The production of expanded perlite is a two-stage process. The ore is firstly mined, pre-crushed, ground and graded in the processing plant, which is usually located nearby to the mine site or to the loading/shipping point. The output of such plants is a series of co-produced perlite grades (having grain sizes between 3,5 mm and 0,075 mm. Sized perlite grades are then transported either bulk or in big-bags to the expansion plants hundreds or even thousands of kilometers away to expansion plants. There, sized unexpanded perlite grains are fed in vertical furnaces where they are expanded to form lightweight perlite cellular bubbles. This special granular lightweight product is afterwards mechanically (e.g. through dry or wet mixing) or otherwise incorporated into the various end-products.
Typical Applications of Perlite
1. Construction applications (Thermal-acoustical insulation ceiling tiles, Lightweight concrete, plasters and mortars, Loose fill insulation in cavity walls, etc.)
2. Horticulture applications (Hydroponic cultivation, Growing Media mixed with sand and peat (sphagnum moss)
3. Food and chemical industry (Filter-Aids, Phosphoric Acid production for Fertilizers)
4. “Super-insulating” material (Cryogenics and Low Temperature insulation, Alkali Silicate bonded preformed products, Calcium silicate preformed products,
5. There are various other less important applications, like “topping” in Steel and Foundry industries, high performance micro-fillers for coatings, pozzolan and superpozzolan, abrasive in soaps, cleaners, and polishes, in textile processing industry as fabric ageing material, etc. These latter applications account for less than 5 % of the total perlite market by volume and value.