Procedure to produce a filtering material. (Machine-translation by Google Translate, not legally binding)

摘要

Process for producing a filter material, characterized by the fact of expanding a pearlitic mineral to give a multicellular product having a mass density of about 1-6 lb/cubic foot (approximately 0.016-0.096 kg/dm-3), and preparing from the product a fragmentary material whose particles are less than 149 microns, having, at least 80% by volume of the fragmentary material, the property of substantially complete sedimentation in water and be substantially deprived of closed or partially closed voids. (Machine-translation by Google Translate, not legally binding)