Perlite

Properties of Perlite

• Perlite softens at 850–900°C.
• Water vaporizes causing the material to expand 7–16 times.
• Expanded perlite is white due to trapped bubbles.
• Raw perlite has a bulk density of 1100kg/m³.
• Expanded perlite has a bulk density of 30–150kg/m³.

Chemical Composition and Formation of Perlite

• Typical analysis: 70–75% silicon dioxide, 12–15% aluminium oxide, 3–4% sodium oxide, 3–5% potassium oxide, 0.5-2% iron oxide.
• No crystalline structure.
• Formation process: volcanic activity, high temperature, rapid cooling, expansion, lightweight, and porous properties.

Sources, Production, and Industrial Applications

• Estimated world reserves of perlite: 700 million tonnes.
• Armenia reserves: 150 million m³, Other reserves: Greece – 120 million tonnes, Turkey, USA, and Hungary – 49-57 million tonnes.
• Global production in 2018: 4.6 million tonnes.
• Leading producers: China, Turkey, Greece, USA, Armenia, and Hungary.
• Industrial applications: construction industry, horticulture, filtration, insulation, cryogenic insulation.

Uses and Substitutes of Perlite

• Commercial applications due to low density and price.
• Construction applications like lightweight plasters and concrete.
• Aquatic filtration in pools.
• Biotechnological applications for enzyme immobilization.
• Agricultural uses for soil amendment and hydroponics.
• Substitutes: diatomite for filter-aids, expanded clay for building materials, shale, pumice, slag, vermiculite.

Occupational Safety and External Links

• Perlite contains silicon dioxide.
• Goggles and silica filtering masks are recommended.
• OSHA and NIOSH have exposure limits for perlite.
• External links: Wikimedia Commons, The Perlite Institute, Mineral Information Institute, Popular Mechanics, That Wonderful Volcanic Popcorn.

Perlite Data Sources