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