Method for brightening natural calcitic ores
US4165840A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1978 |
| Grant date | Aug 28, 1979 |
| Priority date | — |
| Expiry date | Jan 10, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/60
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method is disclosed for processing a natural calcitic ore to yield a finely divided calcium carbonate particulate of very high brightness characteristics. The natural calcitic ore is initially coarse-milled to produce a product wherein no more than 5% by weight of the particulate is +325 mesh, and no more than 35% by weight of the particles are of less than 2 microns E.S.D. This coarse-milled product is then subjected as an aqueous slurry including less than 40% solids, to a froth flotation, which separates with the froth the relatively coarse colorbodies liberated in the initial grinding. The purified underflow is then dewatered to at least 60% solids by weight, and is wet-milled, as for example in a sand mill, to yield an output product wherein at least 80% by weight of the resultant particulate has an E.S.D. of less than 2 microns, the product being further characterized by a brightness of at least 94 on the G.E. scale.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.