Method for producing phosphoric acid and by-producing alpha-hemihydrate gypsum by wet-process
US10745278B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Aug 26, 2016 |
| Grant date | Aug 18, 2020 |
| Priority date | — |
| Expiry date | Oct 13, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F11/466
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Provided is a method for producing phosphoric acid and at the same time obtaining alpha-hemihydrate gypsum including: adding a phosphate rock powder and a part of dilute sulfuric acid into an extraction tank, carrying out an extraction reaction on same, separating a clear liquid from the obtained mixed slurry, sending the clear liquid, as a finished product phosphoric acid, into an acid storeroom, and transferring a separated solid, together with the rest mixed slurry, into a crystal transformation tank; and adding sulfuric acid and a crystal transformation agent into the crystal transformation tank, carrying out a crystal transformation reaction for 1.5-7.5 h at 60° C.-130° C., and solid-liquid separating the obtained mixed acid slurry, wherein the solid can be dried into a gypsum powder, or may be not subjected to a drying step and made into gypsum products such as gypsum boards, gypsum building blocks and gypsum members by directly adding water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.