to clean and make natural forekommande kalciumkarbonatmineral brighter

摘要

A method for brightening a natural calcitic ore by removal of discoloring contaminants. The ore is crushed and formed into an aqueous slurry, which slurry is then coarse-milled to produce a product wherein no more than 1 percent of the particulate matter is +325 mesh. This coarse-milled product is then subjected to a further, wet-milling step, to alter the particulate such that at least 70 percent of the particles are less than 2 microns, thereby liberating substantial quantities of the discoloring contaminants. The liberated impurities are thereupon separated from the slurry by flotation and/or by subjecting the slurry to a high intensity magnetic field.