Patent · US Expired

Isolating fluorine compounds from the vapors obtained when evaporatively concentrating phosphoric acid

US4269609A · kind A · utility

2Cited by

4References

4Claims

0Family size

Assignee

BASF SE

Inventors

Andreas Brunold · Frankenthal (Pfalz), DE
Peter Kroetzsch · Ketsch, DE
Lothar Diehl · Stuttgart, DE

Key dates

Filing date	Jan 31, 1980
Grant date	May 26, 1981
Priority date	—
Expiry date	Jan 31, 2000

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB01D53/68
WIPO fieldChemical engineering
WIPO sectorChemistry

Abstract

Fluorine compounds which are contained in the vapors obtained when evaporatively concentrating phosphoric acid are removed by scrubbing with an aqueous solution of fluosilicic acid under reduced pressure at a temperature at which condensation of steam is substantially avoided. The aqueous fluosilicic acid solutions are injected, at a speed of from 15 m/s to 40 m/s, into the upper part of a scrubbing zone, finely dispersed over the entire cross-section of the latter. The vapors are passed through the scrubbing zone at a speed of from 5 to 30 m/s, in co-current with the fluosilicic acid solutions. The residence time of the vapors in the scrubbing zone is from 0.4 to 1.5 s. The fluosilicic acid taken off the scrubbing zone contains from 20 to 28% by weight of H.sub.2 SiF.sub.6.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.