Slurries such as organic salts, pectin, or liquid sulfur are turned into solids before further processing. Pressure leaf filters separate the impurities and form the material into a cake.

The liquid or semi-liquid is pumped into a vessel lined with a series of filters of varying mesh sizes. The impurities are let through, leaving behind a purified substance. In case of hazardous chemicals, the filtration technology sluices the material off the leaves by spraying water and pumping out the discharge. The filtration equipment can be configured either vertically or horizontally.