Production of hydrogen fluoride
AssigneeGoulding Chemicals Limited
InventorsRalph E. Worthington, Padraic S. O'Neill, Paul F. X. Hackett
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Abstract
Hydrogen Fluoride is manufactured from fluorosilicic acid. The fluorosilicic acid is reacted with ammonia to produce aqueous ammonium fluoride and solid silica. The ammonium fluoride is hydrolised in the presence of a mixture of ammonium fluoride and ammonium bifluoride, and the net production of ammonium bifluoride is converted to sodium bifluoride. The sodium bifluoride is decomposed by heating to hydrogen fluoride gas.
Claims7
A process for preparing sodium bifluoride, which comprises feeding aqueous ammonium fluoride to a continuously operated reactor containing a mixture of ammonium fluoride and ammonium bifluoride in aqueous solution, the mixture containing 7.0 to 11.0 moles per liter of fluoride ions and 2.5 to 6.0 moles per liter of bifluoride ions, and boiling at a temperature of from 130.degree. to 150.degree. C. under a pressure of from 10 to 30 psig, whereby there is a net production of ammonium bifluoride from ammonium fluoride with the release of ammonia;
- withdrawing aqueous reaction liquor containing ammonium fluoride and ammonium bifluoride from said reactor;
- cooling the withdrawn reaction liquor to a temperature of from 10.degree. to 50.degree. C.;
- contacting the cooled reaction liquor with sodium fluoride whereby the sodium fluoride reacts with the ammonium bifluoride to produce sodium bifluoride;
- and recovering said sodium bifluoride.
A process for the manufacture of hydrogen fluoride from fluorosilicic acid, which comprises reacting the fluorosilicic acid with ammonia to produce aqueous ammonium fluoride and solid silica;
- feeding the aqueous ammonium fluoride to a continuously operated reactor containing a mixture of ammonium fluoride and ammonium bifluoride in aqueous solution, the mixture containing 7.0 to 11.0 moles per liter of fluoride ions and 2.5 to 6.0 moles per liter of bifluoride ions, and boiling at a temperature of from 130.degree. to 150.degree. C. under a pressure of from 10 to 30 psig, whereby there is a net production of ammonium bifluoride from ammonium fluoride with the release of ammonia;
- withdrawing aqueous reaction liquor containing ammonium fluoride and ammonium bifluoride from said reactor;
- cooling the withdrawn reaction liquor to a temperature of from 10.degree. to 50.degree. C.;
- contacting the cooled reaction liquor with sodium fluoride whereby the said fluoride reacts with the ammonium bifluoride to produce sodium bifluoride;
- recovering said sodium bifluoride;
- and decomposing said sodium bifluoride by heating to form hydrogen fluoride gas and solid sodium fluoride.
Dependencies are inferred from the claim text.