Patent ID: 7285225
Filing Date: 2007-10-23
Classification: B01D,C01P,C09C,C09D

Abstract:
1. A method for dewatering a slurry of titanium dioxide having an initial specific gravity of from about 1.01 to about 1.8 using a filtration system comprising a filter stack, a means for oscillating said filter stack, a feed tank, a permeate holding tank, a concentrate removal line and a water source, said filter stack comprising filter disks and diverter trays, wherein the method comprises the steps of: initially removing a sufficient quantity of said slurry having a specific gravity of from about 1.2 to about 1.8 from said feed tank such that addition of water or permeate to the remaining slurry in said feed tank will yield a slurry having a specific gravity ranging from about 1.01 to about 1.1; passing permeate fluid from said permeate holding tank through said filter stack for period of time ranging from about 20 minutes to about 16 hours; initiating fluid flow from said feed tank while directing concentrate flow from said filter stack to said feed tank; increasing the specific gravity of the slurry in said feed tank at a rate of about 0.1 per hour to a range of about 1.4 to about 1.8, wherein following the increase in specific gravity of said slurry entering said filter stack, said concentrate removed from said filter stack has a specific gravity ranging from about 2.0 to about 2.3 and said permeate removed from said filter stack has a specific gravity ranging from about 1.0 to about 1.1; adjusting fluid pressure of fluid entering said filter stack to a pressure between about 275 kPa and about 830 kPa; initiating oscillation of said filter stack; and, subsequently setting the oscillation amplitude of said filter stack to a distance between about 0.6 cm and about 3.8 cm.