Pearlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently.
Pearlite is a mixture of ferrite and cementite forming distinct layers or bands in slowly cooled carbon steels. It is an iron alloy that contains around 88% ferrite and 12% cementite. Pearlite is a non-renewable resource. The world reserves of pearlite are estimated at 700 million tonnes.
During the slow cooling process of an iron-carbon alloy, pearlite forms by a eutectoid reaction as austenite cool down below 723 °C. Pearlite is a microstructure occurring in many common grades of steel. The process makes pearlite one of the strongest structural bulk materials on earth.
This naturally occurring volcanic glass is heated to create lightweight, white, and porous material. It can be used as insulation material and in the construction industry. The best part about it is that it is environmentally friendly and sustainable.
It’s often used as an insulator in homes because it can absorb up to 30% of its weight in water without feeling wet. This makes it perfect for use on the roof or walls of your home, where it will help keep things cool during the summers.
It’s used in gardening as an excellent soil amendment for plans because it provides air pockets for roots to grow into. This means your plants will have better drainage and less water retention than they would with other materials like peat moss or vermiculite.
Pearlite is also used in commercial pool filtration technology, as a replacement for diatomaceous earth filters. It is an excellent filtration aid and is used extensively as an alternative to diatomaceous earth. The popularity of perlite usage as a filter medium is growing considerably worldwide.
Due to thermal and mechanical stability, non-toxicity, and high resistance against microbial attacks and organic solvents, pearlite is widely used in biotechnological applications. It is found to be an excellent support for the immobilization of biocatalysts such as enzymes for bioremediation and sensing applications.
Some of the issues with pearlite are that the water can drain away quickly, being so lightweight pearlite can be blown away and tends to float in excess water, it is a nonrenewable resource, and pearlite dust can create respiratory problems and eye irritation.