How Perlite Is Made

The versatility of perlite can be understood better when we dive into specific product forms it can take and their applications in various industries. Here’s a breakdown:

Raw perlite

At The Mine

Topsoil and organic matter are removed from the surface and stockpiled for post mining reclamation.

Areas to be mined are mapped and drill holes sampled for quality testing.

The crude ore is extracted with excavation equipment according to an open pit mine plan.

Perlite ore is crushed to an initial uniform size at the quarry site and then hauled by truck to the processing plant either located on site close by, or in another location.

Expanded Perlite

At The Processing Location

Perlite ore is further reduced in size and sent through a rotary kiln dryer at 120 – 175°C (200 – 350°F) to drive off “free” moisture on the exterior of each particle.

The drying process is carefully controlled to keep from overheating the ore and driving off the “combined” moisture which allows the perlite to expand when heated to final temperature.

The crushed ore is processed through a series of screens with successively smaller openings, sorting it into various grades and sizes.

The ore may then be blended to meet customer specifications and/or loaded onto trucks or rail cars for delivery.

Delivery vehicles are inspected prior to loading to ensure they are clean, dry and contamination free.

A loading sample is tested to confirm specifications.

No processing or formulation aids are added to the perlite ore in this process. All products are 100% natural perlite.

Perlite Microspheres

At The Expansion Facility

Ore is transported in bulk or 1 ton super sacks by truck, rail or ocean-going vessels to the expansion location.

Oftentimes this is a dedicated regional expander specializing in manufacturing expanded perlite products. (In the case of cryogenic perlite, it may located at a job site where a mobile expansion unit will be used to produce the finished product.)

Ore received is inspected for size, quality, consistency, and purity.

The ore is stored in large silos or bulk storage bins to protect from moisture or contamination.

The ore is then fed into the furnace at a controlled rate via a bulk hopper, conveyor, and bucket elevator system. Various grades or sizes may be combined at this stage to achieve the desired final particle size gradation.

For larger particle sizes especially, preheat may be added to soften the particles prior to exposure to to the full heat of the furnace.

Perlite furnaces are orientated vertically to facilitate sorting of the particles at different stages of expansion.

The ore particles are fed into the furnace mid-way up the furnace barrel and levitate in a powerful stream of forced hot air heated to 900-1,000°C (1,800-2,000°F) by a combination burner and blower fixture at the base. Once fully expanded, the particles are light enough to be pulled out of the top of the stack by a fan system at the top which also sends the particles to cooling.

It is this delicate balance between opposing forces of gravity, positive forced air and rising heat, and negative suction at the top which makes expanding perlite as much an art as an exercise in precise engineering.

Finally, the newly expanded perlite particles undergo air cyclone classification (cooling and sorting), then pass over a series of screens that further sort them into their finish grades.

At times, only a single product is made at a time, whereas at other times, multiple products can come from the same stream.

Finished products are sampled and tested for conformance to specifications (particle size distribution and density mainly).

The sorted particles are then feed into various filling systems for packaging in bags, bulk bags, automatic filling and palletizing systems, or bulk storage and loadout systems.

It takes a combination of scientific and engineering know-how, and a skilled and trained workforce to produce consistent products from a continuous product stream as efficiently as possible. Production staff are trained in sampling, and analyzing outputs to ensure standards for quality and specifications are met while minimizing waste and using energy efficiently.

Perlite Filter Aid

Perlite Filter Aid

Industry: Food and Beverage, Pharmaceuticals

Use-case: Acts as a natural filter in the processing of liquids, including beer, wine, and certain pharmaceutical products

Why Effective: The porous nature of Perlite captures impurities, making it an ideal choice for filtration and filter aids without introducing chemicals or affecting the taste and quality of the product.

Perlite as a lightweight aggregate

Perlite as a Lightweight Aggregate

Industry: Construction

Use-case: Used in concrete, plasters, and other building materials to reduce weight while maintaining strength.

Why Effective: Its lightweight nature, as in Perlite for construction, means less overall weight, which can be crucial in projects like bridges or high-rise buildings.

Horticulture Perlite

Horticulture Perlite

Industry: Agriculture, Gardening

Use-case: As a soil amendment, it ensures good aeration, retains water, and promotes root growth.

Why Effective:  The porous nature of horticultural Perlite, also known as horticulture perlite, ensures balanced moisture retention, while its sterility prevents the introduction of pests or diseases.

perlite absorbent

Perlite as a Absorbent

Industry: Cryogenics

Use-case: As an insulator for extremely low-temperature storage tanks like those for liquid nitrogen or oxygen.

Why Effective:  Its low thermal conductivity, along with its use as a perlite absorbent, ensures minimal heat exchange, which is vital for maintaining low temperatures in cryogenic storage.

Perlite cryogenic solutions

Cryogenic Perlite

Industry: Cryogenics

Use-case: As an insulator for extremely low-temperature storage tanks like those for liquid nitrogen or oxygen.

Why Effective: Its low thermal conductivity is essential for cryogenic and cryogenic industrial solutions, ensuring minimal heat exchange and maintaining low temperatures in cryogenic storage.

Perlite in Stormwater management

Perlite in Stormwater Management

Industry: Urban Development, Environmental Planning

Use-case: Used in rain gardens and other green infrastructures for water filtration and retention.

Why Effective:  It helps filter pollutants and slow down stormwater runoff, assists in management and maintenance, and provides effective stormwater runoff solutions in urban areas.

Perlite Baghouse Precoat

Perlite Baghouse Precoat

Industry: Industrial Processing

Use-case: Used as a precoat for baghouses (a system for filtering particulate matter from industrial exhaust gases).

Why Effective: Enhances the efficiency of the filtration process by preventing the clogging of filter bags.

expanded perlite

In Summary

By understanding the specific product forms and their applications, industries can better determine which form of perlite suits their needs best. Whether as a foundational raw material, a lightweight aggregate, or a natural filter, perlite’s adaptability makes it invaluable across sectors.