# US 2018/0022613 A1 · Method of producing a highly-pure aluminum hydroxide > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0022613 A1 - Document ID: US20180022613A1 - Status: Published application - Kind: A1 - Application number: 15/656,079 - Filed: 2017-07-21 - Published: 2018-01-25 - Earliest claimed: 2016-07-21 - Assignees: China Petroleum & Chemical Corporation; Research Institute of Petroleum Processing, Sinopec - Applicants: China Petroleum & Chemical Corporation; Research Institute of Petroleum Processing, Sinopec - Inventors: Yanpeng YANG; Aizeng MA - Web page: https://patentgrep.com/patent/US20180022613A1 ## CPC - C01F 7/42: Preparation of aluminium oxide or hydroxide from metallic aluminium, e.g. by oxidation - C01F 7/36: from organic aluminium salts - C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer - 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 producing a highly-pure aluminum hydroxide, comprising the following steps: (1) reacting alcohol with metal aluminum to produce aluminum alkoxide, then hydrolyzing the aluminum alkoxide with water to produce an aluminum hydroxide slurry and an alcohol, filtering the aluminum hydroxide slurry, washing a resulting filter cake with water to remove the alcohol trapped therein, and drying the filter cake after the water washing to produce an aluminum hydroxide powder, (2) sending the alcohol-containing water produced in step (1) to an alcohol extraction unit for separating water and alcohol through extraction, and sending the separated water back to step (1) for recycling, (3) dehydrating the hydrous alcohol produced by hydrolyzing the aluminum alkoxide in step (1) before using it as the raw materials for reacting metal aluminum with alcohol to produce aluminum alkoxide in step (1). The method can improve the recovery of alcohol, reduce the production cost of a highly-pure aluminum hydroxide, improve the purity of aluminum oxide and achieve a zero discharge of sewage by recycling water. ## Claims ### Claim 1 A method of producing a highly-pure aluminum hydroxide, comprising: (1) reacting alcohol with metal aluminum to produce aluminum alkoxide, then hydrolyzing the aluminum alkoxide with water to produce an aluminum hydroxide slurry and alcohol, filtering the aluminum hydroxide slurry, washing a resulting filter cake with water to remove the alcohol trapped therein, and drying the filter cake after washing with water to produce an aluminum hydroxide powder, (2) sending the alcohol-containing water produced in step (1) to an alcohol extraction unit for separating water and alcohol through extraction, and sending the separated water back to step (1) for recycling, (3) dehydrating the hydrous alcohol produced by hydrolyzing the aluminum alkoxide in step (1) before using it as the raw materials for reacting metal aluminum with alcohol to produce aluminum alkoxide in step (1). ### Claim 2 (depends on 1) The method according to claim 1, characterized in that gas is used for drying during the process of drying the filter cake in step (1) and the resulting dry off-gas is further washed with water to remove the alcohol therein. ### Claim 3 (depends on 2) The method according to claim 2, characterized in that the water used for washing the off-gas produced during the process of drying the filter cake is the water produced by the extraction separation in step (2). ### Claim 4 (depends on 3) The method according to claim 3, characterized in that the water obtained after water washing the off-gas from the process of drying the filter cake is used for washing the filter cake and hydrolyzing the aluminum alkoxide. ### Claim 5 (depends on 1) The method according to claim 1, characterized in that the alcohol in step (1) is C1-C20 alkanol. ### Claim 6 (depends on 1) The method according to claim 1, characterized in that temperature for reacting alcohol with metal aluminum in step (1) is from 60 to 200° C., and molar ratio of alcohol to metal aluminum is from 2 to 5:1. ### Claim 7 (depends on 1) The method according to claim 1, characterized in that temperature for hydrolyzing the aluminum alkoxide with water in step (1) is from 30 to 90° C., and weight ratio of water to aluminum alkoxide is from 0.5 to 5:1. ### Claim 8 (depends on 1) The method according to claim 1, characterized in that the solid content of the aluminum hydroxide slurry produced by hydrolyzing the aluminum alkoxide in step (1) is from 7 to 12 wt. %, calculated as aluminum oxide. ### Claim 9 (depends on 1) The method according to claim 1, characterized in that the alcohol content of the aluminum hydroxide slurry produced by hydrolyzing the aluminum alkoxide in step (1) is from 1 to 30 wt. %. ### Claim 10 (depends on 1) The method according to claim 1, characterized in that a diameter of the aluminum hydroxide particles is from 0.5 μm to 1000 μm in the aluminum hydroxide slurry obtained by hydrolyzing the aluminum alkoxide in step (1). ### Claim 11 (depends on 1) The method according to claim 1, characterized in that temperature for washing the filter cake with water in step (1) is from 40 to 90° C. ### Claim 12 (depends on 1) The method according to claim 1, characterized in that times for washing the filter cake with water in step (1) is from 1 to 3 times. ### Claim 13 (depends on 1) The method according to claim 1, characterized in that an amount of washing water in the process of washing the filter cake with water in step (1) is from 1 to 10 times the weight of the filter cake. ### Claim 14 (depends on 1) The method according to claim 1, characterized in that an extraction agent used for separating water and alcohol through extraction in step (2) is C6-C9 arene or C6-C9 alkane. ### Claim 15 (depends on 1) The method according to claim 1, characterized in that the alcohol-containing water produced in step (1) is the filtrate obtained after filtrating the aluminum hydroxide slurry and/or the wash solution after water washing the filter cake. ### Claim 16 (depends on 1) The method according to claim 1, characterized in that the temperature for the extraction separation of water and alcohol in step (2) is from 50 to 90° C. ### Claim 17 (depends on 1) The method according to claim 1, characterized in that after the extraction separation in step (2), a resulting extraction phase is rectified to separate the extraction agent and the alcohol, the extraction agent is recycled, and the alcohol is used in the raw materials for reacting metal aluminum with alcohol to produce aluminum alkoxide in step (1). ### Claim 18 (depends on 14) The method according to claim 14, characterized in that the temperature for the extraction separation of water and alcohol in step (2) is from 50 to 90° C. ### Claim 19 (depends on 14) The method according to claim 14, characterized in that after the extraction separation in step (2), a resulting extraction phase is rectified to separate the extraction agent and the alcohol, the extraction agent is recycled, and the alcohol is used in the raw materials for reacting metal aluminum with alcohol to produce aluminum alkoxide in step (1).