Precipitated calcium carbonate from pulp mill waste having an improved brightness, method for the production and use thereof
US9409788B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 2012 |
| Grant date | Aug 9, 2016 |
| Priority date | — |
| Expiry date | May 20, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08K2003/265
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention relates to a process for the production of a precipitated divalent metal ion carbonate product from a divalent metalion carbonate which was recovered from waste, the precipitated divalent metal ion carbonate product having an improved brightness, the process comprising the steps of: providing a low-purity divalent metal ion carbonate material, the divalent metal ion carbonate material being recovered from waste; calcining the divalent metal ion carbonate material in order to obtain a divalent metal ion oxide; slaking the divalent metal ion oxide in order to obtain an aqueous suspension of a divalent metal ion hydroxide; carbonating the aqueous suspension of the divalent metal ion hydroxide with a carbon dioxide containing compound in order to obtain fine precipitated divalent metal ion carbonate particles; post-treating the fine precipitated divalent metal ion carbonate particles to obtain fine discrete precipitated divalent metal ion carbonate particles; adding the fine discrete precipitated divalent metal ion carbonate particles to an aqueous suspension of divalent metal ion hydroxide that was obtained by slaking high-purity divalent metal ion hydroxide in o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.