All Celatom® diatomaceous earth filter aids are of the freshwater type andarepredominantly (85%-95%) of the species Melosira Granulata. This species is characterized by a natural, filter-like, cylindrical shape of great mechanical strength. During the late Tertiary Period (approximately 5 million to 20 million years ago), massive deposits of diatoms were formed in the freshwater lakes which covered much of what is now Nevada and eastern Oregon. Geological upheavals over the eons have exposed these large and high-purity deposits in a very few places where they were protected by a cap of volcanic ash and preserved from erosion. These deposits can be as much as several hundred feet thick or as little as a few inches, depending on the climate in which they lived.
Diatoms grow differently than most plants. Most plants utilize solar energy to synthesize cellulose for their cell walls, but a diatom extracts dissolved amorphous silica from the water building a strong, pure, and stable skeleton called a frustule. These naturally porous silica structures are ideal for applications demanding performance and purity, such brewing, food and beverage, and pharmaceutical applications.
Where does DE come from?
Celatom® diatomite is surface-mined from our deposits located in Nevada and Oregon. The purity and consistency of our ore deposits allow us to supply customers with identical products from any of our processing plants, which ensures consistent and reliable performance.
How is diatomite ore processed into commercial DE products?
The production of diatomite products is difficult and complex. It requires large processing facilities and heavy earth-moving equipment. EP Minerals operates four facilities for the production of diatomite products, three in Nevada and one in eastern Oregon.
The ore is first surface-mined. To access the ore, a considerable quantity of earth may have to removed, known as overburden. When this layer is removed and the purest diatomite strata are exposed, the diatomite is then carefully dug from the bed with hydraulic excavators resembling large backhoes, which allows selective removal of the diatomite while rejecting darker layers with too much volcanic ash or other impurities. The diatomite is then arranged into stockpiles where solar energy helps dry it before processing.
The stockpiled material is hauled to the processing plant where it is off-loaded into an automated crusher and conveying unit. The crushed ore is elevated to storage bins of sufficient capacity to feed the plant for nearly continuous processing, 7 days a week, 24 hours a day.
The ore in the storage bins still contains 20-30% moisture; significant amounts of heat must be applied to dry the product further. The ore is then milled gently to preserve the structure of the diatoms which give Celatom® DE its remarkable properties. To provide the quality that our customers expect, it is critical that the ore be completely pure. A small amount of foreign matter can greatly downgrade the product performance. These impurities are removed via a series of separators and traps.
To make calcined DE filter aids, the ore is classified and sent to a large rotary kiln, where it is calcined (heated) to agglomerate the diatoms and produce the desired grade. This is a highly energy-intensive process. After calcination, the DE is light pink in color. A fluxing agent is sometimes added to the kiln in order to agglomerate the diatoms even further to achieve the high flow rates of our fast white grades. After calcination, the product is milled and classified again before it is packaged and delivered to our customers.