AUTOCLAVE WITH UNDERFLOW DIVIDERS

• US 20070217285A1
• Filed: 03/14/2007
• Published: 09/20/2007
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Barrick Gold Corporation
• Original Assignee: Barrick Gold Corporation
• Inventors: Ji, Jinxing, King, James
• Granted Patent: US 8,061,888 B2
• Time in Patent Office: Days
• US Class Current: 366/291
• CPC Class Codes: B01F 27/2322 with parallel axes
• CPC Class Codes: B01F 27/90 with paddles or arms
• CPC Class Codes: B01F 33/81 Combinations of similar mixers, e.g. with rotary stirring devices in two or more receptacles
• CPC Class Codes: B01F 33/813 mixing simultaneously in two or more mixing receptacles
• CPC Class Codes: B01F 35/52 Receptacles with two or more compartments
• CPC Class Codes: B01J 19/006 Baffles
• CPC Class Codes: B01J 2219/00768 vertical
• CPC Class Codes: B01J 2219/182 horizontal
• CPC Class Codes: B01J 3/042 in the form of a tube

Abstract

The present invention is directed to a multi-compartment autoclave using inter-compartment dividers having one or more underflow openings for passing a feed stream between compartments.

Claims

1. A stirred tank reactor, comprising:

(a) a plurality of compartments;

(b) a plurality of agitators positioned in the plurality of compartments; and

(c) a plurality of dividers separating the plurality of compartments, each of the dividers including at least one underflow opening, wherein a feed stream flows between adjacent compartments by passing through the at least one underflow opening in the divider separating the adjacent compartments.

2. The autoclave of claim 1, wherein each of the dividers is higher than a feed stream level in an adjacent, upstream compartment and wherein the height-to-diameter ratio of each of the dividers is at least about 0.80.

3. The autoclave of claim 1, wherein, in each of the dividers, the cumulative cross-sectional area of the at least one underflow opening ranges from about 0.06 m² to about 1.50 m² and wherein the flow volume between adjacent compartments ranges from about 200 m³/hour to about 800 m³/hour.

4. The autoclave of claim 3, wherein the cumulative cross-sectional area of the at least one underflow opening in each of the dividers is different, with the cumulative cross-sectional area of at least one underflow opening in a first divider at an input end of the reactor is less than the cumulative cross-sectional area of the at least one underflow opening in a second divider, the second divider being nearer an output end of the reactor than the first divider.

5. The autoclave of claim 1, wherein, in each of the plurality of dividers, the at least one underflow opening is positioned at or below an uppermost impeller blade of the agitator in the adjacent, upstream compartment.

6. The autoclave of claim 1, wherein, in each of the plurality of dividers, the at least one underflow opening is positioned above the bottom of the autoclave at a height that is no more than about 33% of the liquid level in the adjacent, upstream compartment.

7. The autoclave of claim 1, wherein agitators in a plurality of sets of adjacent compartments counter-rotate.

8. The autoclave of claim 7, wherein, in a first compartment, a first agitator rotates clockwise and the at least one underflow opening in a first divider, separating the first compartment from an adjacent second compartment, is positioned to the right of a longitudinal axis of the autoclave and wherein, in the second compartment, a second agitator rotates counterclockwise and the at least one underflow opening in a second divider separating the second compartment from an adjacent third compartment, is positioned to the left of the longitudinal axis of the autoclave.

9. A method for processing a feed stream, comprising:

(a) introducing the feed stream into an autoclave, the autoclave comprising a plurality of compartments, a plurality of agitators positioned in the plurality of compartments, and a plurality of dividers separating the plurality of compartments, each of the dividers including at least one underflow opening;

(b) introducing a molecular oxygen-containing gas into the autoclave; and

(c) passing at least most of the feed stream between sets of adjacent compartments through the at least one underflow opening in the divider separating the adjacent compartments.

10. The method of claim 9, wherein each of the dividers are higher than a feed stream level in an adjacent, upstream compartment and wherein the underflow opening and wherein the height-to-diameter ratio of each of the dividers is at least about 0.80.

11. The method of claim 9, wherein, in each of the dividers, the cumulative cross-sectional area of the at least one underflow opening ranges from about 0.06 to about 1.50 m² and wherein the flow volume between adjacent compartments ranges from about 200 to about 800 m³/hour.

12. The method of claim 11, wherein the cumulative cross-sectional area of the at least one underflow opening in each of the dividers is different, with the cumulative cross-sectional area of at least one underflow opening in a first divider at an input end of the reactor is less than the cumulative cross-sectional area of the at least one underflow opening in a second divider, the second divider being nearer an output end of the reactor than the first divider.

13. The method of claim 9, wherein, in each of the plurality of dividers, the at least one underflow opening is positioned at or below an uppermost impeller blade of the agitator in the adjacent, upstream compartment.

14. The method of claim 9, wherein, in each of the plurality of dividers, the at least one underflow opening is positioned above the bottom of the autoclave at a height that is no more than about 33% of the liquid level in the adjacent, upstream compartment.

15. The method of claim 9, wherein agitators in a plurality of sets of adjacent compartments counter-rotate.

16. The method of claim 15, wherein, in a first compartment, a first agitator rotates clockwise and the at least one underflow opening in a first divider, separating the first compartment from an adjacent second compartment, is positioned to the right of a longitudinal center line of the autoclave and wherein, in the second compartment, a second agitator rotates counterclockwise and the at least one underflow opening in a second divider separating the second compartment from an adjacent third compartment, is positioned to the left of the longitudinal center line of the autoclave.

17. A method for processing a metal sulfide-containing material, comprising:

(a) introducing into an autoclave an input slurry comprising a comminuted metal sulfide-containing material, the autoclave comprising a plurality of compartments for receiving the input slurry, a plurality of agitators positioned in the plurality of compartments for mixing the input slurry, and a plurality of dividers separating the plurality of compartments, each of the dividers including at least one underflow opening for passing the input slurry from compartment to compartment;

(b) introducing a molecular oxygen-containing gas into the autoclave;

(c) oxidizing the metal sulfide-containing material in the input slurry to provide a product slurry comprising the oxidized metal-containing material, wherein the oxidizing step comprises the substep of passing at least most of the slurried material between sets of adjacent compartments through the at least one underflow opening in the divider separating the adjacent compartments; and

(d) thereafter recovering the metal from the product slurry.

18. The method of claim 17, wherein the metal is at least one of a base metal, a platinum group metal, and a precious metal, wherein each of the dividers are higher than a feed stream level in an adjacent, upstream compartment, and wherein the underflow opening and wherein the height-to-diameter ratio of each of the dividers is at least about 0.80.

19. The method of claim 17, wherein, in each of the dividers, the cumulative cross-sectional area of the at least one underflow opening ranges from about 0.06 to about 1.50 m², wherein the flow volume between adjacent compartments ranges from about 200 to about 800 m³/hour, and wherein the cumulative cross-sectional area of the at least one underflow opening in each of the dividers is substantially the same.

20. The method of claim 17, wherein, in each of the plurality of dividers, the at least one underflow opening is positioned above the bottom of the autoclave at a height that is no more than about 33% of the liquid level in the adjacent, upstream compartment.

21. The method of claim 17, wherein, in a first compartment, a first agitator rotates clockwise and the at least one underflow opening in a first divider, separating the first compartment from an adjacent second compartment, is positioned to the right of a longitudinal axis of the autoclave and wherein, in the second compartment, a second agitator rotates counterclockwise and the at least one underflow opening in a second divider separating the second compartment from an adjacent third compartment, is positioned to the left of the longitudinal axis of the autoclave.