# US 4,399,113 A · Process for treating a gas containing a fluorine compound > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,113 A - Document ID: US4399113A - Status: Granted - Kind: A - Application number: 06/321,712 - Filed: 1981-11-16 - Granted: 1983-08-16 - Earliest claimed: 1980-12-11 - Assignees: Mitsubishi Light Metal Industries Limited - Inventors: Susumu Tosaka; Tadamichi Abe; Hozumi Endo; Kiyohiro Ogawa - Web page: https://patentgrep.com/patent/US4399113A ## CPC - C01F 7/50: Fluorides - B01D 53/68: Halogens or halogen compounds - 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}) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract A process for treating a gas containing a fluorine compound which comprises the steps of contacting said gas with an aqueous solution as an absorbent containing aluminum fluoride and sulfate radical at a concentration of 3 to 30 g/l to absorb the fluorine compound, producing a solid phase including aluminum fluoride hydrate and/or basic aluminum fluoride by adding aluminum hydroxide and/or alumina to the resultant aqueous solution obtained in the absorbing step, and separating said solid phase from a slurry containing said solid phase obtained in the producing step. ## Claims ### Claim 1 A process for treating a gas containing a fluorine compound which comprises the steps of: contacting said gas with an aqueous solution as an absorbent containing aluminum fluoride and sulfate radical at a concentration of 3 to 30 g/l to absorb the fluorine compound, producing a solid phase including aluminum fluoride hydrate and/or basic aluminum fluoride by adding aluminum hydroxide and/or alumina to the resultant aqueous solution obtained in the absorbing step, and separating said solid phase from a slurry containing said solid phase obtained in the producing step. ### Claim 2 (depends on 1) The process according to claim 1, wherein the concentration of the sulfate radical contained in the aqueous solution as an absorbent is maintained at a predetermined value by adding a substance containing sulfate radical in the absorbent in the absorbing step. ### Claim 3 (depends on 2) The process according to claim 2, wherein the substance containing sulfate radical is sulfuric acid or aluminum sulfate. ### Claim 4 (depends on 2) The process according to claim 2, wherein the substance containing sulfate radical is amorphous aluminum hydroxide containing sulfate radical. ### Claim 5 (depends on 1) The process according to claim 1, wherein the absorbing step comprises a former absorbing step wherein the gas containing a fluorine compound is treated with an aqueous solution as a former absorbent containing aluminum fluoride and sulfate radical at a concentration of 3 to 30 g/l, and a latter absorbing step wherein the once treated gas containing the fluorine compound discharged from the former absorbing step is further treated with an aqueous solution as a latter absorbent of pH 1 to 4 containing amorphous aluminum hydroxide. ### Claim 6 (depends on 5) The process according to claim 5, wherein amorphous aluminum hydroxide to be added to the latter absorbent contains sulfate radical. ### Claim 7 (depends on 5, 6) The process according to claim 5 or 6, wherein a part of the latter absorbent is withdrawn and the withdrawn part thereof is combined with the former absorbent.