PRODUCTION OF LIGHT-WEIGHT BUILDING MATERIALS FROM ALUMINIUM HYDROXIDE SLUDGE

摘要

The invention provides a novel light-weight building material suitable for heat and sound insulation from an aluminum hydroxide sludge, which is a very noxious industrial waste material, and disintegrated scrapped paper as the base components. The sludge is first alkalized by the addition of sodium hydroxide to dissolve the gel-like aluminum hydroxide in the form of sodium aluminate and then admixed with the disintegrated scrapped paper to give a slurried mixture which is next neutralized to a weakly acidic condition by adding phosphoric acid whereby insoluble phosphates are deposited on the cellulosic fibers. The slurried mixture is further admixed with a coagulating agent to give a coagulated mass of the fibrous material with deposition of the phosphates. The coagulated mass is then separated from the liquid portion and dried to give a light-weight mass which is used as a blow-on insulating material for buildings or as a material for shaping an insulating board or slab.