Seeding of aragonite calcium carbonate and the product thereof
US6156286A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1997 |
| Grant date | Dec 5, 2000 |
| Priority date | — |
| Expiry date | May 21, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/26
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Fine-grained aragonite precipitated calcium carbonate is produced on a commercial scale by seeding with a coarse-grained aragonite precipitated calcium carbonate. The coarse-grained seeding material is produced by interrupting, after the production of 0.1 to 0.6 g/L min. of calcium carbonate, the supply of carbon dioxide to the quicklime slurry early in the reaction to allow subsequent nucleation of the crystals and then continuing the supply of carbon dioxide at reaction rates of 0.1 g/L min. to 0.6 g/L min. This coarse-grained seeding material has a Blaine surface area which may be less than 30,000 cm.sup.2 /g, the solids of which are 35 to 70 weight percent aragonite, and is added to subsequent batches as a slurry at about 1 weight percent, based on the total weight of the slurry of the material to be seeded. For the seeded batches, carbonation is carried out at reaction rates of up to 1.8 g/L min. at the commercial scale resulting in fine-grained aragonite product. This final seeded product need not be ground, has solids in which the weight percent of aragonite is greater than 90, has a median particle size between 0.30 to about 0.5 microns, a particle size distribution where a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.