Where Does Perlite Come From?
A common ingredient in potting soils and a substrate that’s widely used in a range of applications, perlite is often misunderstood. In this article, we’re going to explain the basics about perlite–where it comes from, how it’s processed, and how it gets to the consumer.
What Is Perlite?
While it may look like tiny pieces of popcorn, perlite is actually expanded volcanic glass. Obsidian is a black-colored extrusive igneous rock, meaning that it is made from magma that erupted out of a volcano. When obsidian forms close to the Earth’s surface, it can cool so quickly that crystals do not form, creating a material that is closer to glass than what we typically think of as rock. Some experts feel that this cooled magma may have an innate charge that attracts water. As obsidian eventually draws in anywhere from 2-5% water content from the surrounding environment over time, it changes from a dark, glassy substance to crude perlite, which is naturally gray or glossy black.
Where Does Perlite Come From?
We know that perlite originates from obsidian, but where are the obsidian deposits located? And how is the eventual perlite harvested?
Obsidian is found anywhere in the world that has historically seen volcanic activity. Therefore, perlite, as a natural adaptation of obsidian and water, is also found in areas with ancient volcanic activity. These hotspots occur all around the world, with large deposits found on every continent. In fact, the United States is a top producer (and consumer) of both crude and expanded perlite, with western states like New Mexico, California, and Oregon being the main domestic producers. While volcanoes still erupt in modern times, the perlite harvested today is not new. It takes thousands of years for obsidian, and thus perlite, to form.
How Is Perlite Harvested?
The harvesting or extracting of perlite is done through open-pit surface mining. This is a specific mining technique where a large pit is dug to extract mineral deposits that are near the surface but may not be in a strictly horizontal layer. Heavy machinery is used to “rip” through the deposit, or blasting is done if ripping isn’t well suited to the location or the crude perlite’s structure isn’t ideal. Blasting involves drilling holes into the perlite layer and using explosives to blast it free, breaking the crude perlite into more manageable chunks. Once crude perlite is extracted from the ground, it is then crushed, screened, sized, and then loaded on trucks or covered hopper rail cars for transport to expansion plants, where it is then heated and expanded.
Once crude perlite is mined and transported, it is then superheated in vertical kilns to 1600 ℉ (871 ℃) or higher, causing the trapped water to quickly vaporize into steam and leading the perlite to rapidly expand. Perlite can actually expand to as much as 7 to 20 times its original size. Where there once was water, there is now air, and perlite becomes a light gray to white, lightweight, highly porous material. Perlite producers can play with factors like initial particle size, heat intensity, preheat level, air flow, and furnace time in order to create different sizes, densities or grades (micron, super fine, fine, medium, coarse, and super coarse, along with customizable blends thereof) as their end product.
Domestic perlite mining is typically done in remote areas. Any ore not suitable for processing and sale can be used to reclaim the mined area, so there is little waste involved with perlite mining. There is very little runoff involved with perlite processing.
Perlite is highly sustainable, having been mined for nearly 60 years and having consumed less than 1% of the known reserves worldwide. Perlite has many characteristics that negate the carbon impact of processing through being a permanent ingredient in providing a balance of aeration and water retention, to its unique insulating and environmentally beneficial applications and uses, like cleaning our air, water, and environmental wastes in industrial operations.
How Perlite Gets To The Consumer
Starting life millennia ago in a volcano, obsidian and then perlite undergo a lot of applied heat to get to be the product used by consumers today. After the mining, processing, and expansion work is done, perlite is once again sifted through various sizes of screens and sorted into grades (micron, super fine, fine, medium, coarse, and super coarse, along with customizable blends thereof) that are used for different applications across industries. Once sorted, perlite is put into bags, boxes, and bulk containers of all sizes and quantities, depending on the end receiver. Because it’s so lightweight, perlite is easy to ship across the country or even across the world. Whatever the intended use, perlite is equally available for corporations and consumers alike.
Your Local Source For High Quality Perlite
Perlite Vermiculite Packaging (PVP) Industries, Inc. has been the only Northeast Ohio, Cleveland area processor and producer of perlite for the horticultural, construction, industrial, and even more unique or niche markets for four decades. We are dedicated to quality and safety, and are proud to offer products that boast improved results in a wide range of projects. Check out our FAQ page for more information about our products, and feel free to contact us with any questions about perlite, and to find a distributor.