Perlite is a naturally occurring siliceous rock of volcanic origin. This rock when crushed and heated under proper conditions expands to 20 times or more of its original volume. A special milling and classification process gives the correct particle size distributions needed for optimum performance as a filter aid.
Perlite FILTER AID improve filtering efficiency by increasing the permeability of the filter cake and is either added to the suspension to be filtered or built on the filter media as a layer through which the liquid must pass.
The physical character of expanded perlite bubbles lends itself to a variety of special purposes â?? including use as a filter aid separating small solid particles from liquids..
THE BENEFITS OF PERLITE AS A FILTER AID
Perlite FILTER AID are lightweight, inert, impart no taste or odor to liquids being filtered, and are virtually insoluble in mineral and organic acids at all temperatures. Solubility in strong alkaline solutions varies depending on temperature and contact time.
Without using a filter aid the solid particles in the liquid will soon accumulate on filtering surfaces and block them.
A perlite filter aid makes a filtering layer (cake) that transfers the actual filtering from the septum to the whole mass of filter aid. Filtration occurs in the tiny pores formed by the fine particles of filter aid.
Volume-Based Pre-coat Filtration
Perlite FILTER AID provide users with a lightweight material choice. Perlite filter aid grades provide the user with a density advantage from 20 to 50% over other types of FILTER AID. Perlite filter aid dry density ranges from 100 to 200 kg/m3 (6 to 12 lb/ft3), and the filter cake density range is 100 to 270 kg/m3 (7 to 17 lb/ft3). In contrast, other filtration materials produce equal performance filter cakes in the range of 230 to 420 kg/m3 (15 to 25 lb/ft3).