Mineral fillers

摘要

In a method of dewatering by pressure filtration an aqueous suspension of a clay containing a small proportion of particles having an equivalent spherical diameter smaller than 1 micron, the improvement which comprises treating the aqueous suspension of the clay, prior to dewatering by pressure filtration at a pressure in excess of 150 pounds per square inch, with a water-soluble polyelectrolyte flocculant having a high density of positive charges.