PATENTS

USA 6,110,528., Patented Aug. 29, 2000

METHOD FOR THE PREPARATION OF FINE HOLLOW GLASS SPHERES COATED WITH TITANIUM OXIDE

ABSTRACT: Disclosed is a method for preparation of fine hollow glass spheres coated with titanium dioxide from particles of a volcanic vitreous deposit sand occurring in nature. The method comprises the steps of: (a) dispersing the starting particles in an aqueous medium containing hydrogen chloride (or sulfuric acid) and titanium chloride (or titanium sulfate); (b) admixing the aqueous dispersion of the particles with an aqueous alkaline solution such as a solution of ammonium hydrogencarbonate to effect hydrolysis of the titanium chloride (or sulfate) into hydrous titanium oxide forming a coating layer on the particles; and (c) subjecting the particles coated with hydrous titanium oxide to a heat treatment for expansion of the vitreous particles into hollow glass spheres with simultaneous conversion of the hydrous titanium oxide into titanium dioxide forming a coating layer on the hollow glass spheres.

USA 5,833,728., Patented Nov. 10, 1998

METHOD FOR THE PREPARATION OF VITREOUS HOLLOW MICROSPHERES

ABSTRACT: Provided is a method for the efficient preparation of fine hollow spherical glassy bodies having a high strength and excellent whiteness from a volcanic vitreous deposit as the starting material. The fine hollow spherical glassy bodies as desired can be prepared by dispersing 100 parts by weight og a powder of a volcanic vitreous deposit in an aqueous solution containing 1 to 10 parts by weight of aluminum sulfate, adding an aqueous alkaline solution to this liquid suspension to cause deposition of alumina hydrate onto the surface of the particles of said powder and washing and drying of the solid material followed by a heat treatment for 1 second to 1 minute at a temperature of 900° to 1100°C.

USA 5,614,255., Patented Mar. 25, 1997

METHOD FOR THE PREPARATION OF VITREOUS HOLLOW MICROSPHERES

ABSTRACT: Proposed is an efficient method for the preparation of vitreous hollow microspheres from particles of a vitreous volcanic deposit by a heat treatment to effect expansion of the particles by foaming. The inventive method comprises a step, prior to the heat treatment for expansion of the particles, in which the starting particles are dispersed in an aqueous medium containing aluminum sulfate and urea each in a specified concentration followed by heating treatment of the dispersion so as to deposit a coating layer of aluninum hydroxide on the particles surface so that the efficiency of foaming can be greatly improved without the disadvantage of particles agglomeration.

USA 5,017,523., Patented May 21, 1991

METHOD FOR THE PREPARATION OF ULTRA-FINE HOLLOW GLASS SPHERES

ABSTRACT: Ultra-fine hollow glass spheres suitable as a filler in light-weight composite materials for building use and the like can be prepared from a fine powder of volcanic glass even when the starting powder has a particle size as fine as 20 micron meter or smaller. The inventive method comprises an acid-leaching treatment of the atarting powder using hydrochloric or sulfuric acid under hydrothermal conditions at 150°-200°C. to modify the chemical composition in the surface layer of the particles and a subsequent heat treatment of the acid-treated particles at a water vapar produced from the structural water in the softened particles. By virtur of modified composition in the surface layer and in contrast to the prior art method without the acid treatment, a good balance can be obtained between the rate of water vapor release and softening of the particles even when the particles size is extremely small to facilitate expansion of the particles.

USA 3,904,377., Patented Sept. 9, 1975

LIGHTWEIGHT COMPOSITE CONTAINING HOLLOW GLASS MICROSPHERES

ABSTRACT: When finery divided SHIRASU (pumice ejected from volcanoes and the secondary deposit of such pumice) is roasted at a temperature in the range of from about 800°C to about 1200°C, the vitreous particles contained in said SHIRASU foam and consequently produce light-weight hollow glass microspheres. The hollow glass microspheres so produced are superior to conventional glass micro-spheres especially in their resistance to heat and can therefore be combined with metal, carbon, as well as with cement and other materials to produce novel lightweight composites.

USA 3,847,806., Patented Nov. 12,1974

METHOD FOR TRETING SLUDGE FORMED IN CITY SEWAGE SYSTEMS

ABSTRACT: This invention relates to a method for effectively treating sludge formed in city sewer systems. More particularly, this invention relates to a method for obtaining lightweight foamed materials useful as fillers which comprises adding, on filtration of sludge formed in the purification treatment of city sewers, foaming granular volcanic ash deposits to the sludge to facilitate the filtration treatment and utilizing the filtration residue as a lightweight foamed material.

USA 3,752,685., Patented Aug. 14, 1973

METHOD FOR PRODUCING HOLLOW GLASS MICRO-SPHERES AND THEIR COMPOSITES

ABSTRACT: When finely divided Shirasu (pumice ejected from volcanoes and the secondary deposit of such pumice) is roasted at a temperature in the range of from about 800°C., to about 1200°C., the vitreous particles contained in said Shirasu foam and consequently produce light-weight hollow glass micro-spheres. The hollow glass micro-spheres so produced are superior to conventional glass micro-spheres especially in their resistance to heat and can therefore be combined with metal, carbon, as well as with cement and other materials to produce novel light-weight composites.