Patent · US Expired

Process for the dearsenication of polyphosphoric acid

US3991164A · kind A · utility

4Cited by

4References

5Claims

0Family size

Assignee

Hoechst GmbH · DE

Inventors

Wolfgang Scheibitz · Frankfurt am Main, DE
Hasso Spott
Gero Heymer · Lechenich, DE

Key dates

Filing date	Oct 15, 1974
Grant date	Nov 9, 1976
Priority date	—
Expiry date	Oct 15, 1994

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC01B25/24
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

Polyphosphoric acid is dearsenicated by placing the polyphosphoric acid in a reactor; adding a phosphorus oxo-compound containing phosphorus in the monovalent or trivalent electropositive oxidation stage; heating the resulting mixture to effect disproportionation of the phosphorus oxo-compound; and removing the resulting off-gas having arsenic therein.

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