Moulding of Tubular Filter Elements Based on Coarse Particles of Silicates and Aluminosilicates

摘要

Liquid filtration application of tubular filter elements with length more than 500 mm and diameter up to 65 mm using coarse particles (200 - 100 um) based on silicates and aluminosilicates as starting materials is perspective. Brittleness of these materials and irregular (aluminosilicates) or close to spherical (silicates) shape of particles with smooth surface does not allow molding them into porous coherent bodies without special feedstock preparation. Under consideration of the physicochemical mechanics the requirements for moulding composition for radial pressing of long tubular blanks have been formulated. Formulations of moulding compositions with solid phase concentration of 75 to 60 wt. % have been developed, including organic porophores, liquid ligaments, plasticizers, and surfactants. Moulding compositions are classified as non-Newtonian fluids that change the Theological properties, particularly effective viscosity, under the influence of compaction pressure. Areas of linear change of effective viscosity have been identified and acceptable ranges of pressure for plastic deformation of feedstock without destroying pressings have been defined. The technology of obtaining tubular filter elements based on silicates and aluminosilicates has been developed.