Method for the production of precipitated calcium carbonate having a selected crystal form, products produced thereby and their uses
US6221146A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1999 |
| Grant date | Apr 24, 2001 |
| Priority date | — |
| Expiry date | Apr 1, 2019 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H17/675
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of producing a precipitated calcium carbonate (pcc) product which has a coarse crystalline form which comprises the steps of: PA1 (a) preparing a suspension in an aqueous medium of calcium hydroxide particles which partially dissolve as calcium ions in the aqueous medium, the aqueous medium also incorporating an agent which promotes release into solution in the aqueous medium of calcium ions from the calcium hydroxide; PA1 (b) adding carbon dioxide to the aqueous medium to react with the calcium ions therein to produce a suspension in the aqueous medium of a precipitate of calcium carbonate crystals; PA1 (c) concentrating the suspension of the precipitate by a dewatering process; and PA1 (d) adding to the suspension of the precipitate a dispersing agent for the precipitate; wherein in step (a) the calcium hydroxide particles of the suspension of calcium hydroxide particles have a specific surface area measured by the BET nitrogen method of less than 33 m.sup.2 /g and the said agent comprises a water soluble organic compound present in an amount of from about 0.010% to about 0.20% by weight based on the dry weight of calcium carbonate to be produced from the calcium hydroxi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.