Diatomaceous earth
Diatomaceous earth is a substance consisiting primarily of the fossilized remains of diatoms. It's typical chemical composition is 86% silicon, 5% sodium, 3% magnesium, and 2% iron. Diatomaceous earth is also commonly referred to as: diatomaceous silica, diatomite, DE, Kieselgur (in Europe), and fossil shell flour.
Properties
- highly absorbent / drying
- as a material it is relatively light compared to its volume
- its grains are very small and can have sharp edges
Geology
Because diatomaceous earth forms from the fossilized remains of water-borne diatoms, it is found in proximity to either current or former bodies of water. Diatomaceous earth is generally divided into two categories based upon source: freshwater and saltwater. Freshwater diatomaceous earth is mined from dry lakebeds and is characteristically low in crystaline silica content. Saltwater diatomaceous earth, in contrast, contains a high crystalline silica content making it a useful material for filters due to the sieve-like features of the crystals.
Safety Considerations
The absorbent qualities of diatomaceous earth can result in a significant drying of the hands if handled without gloves. The saltwater form contains the highly crystaline form of silica resulting in sharp edges. The sharpness of this version of the material makes it dangerous to breathe and a dust mask is recommended when working with it.
Commercial Applications
The properties of diatomaceous earth make it an appealing material to use in a number of commercial applications. As an insecticide, it can be used to protect both plants and pets via topical application. It also functions well at controlling parasites in both animals and humans when taken internally. Its absorbent qualities make it useful for spill cleanup and the U.S. Center for Disease Control recommends it to clean up toxic liquid spills.
More recently, diatomaceous earth has been employed as a primary ingredient in a type of cat litter. The type of silica used in cat litter comes from freshwater sources and does not pose a significant health risk to pets or humans.
Distributors supply diatomaceous earth in both liquid and powder form.
