The Perlite Institute claims that perlite, a volcanic glass, is "the world's most versatile mineral".

Perlite is sold and used in four forms: ore, expanded into aggregate (big particles), filter aid (milled aggregate), and microballoons.

The public is most familiar with perlite aggregate. Perlite aggregate is used loose as insulation in the outside walls of buildings and cryogenic tanks. The tremendous insulation value is also useful in fireproof coatings on steel structural beams, in wallboard, and in chimney coatings.

Plant nurseries and hydroponic farms view perlite aggregate as an essential part of their daily operations to propagate and grow their plants.

Perlite filter aid is used to process liquids such as beet sugar, beer, wine, water, antibiotics, and edible oils.

The top three uses for perlite microballoons are: Tape Joint Compounds and other putties, explosives, and cultured marble. All three uses take advantage of the fact that these microballoons are simply "packaged air". In a tape joint compound, shrinkage upon drying is cut in half, allowing the user to put two coats on instead of three.

Ore can be used as a filler or to make one or more of the above types of materials.

So, how does this volcanic glass turn into such a variety of products?

Perlite is a relatively young form of a rock. It begins to form when a lava flow cools too quickly to allow crystals to form. This cooled volcanic glass traps some water. More water may then be added to the glass over time from ground water intrusion. This additional water tends to fracture the perlite, creating the unique "onion skin" character.

Therefore, most perlite ore is soft or brittle enough to be mined without the use of blasting. The ore is brought to a processing plant, crushed, dried slightly, and then sized or crushed again for further size separations.

Perlite contains about 3 to 5 percent water. This water turns to steam and "pops", or expands, the ore particle when the temperature is quickly raised to the glass transition temperature (about 1800 degrees F). It turns out that different mines produce ore with different expansion properties, as well as different colors and impurity levels. As a result, many expansion facilities use multiple grades of ore from several suppliers.

American Stone Pioneers' products are made from different ore grades from different sources. Additionally, our products are the purest available today, since non-perlitic grit has been removed. This reduces abrasion of equipment for filtration users, and improves the color of our microballoons and, improves the insulation value of our aggregates.

Contact us today to see how we can be of assistance to your company.


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American Stone Pioneers
P.O. Box 4083
Rolling Hills Estates, CA 90274
Phone: 310-377-7977  Fax: 310-377-1287