ZPUSOB VYROBY KALCINOVANEHO JILU S NIZKYM OTEREM A VYSOKOU OPTICKOU ODRAZNOSTI

摘要

A method is disclosed for separating titaniferous and ferruginous discolorants from a crude kaolin clay. A dispersed aqueous slurry of the clay is formed containing a deflocculant and a fatty acid collecting agent, and the slurry is conditioned to coat the discolorants with the collecting agent to thereby render the discolorants hydrophobic. A system of sub-micron sized magnetic ferrite seeding particles, the surfaces of which have been rendered hydrophobic, is thereupon added to the slurry. The seeded slurry is mixed to coalesce the hydrophobic-surfaced discolorants with the hydrophobic-surfaced seeding particles, and the slurry is then subjected to a froth flotation, which removes substantial quantities of the discolorants and seeding partices coalesced therewith, and also removes excess seeding particles and excess collecting agent. The floatation-beneficiated slurry is then subjected to a magnetic separation by passing the slurry through a porous ferromagnetic matrix positioned in a magnetic field, having an intensity of at least 0.5 kilogauss, to remove further quantities of the discolorants and seeding particles associated therewith, and to remove seeding particles unassociated with said discolorants. The product from said magnetic separation may then be calcined at a temperature of at least 1500 DEG F. to yield an exceptionally high brightness, low abrasion product.