Filtration

To produce filtration grades, expanded perlite is milled and classified according to particle size and permeability. During filtration, its lightweight and irregular particles interlock to form a stable, incompressible filter cake containing a network of microscopic passages. This porous structure retains suspended solids while allowing the liquid to flow through.

Different grades provide different balances of clarity, flow rate and solids-holding capacity. Perlite filter aids may be used as a precoat on the filter medium, as a body feed added to the liquid during processing or through a combination of both methods. Correct grade selection helps maintain stable filtration performance as solids accumulate.

Perlite filter aids are suitable for clarifying wine, must, beer, fruit juice and other alcoholic or non-alcoholic beverages. Depending on the product and operating conditions, they can improve filtrate clarity, maintain efficient flow, increase solids-holding capacity and reduce premature blockage of the filter medium.

Efficient cake formation can also reduce filter-aid consumption, limit the amount of valuable liquid retained in the spent cake and support easier cake release during cleaning. These effects can improve product yield and filtration productivity while reducing the volume of material requiring disposal.

Perlite is chemically inert and can be produced with low levels of soluble and extractable impurities. Low soluble-iron content is particularly important in beverage applications, where mineral interactions may affect taste, colour, aroma or product stability.

By combining low bulk density, adjustable permeability and effective solids retention, perlite provides a flexible and cost-efficient filtration medium. The appropriate grade should be selected according to the required clarity, throughput, solids content and filtration equipment.