Granted Patent B2

US 8,696,404 · App. 13/333,950 · Granted Apr 15, 2014

Abstract

Claims (31)

1. A system for recycling a preselected slurry material from a polishing assembly, the system comprising:

the polishing assembly comprising:

a polisher having an inlet and a drain outlet; and

a slurry storage tank configured to supply a slurry comprising a preselected material to the inlet of the polisher; and

a recycling assembly comprising:

a cross flow filter comprising an inlet configured to receive a waste slurry comprising the preselected material from the drain outlet of the polisher, wherein the cross flow filter is configured to concentrate the preselected material in a slurry provided at an outlet of the cross flow filter;

a density meter configured to measure a concentration of the preselected material in the outlet slurry of the cross flow filter;

a valve coupled to the outlet of the cross flow filter and configured to supply the slurry storage tank; and

a controller coupled to the density meter and the valve, wherein the controller is configured to open the valve when the concentration of the preselected material reaches a first preselected concentration threshold, wherein the density meter is configured to measure a resonant frequency of the outlet slurry from the cross flow filter.

2. The system of claim 1 , wherein the density meter is configured to measure the resonant frequency of the outlet slurry from the cross flow filter in a U-shaped tube.

3. The system of claim 1 , further comprising:

a first pump configured to receive the outlet slurry of the cross flow filter;

a concentrate storage tank coupled to the first pump and configured to store the outlet slurry of the cross flow filter;

a second pump coupled to the concentrate storage tank;

a second valve coupled between the pump and the slurry storage tank;

a second density meter configured to measure a concentration of the preselected material in the slurry storage tank;

wherein the controller is configured to open the second valve when the concentration of the preselected material measured by the second density meter is below a second preselected concentration threshold.

4. The system of claim 3 , wherein the second preselected concentration threshold is about 5 percent, and wherein the first preselected concentration threshold is about 10 percent.

5. The system of claim 1 , wherein the first preselected concentration threshold is about 10 percent.

6. The system of claim 1 , wherein the preselected material comprises a preselected rare earth oxide.

7. The system of claim 6 , wherein the preselected rare earth oxide comprises ceria.

8. The system of claim 1 , further comprising a separator valve positioned between the polisher and the cross flow filter, wherein the separator valve is configured to eliminate a portion of the waste slurry having a concentration of the preselected material below a third preselected threshold.

9. The system of claim 1 , wherein the polishing assembly further comprises a pump coupled to the polisher and configured to direct a portion of the slurry from the polisher to the slurry storage tank.

10. The system of claim 1 , wherein the cross flow filter comprises a plurality of membranes.

11. The system of claim 10 , wherein the plurality of membranes each comprise an elongated tubular shape.

12. The system of claim 11 , wherein the plurality of membranes each comprise an opening along a side wall of the elongated tubular shape.

13. The system of claim 12 :

wherein a first slurry is configured to exit ends of the elongated tubular shaped membranes;

wherein a second slurry is configured to exit the side walls of the elongated tubular shaped membranes;

wherein a concentration of the preselected material in the first slurry is greater than a concentration of the preselected material in the second slurry.

14. The system of claim 12 , wherein a size of a particle of the preselected material is greater than a size of the opening.

Assignments (10)