| 摘要 |
PURPOSE:To improve filtering characteristics and to make it possible to reduce liquid content in hemihydrate prepared by filtration in filtering highly concentrated phosphoric acid-hemihydrate slurry by a vacuum filter, by adding a specific flocculant to slurry and filtering. CONSTITUTION:In filtering highly concentrated phosphoric acid-hemihydrate slurry obtained by wet type phosporic acid production by the use of a vacuum filter, the following flocculant is added to the slurry and the slurry is filtered Namely, an anionic polyacrylamide type high polymer flocculant, a high copolymer of acrylamide and sodium acrylate having 3-6mol% sodium acrylate content is used as the flocculant. The amount of the flocculant added is preferably 0.5-5ppm based on the highly concentrated phosphoric acid-hemihydrate slurry.
|
