METHODS AND SYSTEMS FOR CLASSIFICATION AND RECOVERY

1 . A method of classification and recovery, the method comprising:

providing a first stream comprising a first plurality of solids, wherein the first plurality of solids comprises a material of interest, and wherein a first portion of the first plurality of solids has sizes greater than a first cut-off particle size, and a second portion of the first plurality of solids has sizes less than or equal to a first cut-off particle size;

disposing the first stream in a first solid bowl centrifuge to produce (i) a first cake comprising a second plurality of solids, the second plurality of solids comprising at least 50%, by weight, of the first portion of the first plurality of solids, and (ii) a first centrate comprising a third plurality of solids, the third plurality of solids comprising at least 50%, by weight, of the second portion of the first plurality of solids; and

(A) subjecting the first cake or the first centrate to a valorization procedure to produce a product stream comprising at least a portion of the material of interest; or

(B) disposing the first cake in a second solid bowl centrifuge to produce (a) a second cake comprising a fourth plurality of solids, and (b) a second centrate comprising a fifth plurality of solids, and

subjecting the second cake or the second centrate to a valorization procedure to produce a product stream comprising at least a portion of the material of interest;

wherein a first portion of the second plurality of solids of the first cake has sizes greater than a second cut-off particle size, and a second portion of second plurality of solids of the first cake has sizes less than or equal to a second cut-off particle size,

wherein the fourth plurality of solids of the second cake comprises at least 50%, by weight, of the first portion of the second plurality of solids, and

wherein the fifth plurality of solids of the second centrate comprises at least 50%, by weight, of the second portion of the second plurality of solids; or

(C) disposing the first centrate in a second solid bowl centrifuge to produce (a) a second cake comprising a fourth plurality of solids, and (b) a second centrate comprising a fifth plurality of solids, and

subjecting the second cake or the second centrate to a valorization procedure to produce a product stream comprising at least a portion of the material of interest;

wherein a first portion of the third plurality of solids of the first centrate has sizes greater than a second cut-off particle size, and a second portion of third plurality of solids of the first centrate has sizes less than or equal to a second cut-off particle size,

wherein the fourth plurality of solids of the second cake comprises at least 50%, by weight, of the first portion of the third plurality of solids, and

wherein the fifth plurality of solids comprises at least 50%, by weight, of the second portion of the third plurality of solids.

2 . The method of claim 1 , wherein the first cut-off particle size and, if applied, the second cut-off particle size, independently, are selected from about 2 μm to about 100 μm, and wherein the valorization procedure—

(i) recovers in the product stream at least 10%, by weight, more of the material of interest than an identical valorization procedure performed directly on the first stream,

(ii) has a throughput capacity that is at least 20% greater than an identical valorization procedure performed directly on the first stream,

(iii) achieves an uplift in grade of the material of interest of at least 4 percentage points relative to an identical valorization procedure performed directly on the first stream, or

(iv) a combination thereof.

3 . The method of claim 2 , wherein the first cut-off particle size and, if applied, the second cut-off particle size, independently, are selected from about 2 μm to about 40 μm.

4 . The method of claim 1 , wherein the first cake is subjected to the valorization procedure.

5 . The method of claim 1 , wherein the first cut-off particle size is greater than the second cut-off particle size.

6 . The method of claim 5 , wherein the first centrate is disposed in the second solid bowl centrifuge to produce the second cake and the second centrate.

7 . The method of claim 6 , wherein the second cake is subjected to the valorization procedure.

8 . The method of claim 1 , wherein the first cut-off particle size is less than the second cut-off particle size.

9 . The method of claim 8 , wherein the first cake is disposed in the second solid bowl centrifuge to produce the second cake and the second centrate.

10 . The method of claim 9 , wherein the second cake is disposed in the second solid bowl centrifuge.

11 . The method of claim 1 , wherein the first cut-off particle size and, if applied, the second cut-off particle size are independently selected from about 2 μm to about 100 μm.

12 . The method of claim 1 , wherein the first cut-off particle size and, if applied, the second cut-off particle size are independently selected from about 2 μm to about 40 μm.

13 . The method of claim 1 , wherein the first cut-off particle size is about 15 μm to about 40 μm, and the first centrate is disposed in the second solid bowl centrifuge, and wherein the second cut-off particle size is about 2 μm to about 12 μm, and the second cake is subjected to the valorization procedure.

14 . The method of claim 1 , wherein the valorization procedure comprises a flotation procedure, a leaching procedure, a magnetic separation procedure, or a combination thereof.

15 . The method of claim 14 , wherein the flotation procedure comprises reverse flotation and direct flotation.

16 . The method of claim 15 , wherein the flotation procedure comprises:

contacting a liquid and (i) the first cake or (ii) the second cake to produce a diluted cake;

subjecting the diluted cake to reverse flotation to produce a first froth and a second stream comprising an underflow of the reverse flotation, wherein the second stream comprises a first amount of the material of interest; and

subjecting the second stream to direct flotation to produce a second froth and a third stream comprising an underflow of the direct flotation;

wherein the second froth is the product stream, which comprises a second amount of the material of interest.

17 . The method of claim 1 , wherein the first stream comprises a tailings stream, a cyclone overflow, or a flotation feed stream.

18 . The method of claim 1 , further comprising contacting the first stream and one or more additives before, during, and/or after the disposing of the first stream in the first solid bowl centrifuge.

19 . The method of claim 1 , wherein the material of interest comprises one or more phosphorus-containing compounds, one or more metals, one or more metal-containing compounds, one or more minerals, or a combination thereof.

20 . A system for classification and recovery of a material of interest, the system comprising:

a first solid bowl centrifuge;

optionally a second solid bowl centrifuge; and

a valorization apparatus, wherein the valorization apparatus is configured to receive a first cake, a second cake, a diluted first cake, or a diluted second cake from the first or the second solid bowl centrifuge.