Production of phosphoric acid
US4557915A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 5, 1984 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Jul 5, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/2208
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Phosphoric acid is produced, with concomitant recovery of solids comprising compounds of fluorine and silica, by (i) acidulating a first amount of phosphate ore with a strong acid to produce a first phosphoric acid slurry, (ii) filtering said first slurry to separate the liquid phosphoric acid content therefrom, (iii) concentrating a fraction of the phosphoric acid thus separated, (iv) recovering same, and (v) condensing the evolved vapors of concentration with a liquid absorbent to produce a solution of fluosilicic acid, (vi) acidulating a second amount of phosphate ore with said solution of fluosilicic acid together with a fraction of said first slurry, or together with a fraction of the phosphoric acid separated in the step (ii), to produce a second phosphoric acid slurry, (vii) filtering said second slurry to separate both the liquid phosphoric acid content and a solids fraction therefrom, said solids fraction comprising fluorine and silica compounds, (viiia) recycling the phosphoric acid thus separated from said second slurry to the step (i), or (viiib) combining same with the fraction of separated phosphoric acid to be downstream concentrated in the step (iii).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.