What is kaolin and why is it so important in the management of hazardous materials at Sandy Ridge?
Sandy Ridge is abundant in kaolin, with a bed up to 36 metres thick and around 70-million-years old.
Kaolin is a commercial term used to describe a light-coloured soft and earthy rock comprising predominantly kaolinite together with quartz, feldspar, muscovite/illite, biotite, anatase and iron oxides/hydroxides.
A soft white clay that is naturally highly absorbent, with non-swelling properties, kaolin is a versatile material used in ceramics, pharmaceuticals, toothpaste, cosmetics, paper coating, paint, rubber, and fibreglass among other things.
It occurs as minute pseudohexagonal stacked platelets ranging in size from 0.1 to 10 microns. The platy structure partially gives kaolinite its unique desirable mechanical, rheological, plasticity, thermal and brightness properties. Kaolinite has a neutral pH level making it ideal for use in pharmaceuticals, cosmetics and many industrial mixes as it doesn’t alter the product composition and does not promote bacterial growth. It is a non-swelling clay that is naturally highly adsorbent, so it can help extract and remove undesirable impurities, pathogens or other substances in any given mixture or application.
Kaolin’s low permeability and adsorptive properties makes it ideal for a geological repository, where it seals hazardous material and counteracts leaching.