In the News
What is Kaolin Clay?
Kaolin Clay is chemically know as aluminum silicate. For decades, glossy paper, the type used in magazines, was made using white clay called kaolin (named after the Chinese region Kao-Ling where it was mined to produce porcelain). Paper companies are now starting to switch over to calcium carbonate (chalk). Kaolin clay is also one of the most commonly used fillers or thickening agents in paint. In the US Kaolin is white clay (found primarily in Georgia and Alabama) that contains elevated levels of the uranium and thorium decay series. This clay is believed to be derived from the weathering of granites which are known to contain elevated levels of these radionuclides.
Below is a description of Kaolin from the "Boston Museum of Fine Arts". Please take particular note of the "Synonyms" for kaolin. Some less reputable companies will try to disguise their use of kaolin as one of their ingredients by listing one of the synonyms in a attempt to confuse the questioning customer.
Kaolin - A group of hydrated aluminum silicate clays. Kaolin's are primary clays formed by the weathering of aluminum
silicates such as feldspars and nephelite. When pure, kaolin is a soft, white, absorbent powder. Impurities may give it
a yellow, red, blue, gray or brownish color. It occurs at many locations around the world (France, England, Germany,
China, United States, etc.). Kaolin is used as a base for lake colors and as a filler in paints, cements and epoxies.
Kaolin (brick dust) has been used as an abrasive.
For a fuller definition go to http://en.wikipedia.org/wiki/Kaolin
An experiment was done in 1999 by Oak Ridge Associated Universities regarding measuring the radioactivity of magazines. You can read the results here www.orau.org/PTP/collection/consumer%20products/magazines.htm
I found it interesting they could actually get radioactive readings off magazines. Kaolin was also the primary ingredient in Kaopectate but apparently they changed the formula some 20 years ago from what I could dig up. I wonder why! Supposedly you can still get store brand products of a similar nature that still contain Koalin. There is also another phenomenon called Geophagia. Which is defined as "the practice of eating earthly substances such as clay". Apparently it can be quite additive as seen in the article at www.smokymountainnews.com/issues/3_01/3_07_01/back_then.shtml.
Some companies even go so far as to box and sell it but label it "Not for Human Consumption" knowing full well this is the purpose for which it is being purchased. A study from www.pubmed.gov lists the dangers of Kaolin in their article copied below.
Effects of geophagia (kaolin ingestion) on the maternal blood and embryonic development in the pregnant rat.
The point of it all is Kaolin may not be much of a problem when it is sealed into a paint film such as latex or acrylic, except for the radioactive nature of it. The problem arises when you breathe and ingest the dust. Other powder paints on the market are made with Kaolin Clay as part of their ingredients. I don’t know how you feel but my body is assaulted every day by pollution, radiation and stress. The last thing I want to do is work with a powdered paint that is labeled "Organic" and "Environmentally Safe" that puffs dust when I mix it, leaves a dusty residue that I can ingest when sanding, all the while polluting my shop with potentially radioactive material that may also be attacking my aging body. So read the ingredients of other paints and ask questions. You can be assured that Real Milk Paint® does not, never has, and never will contain Kaolin Clay.
All the Best