Menu

Understanding kaolin clay- it’s importance and critical mineral potential

Ever wondered about the precise nature and properties of the material we’ve excavated at Sandy Ridge to make room for entombing 100,000 tonnes (and counting) of hazardous waste?

Really? Not even once?

Kaolin is a soft white clay that is naturally highly absorbent, with non-swelling properties. Chances are you have something at home with kaolin in it. Kaolin is used in ceramics, medicine, toothpaste, cosmetics, paper coating, paint, rubber, and fibreglass, among many other things. The absorbent nature of kaolin is what makes it ideal for a geological repository, and helps make Sandy Ridge as safe as anywhere on earth for the permanent disposal of hazardous waste.

At Tellus, we like to say that Sandy Ridge is where nature’s fortress meets fail-safe innovation. Kaolin’s role in that fortress is to seal hazardous material cells, preventing leaching.

As if kaolin itself was not versatile enough, turning kaolin into high purity alumina (HPA), aluminium oxide, is an emerging application. HPA is used in the lithium-ion battery sector, meaning kaolin has critical mineral applications.

So, what have we done with our kaolin to date? Well, we currently have a stockpile of 150,000 tonnes, some of which is used today for waste encapsulation, and we expect to excavate another 250,000 tonnes over the next year as we build our second waste cell. We’ve always had plans eventually to commercialise our kaolin, and market conditions over recent months, driven largely by the war in Ukraine—a major global source of kaolin—strengthen this possibility in the near term.

 

But there is a more exciting possibility.

If treated in a kiln, kaolin can produce metakaolin. As an ingredient in so-called “green cement,” metakaolin can reduce the carbon emissions in cement production by up to half. That’s not insignificant when you consider global cement manufacturing produces around eight per cent of global CO2 emissions.

In other words, our enormous kaolin reserve could become another avenue for delivering on our commitment to enable a greener and more sustainable future for this country.