# US 4,399,119 A · Manufacture of spherical alumina from gibbsite > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,119 A - Document ID: US4399119A - Status: Granted - Kind: A - Application number: 06/252,654 - Filed: 1981-04-09 - Granted: 1983-08-16 - Earliest claimed: 1980-09-29 - Assignees: Nikki-Universal Co., Ltd. - Inventors: Shizuo Takumi; Toshio Hashimoto; Masaru Tatsushima - Web page: https://patentgrep.com/patent/US4399119A ## CPC - C01F 7/02: Aluminium oxide; Aluminium hydroxide; Aluminates - C01P 2004/32: Spheres - C01P 2006/22: Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability - C01F: COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides or polysulfides of magnesium, calcium, strontium, or barium C01B17/42; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia or cyanogen containing nitrogen and non-metals and optionally metals C01B21/082; amides or imides of silicon C01B21/087}; metal {imides or} amides C01B21/092, {C01B21/0923}; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20; {double sulfates of magnesium with sodium or potassium C01D5/12; with other alkali metals C01D15/00, C01D17/00}) - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract A method of manufacturing spherical alumina particles which comprises the steps of digesting, at an elevated temperature and an elevated pressure, gibbsite with an aqueous hydrochloric acid solution and then forming an aqueous basic aluminum chloride solution; adding, at an elevated temperature, an aqueous ammonia to said aqueous basic aluminum chloride solution to form an alumina hydrosol containing ammonium chloride; commingling said alumina hydrosol with a gelling agent; thereafter dispersing droplets of said mixture in a suspending medium under conditions effective to transform said droplets into hydrogel particles; ageing said hydrogel particles first in said suspending medium and then in aqueous ammonia; and then washing said hydrogel particles with water, drying and calcining to obtain spherical alumina particles. ## Claims ### Claim 1 A method of manufacturing spherical alumina particles comprising the steps of: (a) digesting, at an elevated temperature and an elevated pressure, gibbsite with an aqueous hydrochloric acid solution to thereby form an aqueous basic aluminum chloride solution having an aluminum concentration in the range of from 9 wt.% to 11 wt.% and a weight ratio of aluminum to chloride in the range of from 0.4 to 0.6; (b) adding, at an elevated temperature, an aqueous ammonia solution to said aqueous basic aluminum chloride solution under conditions effective to form an alumina hydrosol containing ammonium chloride, said alumina hydrosol having an aluminum concentration in the range of from 7 wt.% to 10 wt.% and a weight ratio of aluminum to chloride in the range of from 0.6 to 1.3, wherein said weight ratio of aluminum to chloride is calculated on the basis of excluding the chlorine content of said ammonium chloride; (c) then commingling said alumina hydrosol with a gelling agent which hydrolyzes at an elevated temperature thereby forming a mixture, and then dispersing droplets of said mixture in a suspending medium under conditions effective to transform said droplets into hydrogel particles; and (d) ageing said hydrogel particles first in said suspending medium and then in aqueous ammonia, and thereafter washing said hydrogel particles with water, then drying and calcining said hydrogel particles to obtain said spherical alumina particles. ### Claim 2 (depends on 1) A method according to claim 1 in which digestion of gibbsite in the step (a) is carried out at a temperature in the range of from 160.degree. C. to 200.degree. C. and at a pressure in the range of from 4 Kg/cm.sup.2 to 10 Kg/cm.sup.2. ### Claim 3 (depends on 1) A method according to claim 1 in which step (b) is carried out at a temperature in the range of from 80.degree. C. to 105.degree. C. ### Claim 4 (depends on 1) A method according to claim 1 in which said gelling agent used in step (c) comprises hexamethylenetetramine and urea. ### Claim 5 A method of manufacturing spherical alumina comprising the steps of: (a) digesting, at an elevated temperature and an elevated pressure, gibbsite with an aqueous hydrochloric acid solution to thereby form an aqueous basic aluminum chloride solution having an aluminum concentration in the range of from 9 wt.% to 11 wt.% and a weight ratio of aluminum to chloride in the range of from 0.4 to 0.6; (b) adding, at an elevated temperature, an aqueous ammonia solution to said aqueous basic aluminum chloride solution, and then dissolving metallic aluminum in the resulting mixture under conditions effective to form an alumina hydrosol containing ammonium chloride, said alumina hydrosol having an aluminum concentration in the range of from 7 wt.% to 14 wt.% and a weight ratio of aluminum to chloride in the range of from 0.6 to 1.3, wherein said weight ratio of aluminum to chloride is calculated on the basis of excluding the chlorine content of said ammonium chloride; (c) then commingling said alumina hydrosol with a gelling agent which hydrolyzes at an elevated temperature, thereby forming a mixture, and then dispersing said mixture as droplets in a suspending medium under conditions effective to transform said droplets into hydrogel particles; and (d) ageing said hydrogel particles first in said suspending medium and then in aqueous ammonia, and thereafter washing said hydrogel particles with water, then drying and calcining said hydrogel particles to obtain said spherical alumina particles. ### Claim 6 (depends on 5) A method according to claim 5 in which digestion of gibbsite in step (a) is carried out at a temperature in the range of from 160.degree. C. to 200.degree. C. and at a pressure in the range of from 4 Kg/cm.sup.2 to 10 Kg/cm.sup.2. ### Claim 7 (depends on 5) A method according to claim 5 in which step (b) is carried out at a temperature in the range of from 80.degree. C. to 105.degree. C. ### Claim 8 (depends on 5) A method according to claim 5 in which said gelling agent used in step (c) comprises hexamethylenetetramine and urea. ### Claim 9 (depends on 1, 5) A method according to claim 1 or claim 5 in which said suspending medium is an inert, organic oil immiscible with water having a temperature of from 50.degree. to 105.degree. C. ### Claim 10 (depends on 9) A method according to claim 9, in which said suspending medium is paraffin oil.