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Diatomite (Diatomaceous Earth)

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For listing of Imerys Diatomite Products click here...

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Properties

Diatomaceous earth is a powder produced from diatomite, a sedimentary rock composed of the skeletal remains of single-cell aquatic plants called diatoms. As one diatom generation is replaced by another over millions of years, the skeletons began to collect on the sea bed and on the bottom of lakes to form diatomite deposits. The remarkably complex skeletons are unusual in that they are composed of natural silica with a high degree of unique structure.

 

 

Diatomite represents a very rare occurrence – a mineral silica that has an elaborate structure worked by nature into a labyrinth of tiny holes. No other silica source that is mined or chemically prepared has such a structure. The key to the exceptional properties of diatomite lies more in the microstructure – each diatom is peppered with thousands of holes, usually of three distinct sizes, ranging from a few microns in diameter down to submicron diameters. The number and sizes of holes vary with the species.

 

The combination of the natural silica composition, the overall structure of the diatom particles, and the network of holes in the structure are responsible for the unique properties of these multi functional mineral products.

 

The Main Markets for Diatomaceous Earth

Diatomaceous earth is dedicated to the purposes of filtration. The relatively inert silica structure with its numerous micropores gives remarkable properties when built into a filter cake for the filtration of liquids. Beer, wine, sugar syrups, fruit juices, antibiotics and industrial chemicals are examples of the number and variety of products that take advantage of the excellent filtering capability of diatomaceous earth for both large and sub-micron particles.

 

The unique structure displays other useful characteristics, making it the best choice in the manufacture of products such as metal polishes, matt paint formulations and match heads. In the latter application, the diatomaceous earth not only provides the frictional resistance to ignite the match head, but also it slows down the rate of ignition sufficiently to allow enough time for the wood to catch alight.

 

World Minerals, part of the Imerys group, not only knows and understands these diverse applications, but modifies its production processes to make grades dedicated to particular applications.

 

For the paint industry the key parameter is the size of the larger particles that protrude through the paint film – for these products, a test is run, especially to control this characteristic.
Diatomite is also used in paper, brick, tile, ceramics, plastics, soaps, detergents and other products as a filler.

 

Diatomite has also found value as an insulating material in high-temperature mechanisms like furnaces and boilers. It has also proven effective as a sound insulator.

 

Geology

The skeletal remains that make up the deposits flourished as diatoms in prehistoric waters across the globe. Most are fossilised, being laid down in the Miocene period, some 15 million years ago, and most are from freshwater sources. The Imerys deposits are numerous, and include the world’s largest worked mine and marine deposit in Lompoc, California. Marine diatom species are more varied than their freshwater cousins, and the profusion of shapes results in an extremely light density diatomaceous earth powder, with excellent filtration characteristics.

 

Quick View
Mineralogy: Natural silica
Particle Size: (µm)	5-100
Typical MOH Hardness:	5 - 6
Specific Gravity:	2.0 - 2.3
Refractive Index:	1.48
Moisture: (max)	0.1 - 9
pH:	6 - 11

 

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