Adulterated Titanium Dioxide

[ResolvableOwl]

I guess TD is not supposed to foam up like crazy when adding citric acid?

Above beaker holds about a tbsp of a titanium white pigment (artist grade, origin unknown to me), suspended in a bit of water, and a tbsp of concentrated citric acid solution added. At most, filled with liquid by 1/5 of its height.

This white powder cannot be pure titanium dioxide, because this would be unreactive with weak organic acids. I suspect it to be adulterated with chalk (calcium carbonate), which explains why it foams up when acidified. It is white enough, though, to assume that some high-performance white pigment is still present.

I only discovered this yesterday by chance when, for no specific reason, I didn't add citric acid to the lye first, but stirred it into the oils of a soap batch, after adding TD first – and saw/heard foam bubbles rise???

Not a big deal when this just means that soaps that use TD from this batch have a slightly altered white pigment composition. But what's less than optimal is that it invalidates my attempts at quantifying TD usage rates. Less TD than thought, might also explain why I had so little luck with glycerin rivers.

Looks like it's about time to switch to a reputable source for my titanium dioxide.

 

[jcandleattic]

artist grade

This white powder cannot be pure titanium dioxide,

With it being artist grade, personally I would not expect it to be pure, but that's just me. I deal with a lot of paint and art mediums, and no, they are not pure, and definitely not made for use on the skin.