GRANULAR GOETHITE FINE PARTICULATE POWDER, ITS PRODUCTION AND PRODUCTION OF GRANULAR IRON OXIDE FINE PARTICULATE POWDER USING THE SAME FINE PARTICULATE POWDER

• Main Author: KUROKAWA HARUMI
• Format: Patent
• Language: English
• Published: 05.03.1996
• Edition: 6
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; INORGANIC CHEMISTRY; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; THEIR RELEVANT APPARATUS; TRANSPORTING

PURPOSE: To obtain the subject fine particulate powder, excellent in absorptivity for sulfur oxides, nitrogen oxides, H2 S, etc., by selecting a granular goethite fine particulate powder, having a specified value of the BET specific surface area and containing a prescribed amount of a silicon compound therein. CONSTITUTION: A granular goethite fine particulate powder, having 300-350m /g value of BET specific surface area and containing a silicon compound in an amount of 0.5-2.0 atomic % based on the total Fe expressed in terms of Si is selected. Furthermore, this method for producing the fine particulate powder is to preferably react an aqueous solution of a ferrous salt with an aqueous solution of an alkali carbonate in an amount of >1.0 equiv. based on Fe<2+> in the aqueous solution in a nonoxidizing atmosphere, provide a suspension comprising a precipitate containing iron, stir the resultant suspension at 50-65 deg.C in a nonoxidizing atmosphere for 30-360min, then add a water-soluble silicate in an amount of 0.5-5.0 atomic % based on the Fe<2+> in the aqueous solution of the ferrous salt expressed in terms of Si, subsequently pass a gas containing O2 through the solution at 50-60 deg.C, carry out the oxidizing reaction, produce the granular goethite fine particles, separate the particles by filtration, wash the resultant particles with water and dry the washed particles.