Process for producing hydrogen fluoride from an aqueous hydrofluorosilicic acid solution

US4067957A · kind A · utility

Assignee

• Fitzwilton Limited · IE

Inventors

• Ralph E. Worthington · Dublin, IE
• Padraic S. O'Neill · Dublin, IE

Key dates

• Filing date: Jul 8, 1976
• Grant date: Jan 10, 1978
• Expiry date: Jul 8, 1996

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B7/193
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Potassium fluoride and silica are reacted with an aqueous solution of hydrofluorosilicic acid. The resulting potassium fluorosilicate is recovered. The potassium fluorosilicate may be further reacted with ammonia in water to form an aqueous mixture of ammonium fluoride and potassium fluoride. The ammonium fluoride is then heated in aqueous solution in the presence of excess potassium fluoride to release ammonia and to form potassium bifluoride. The potassium bifluoride is recovered from solution substantially free from ammonia and heated to release hydrogen fluoride. Alternatively, the recovered potassium bifluoride may be reacted with sodium fluoride to produce sodium bifluoride. The sodium bifluoride is then heated to release hydrogen fluoride.