Perlite: The Versatile Mineral
You know those little white rocks you see in soil and potting mixtures? That’s perlite! As a growing medium, its benefits include improved aeration, water retention and drainage, but perlite’s uses go far beyond gardening. This non-decaying additive is used to aerate any medium with which it is mixed—and this includes cement, loose-fill insulation, and masonry construction. Perlite can even be used to filter the water in swimming pools, as an abrasive in various products, and for a host of other functions in a wide variety of applications from consumer-based products to industrial uses.
But what is perlite and what are the properties that make it so versatile?
What Exactly Is Perlite?
Perlite is a naturally occurring glassy volcanic rock that forms when lava is submerged in water and cools so quickly that the water is trapped in the glass. When heated at extreme temperatures, it pops like popcorn and expands up to 16 times in volume, producing a product that is so lightweight it is up to 20 times less dense after popping than in its original state. This ability to expand and still maintain a low-weight density is just one of the many reasons why perlite is so versatile.
Perlite’s versatility is due to its unique characteristics:
The Many Uses of Perlite
When the water content of perlite is released through extreme heat, expanding the particles, the structure of those particles presents many microscopic pathways that provide air- and water-holding properties that are useful in many industrial and business applications. The size and grade of expanded perlite determine its use in most cases. Exceptions to this are air filtration, liquid filtration, fillers, and abrasives.
Some of the uses for expanded perlite include:
Ambient and Low-Temperature Insulation: Perlite is used in refrigeration plants, wall insulation, in the manufacture of portable coolers and ice boxes, as core filler in wallboards, and in roof decking, concrete blocks, and concrete floor fill.
High-Temperature Insulation: Perlite is used in foundry cores and in molds and ovens or as a crucible topping.
Medium- to High-Temperature Insulation: Perlite is used as a pipe-covering in coaxial tubing, pour-in pipe insulation, compression moldings, and in hard-setting compositions.
Cryogenics: Perlite helps contain super-cooled gases used in stationary industrial plants and in containers for transport.
Oil-Well Treatments: Granules are an inexpensive additive used in low-density water- and mud-based drilling, and for oil-well cementing.
Fireproofing: Fireproof, inert and inorganic, perlite is used in fire insulation for chimney linings and fireproof rooms, doors, and safes.
Acoustic Applications: Perlite’s unique sound-absorbing properties are ideal for use in plaster boards, ceiling tiles, plasters and mortars, and in walls constructed to absorb highway sounds.
Horticultural Applications: Perlite is used as a seed-starting and growing medium, a soil conditioner and seed coating, and in growing hydroponic gardens and developing green-roof solutions.
Lightweight Aggregate Construction: Perlite is useful in non-load-bearing fill, as a coating for tunnel walls and pipes, for bricks and tiles, for pottery and refractories, and in lightweight aggregate concrete.
Absorption: Perlite’s unique absorption properties lend it to be used for pollution control and to clean up environmental accidents such as oil spills. In this way it can also be used for pelletized seed and as a carrier of agricultural chemicals in pesticides and herbicides.
Agricultural Additives: As a poultry and pet litter supplement, perlite reduces odor and absorbs moisture for a healthier environment. It is also widely used in animal feed to prevent caking and as a carrier for nutrients and medicines for veterinary use.
After expansion, perlite can be further processed by milling and classifying to create a superior filter medium.
Air Filtration: Perlite is often used as a pre-coat for baghouse dust collectors that keep solid and dust particles from entering a place of work.
Liquid Filtration: Perlite can be used to filter comestibles such as beer, wine, sugar, juice, edible oils, and citric acid. It is also used as a filter in the creation of pharmaceuticals, and as an element in processing items such as biodiesel, storm water runoff, and potable water.
If the application calls for smaller particles or if the production process uses moisture, our superfine Sil-Cell® can be used.
Fillers: Perlite’s lightweight and shock-absorbing properties make it the perfect packing material for shipping and as filler for paints, plastics, explosives, and caulking.
Abrasives: Perlite is used as an abrasive in polishes, dental compounds, soaps, cleaners, and more.
The Proud Experts On Perlite
At Silbrico we’ve been exploring and perfecting the many possible uses of expanded perlite for decades. This year we are celebrating our 75th anniversary! We’re proud to be part of this industry that not only serves so many, but is environmentally friendly as well.
The mining for perlite is all done above-ground using an open-pit method with a bulldozer and, when needed, blasting. It’s safer and sustainable with less than 1% of the earth’s perlite mined to date. In addition, our colleagues at the Perlite Institute, a worldwide association of perlite professionals, conducted a series of tests that determined that perlite doesn’t pose any significant respiratory risk and is a safe product.
To learn more about the power and possibilities of perlite, check out the Perlite 101 and Uses pages on our website.