Method of fragmenting and/or weakening of material by means of high voltage discharges

Abstract

A method of fragmenting and/or weakening of material is provided that utilizes high voltage discharges. The material is together with a process liquid introduced into a process area, in which two electrodes face each other at a distance, and is arranged therein in such a manner that the area between the two electrodes is filled with the material and process liquid. Between the two electrodes high voltage discharges are generated for fragmenting or weakening of the material. During the fragmenting or weakening, respectively, of the material, process liquid is discharged from the process area and process liquid is fed into the process area. The process liquid which is fed has a lower electrical conductivity than the process liquid which is discharged.

Claims

1. A method of fragmenting or weakening of material by high voltage discharges, comprising the steps: a) providing a process area having a high voltage discharge gap formed between two electrodes which face each other at a distance; b) feeding the material that is to be fragmented or weakened and a process liquid into the process area in such a way that in the intended fragmentation or weakening operation the area between the two electrodes is filled with the material that is to be fragmented or weakened and the process liquid; and c) fragmenting or weakening the material in the process area by generating high voltage discharges between the two electrodes; d) discharging process liquid from the process area and feeding process liquid into the process area during the fragmenting or weakening of the material, wherein the fed process liquid has a lower electrical conductivity than the discharged process liquid; e) determining a value of at least one of: an electrical conductivity of the process liquid which is present in the process area, an electrical conductivity of the discharged process liquid, or a discharging resistance between the two electrodes; and f) changing, in dependence of the determined value, at least one of: the feeding of the process liquid into the process area or conditioning of the process liquid.

2. The method according to claim 1, wherein the electrical conductivity of the fed process liquid is in a range between 0.2 micro-Siemens per cm and 5000 micro-Siemens per cm.

3. The method according to claim 1, wherein the discharging and feeding of the process liquid takes place simultaneously.

4. The method according to claim 1, wherein the fed and discharged process liquids have volumes that are substantially identical.

5. The method according to claim 1, wherein the feeding and discharging of the process liquid takes place continuously or in intervals.

6. The method according to claim 1, further comprising: conditioning the discharged process liquid to reduce the electrical conductivity thereof; and completely or partially feeding the conditioned discharged process liquid back into the process area.

7. The method according to claim 6, wherein conditioning the discharged process liquid comprises conditioning by at least one of: withdrawal of ions, dilution with process liquid of lower electrical conductivity, withdrawal of fines, changing of a pH-value thereof, or adding of complexing agents.

8. The method according to claim 6, wherein: discharging the process liquid from the process area comprises circulating the discharged process liquid into a process liquid treatment plant, conditioning the discharged process liquid comprises conditioning the discharged process liquid in the process liquid treatment plant, and completely or partially feeding the conditioned discharged process liquid back into the process area comprises completely or partially feeding the conditioned discharged process liquid back into the process area from the liquid treatment plant.

9. The method according to claim 1, wherein the feeding of the process liquid into the process area comprises feeding the process liquid into a reaction zone between the two electrodes.

10. The method according to claim 1, wherein the feeding and discharging of the process liquid takes place in such a way that the fed process liquid passes through a reaction zone between the two electrodes.

11. The method according to claim 10, wherein the fed process liquid passes through the reaction zone between the two electrodes (a) from top to bottom, (b) from bottom to top, or (c) in a direction from a center of the reaction zone radially outwards.

12. The method according to claim 1, wherein the feeding of the process liquid takes place via one of the two electrodes or via both of the two electrodes.

13. The method according to claim 12, wherein the feeding of the process liquid comprises feeding of the process liquid via one or several feeding openings arranged on a face of the one of the two electrodes or faces of both of the two electrodes.

14. The method according to claim 13, wherein the feeding of the process liquid to the feeding openings takes place via a central feeding bore hole inside the one of the two electrodes or via central feeding bore holes inside both of the two electrodes.

15. The method according to claim 13, wherein the feeding of the process liquid comprises feeding of the process liquid via at least one of: a central feeding opening or several feeding openings arranged concentrically around a center of at least one of the two electrodes.

16. The method according to claim 12, wherein the two electrodes comprise one or two rod-shaped electrodes and the feeding of the process liquid comprises feeding of the process liquid via one or several feeding openings arranged around a circumference of the one rod-shaped electrode or around circumferences of the two rod-shaped electrodes.

17. The method according to claim 16, wherein the feeding of the process liquid comprises feeding of the process liquid via several feeding openings equally distributed over a circumference of at least one of the two electrodes.

18. The method according to claim 1, wherein at least one of the two electrodes is surrounded by an isolator and the feeding of the process liquid takes places via the isolator.

19. The method according to claim 18, wherein the feeding of the process liquid takes places via one or several feeding openings arranged on a face of the isolator.

20. The method according to claim 19, wherein the feeding of the process liquid comprises feeding of the process liquid via several feeding openings arranged concentrically around a center of the electrode at the isolator.

21. The method according to claim 1, wherein the feeding of the process liquid takes place via a concentric arrangement or arrangements of feeding orifices, which surround one or both of the two electrodes or an isolator extending therearound concentrically.

22. The method according to claim 1, wherein the feeding of the process liquid takes place via at least one annular gap, which concentrically surrounds at least one of the two electrodes or an isolator extending therearound.

23. The method according to claim 1, wherein providing the process area comprises arranging the two electrodes in a vertically stacked orientation, wherein a lower electrode in the vertically stacked orientation is disposed at a bottom of the process area.

24. The method according to claim 23, wherein the feeding of the process liquid takes place via one or several feeding openings arranged at the bottom of the process area.

25. The method according to claim 23, wherein the discharging of the process liquid takes place via one or several discharging openings arranged at the bottom of the process area.

26. The method according to claim 23, further comprising withdrawing fragmented or weakened material from the process area via one or several withdrawing openings arranged at the bottom of the process area.

27. The method according to claim 1, wherein the providing of the process area comprises arranging the two electrodes laterally adjacent one another, wherein both of the two electrodes comprise an isolator and are charged with a potential unequal to ground potential.

28. The method according to claim 1, further comprising withdrawing fragmented or weakened material from the process area, and wherein the discharging of the process liquid from the process area and the withdrawing of the fragmented or weakened material from the process area utilizes different openings.

29. The method according to claim 1, further comprising: feeding the material that is to be fragmented or weakened continuously or batch-wise, to the process area; and discharging fragmented or weakened material continuously or batch-wise, from the process area.

30. The method according to claim 1, wherein water is used as the process liquid.

31. The method according to claim 1, wherein fragmenting or weakening the material comprises fragmenting or weakening a precious metal ore or semiprecious metal ore.

32. The method according to claim 31, wherein fragmenting or weakening the precious metal ore or semiprecious metal ore comprises fragmenting or weakening a copper ore or a copper/gold ore.

33. The method according to claim 1, further comprising performing a comminution of the fragmented or weakened material.

34. The method according to claim 33, further comprising performing a mechanical comminution of the fragmented or weakened material.

35. A method for fragmenting or weakening of material by high voltage discharges, comprising the steps: a) providing a process area having a high voltage discharge gap formed between two electrodes which face each other at a distance; b) feeding the material that is to be fragmented or weakened, continuously or batch-wise, and a process liquid into the process area in such a way that in the intended fragmentation or weakening operation the area between the two electrodes is filled with the material that is to be fragmented or weakened and the process liquid; c) fragmenting or weakening the material in the process area by generating high voltage discharges between the two electrodes; d) discharging fragmenting or weakened material, continuously or batch-wise, from the process area; e) processing at least a part of the material which is discharged from the process area outside of the process area before feeding the at least a part of the material back into the process area, the processing comprising rinsing the material with a rinsing liquid; and f) determining an electrical conductivity of the rinsing liquid; and g) changing, in dependency of the determined electrical conductivity, at least one of: feeding of the rinsing liquid or conditioning of the rinsing liquid.

36. The method according to claim 35, wherein between an end of the rinsing of the material with the rinsing liquid and either the feeding the rinsed material back into the process area or charging of the material with high voltage discharges in the process area, less than 5 minutes pass.

37. The method according to claim 35, wherein the rinsing liquid is similar to the process liquid which is fed into the process area.

38. The method according to claim 35, further comprising: circulating the rinsing liquid in a circuit; and continuously or temporarily conditioning the rinsing liquid by at least one of: withdrawal of ions, dilution with process liquid of lower conductivity, withdrawal of fines, changing of a pH-value thereof, or adding of complexing agents.

39. The method according to claim 35, further comprising: separating the material discharged from the process area into coarse material and fines; and feeding only the coarse material back into the process area.

40. The method according to claim 39, wherein an amount of the coarse material is larger than an amount of the fines.

41. The method according to claim 35, wherein fragmenting or weakening the material comprises fragmenting or weakening rock material or ore.

42. The method according to claim 35, wherein the rinsing liquid has a lower conductivity than the process liquid which is present in the process area.

43. The method according to claim 35, wherein the conditioning of the rinsing liquid is controlled.

44. A method of fragmenting or weakening of material by high voltage discharges, comprising the steps: a) providing a process area having a high voltage discharge gap formed between two electrodes which face each other at a distance; b) feeding a material that is to be fragmented or weakened and a process liquid into the process area in such a way that an area between the two electrodes is filled with the material that is to be fragmented or weakened and the process liquid; c) fragmenting or weakening the material in the process area by generating high voltage discharges between the two electrodes; d) rinsing the material which is fed into the process area antecedent to the fragmenting or weakening with a rinsing liquid; e) determining an electrical conductivity of the rinsing liquid; and f) changing, in dependency of the determined electrical conductivity, at least one of: feeding of the rinsing liquid or conditioning of the rinsing liquid.

45. The method according to claim 44, wherein the rinsing with the rinsing liquid takes place inside or outside of the process area.

46. The method according to claim 45, wherein the rinsing with the second rinsing liquid takes places outside of the process area and wherein between an end of the rinsing of the material with the rinsing liquid and either the feeding of the rinsed material back into the process area or charging of the material with high voltage discharges in the process area, less than 5 minutes pass.

47. The method according to claim 44, wherein the rinsing liquid is similar to the process liquid which is present in the process area during fragmenting or weakening.

48. The method according to claim 44, further comprising: circulating the rinsing liquid in a circuit; and continuously or temporarily conditioning the rinsing liquid by at least one of: withdrawal of ions, dilution with process liquid of lower conductivity, withdrawal of fines, changing a pH-value thereof, or adding of complexing agents.

49. The method according to claim 44, wherein fragmenting or weakening the material comprises fragmenting or weakening rock material or ore.

50. The method according to claim 44, wherein the rinsing liquid has a lower conductivity than the process liquid which is present in the process area.

51. The method according to claim 44, wherein the conditioning of the rinsing liquid is controlled.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further embodiments, advantages and applications of the invention result from the dependent claims and from the following description on the basis of the drawings. Therein show:

(2) FIG. 1 a vertical section through a part of a first process vessel according to the invention during the conducting of a method according to the invention;

(3) FIG. 2 a vertical section through a part of a first high voltage electrode according to the invention;

(4) FIG. 3 a vertical section through a part of a second high voltage electrode according to the invention;

(5) FIG. 4 a vertical section through a part of a third high voltage electrode according to the invention;

(6) FIG. 5 a vertical section through a part of a fourth high voltage electrode according to the invention;

(7) FIG. 6 a vertical section through a part of a fifth high voltage electrode according to the invention;

(8) FIG. 7 a vertical section through a part of a second process vessel according to the invention;

(9) FIG. 8 a vertical section through a part of a third process vessel according to the invention;

(10) FIG. 9 a vertical section through a part of a fourth process vessel according to the invention

(11) FIG. 10 a vertical section through a part of a fifth process vessel according to the invention; and

(12) FIG. 11 a vertical section through a process area according to the invention having two reaction zones.

MODES FOR CARRYING OUT THE INVENTION

(13) FIG. 1 shows the lower part of a first process vessel according to the invention in vertical section during the conducting of a method according to the invention.

(14) As can be seen, the process vessel forms a closed process area 2 according to the invention, at the bottom of which an electrode 4 is arranged, which is on ground potential. The process area 2 is approximately half filled (see liquid level S) with a process liquid 5, in the present case water. The funnel-shaped bottom of the process area 2 is covered with a filling of material 1 that is to be fragmented, in the present case pieces of rock. From above, a rod-shaped high voltage electrode 3 according to the invention extends into the process area 2.

(15) As can be seen in combination with FIG. 2, which shows the front part of the high voltage electrode 3 in a detailed sectional representation, the part of the high voltage electrode 3 which is visible here is formed by an isolator body 8 with a central conductor 14, at the end of which, which end axially protrudes out of the isolator body 8, a rod-shaped electrode tip 15 is arranged. The central conductor 14 or the electrode tip 15 which forms its working side end, respectively, comprises in the area directly adjacent to the working end sided front face of the isolator body 8 at its outer circumference a circumferential radial ridge 16, which serves as field relief. The electrode tip 15 and the ridge 16 are commonly formed as a one-piece exchange part made of stainless steel, which by means of an inner thread 19 that is formed at the end of an anti-fatigue sleeve 20, is threaded onto an outer thread 21 of a tension rod 22, which extends inside the central conductor 14, in such a way that the front face of the ridge 16 which is facing towards the isolator body 8 abuts under compressive pre-stress against the working end sided front face of the central conductor 14.

(16) The high voltage electrode 3 dips with its electrode tip 15 into the filling of pieces of rock 1, which is present at the bottom of the process area 2, in such a way that between the front face of the electrode tip 15 of the high voltage electrode 3 and the front face of the bottom electrode 4 there remains an area (reaction zone) which is filled with pieces of rock 1 and process liquid 5.

(17) At its front face which is facing away from the isolator body 8, the ridge 16 comprises several feeding openings 6 for process liquid 5 which are with an equal angular pitch arranged concentrically around the centre of the electrode, which openings are continuously fed with process liquid 5 from the non-working end of the high voltage electrode 3 via a central feeding channel 7 which extends in the centre of the tension rod 22 and through the anti-fatigue sleeve 20 (see arrows). By this, continuously fresh process liquid is fed into the reaction zone R, in which by charging the high voltage electrode 3 with high voltage pulses, high voltage discharges are generated between the bottom electrode 4 and the high voltage electrode 3, and by doing so, old process liquid 5 and fines are displaced out of the reaction zone R. At the same time, the same amount of process liquid is discharged from the process area 2 via radial discharging openings 12 above the reaction zone R (see arrows) and is fed to a process liquid treatment plant (not shown), in which the particle load is removed and the electrical conductivity of the process liquid 5 is reduced. The process liquid 5 treated in this way is, via the feeding openings 6 in the high voltage electrode 3, fed back into the process area 2. In this way, a process liquid circuit is formed by which the reaction zone continuously is flushed with reprocessed process liquid 5.

(18) FIG. 3 shows a vertical section through the working sided end of a second high voltage electrode 3 according to the invention, which differs from the one shown in FIG. 2 merely in that the feeding openings 6 for the process liquid 5 are not arranged at the face of the ridge 16 but at the circumference of the rod-shaped electrode tip 15.

(19) FIG. 4 shows a vertical section through the working sided end of a third high voltage electrode 3 according to the invention, which differs from the one shown in FIG. 2 in that there are not arranged several feeding openings 6 for the process liquid 5 at the face of the ridge 16 but that merely one central feeding opening 6 is arranged at the face of the rod-shaped electrode tip 15.

(20) FIG. 5 shows a vertical section through the working sided end of a fourth high voltage electrode 3 according to the invention, which generally differs from the high voltage electrodes 3 shown in the FIGS. 2, 3 and 4 in that the feeding openings 6 are not formed by the central conductor 14 or the electrode tip 15, respectively, but are formed by the isolator body 8, at the working sided face of which several feeding channels 7 end thereby forming feeding openings 6. The central conductor 14 in the present case is designed as solid metal rod and, in the area where it at the working end side protrudes out of the isolator body 8, forms at its outer circumference a circumferential radial ridge 16, which also here serves as field relief. The electrode tip 15 again is designed as exchange part, however here in the form of an anti-fatigue bolt 23, which by means of an end-sided outer thread 21 is screwed into an inner thread 19 in the central conductor 14 and by means of a nut 24, which is screwed onto its end which is forming the electrode tip 15, under compressive pre-stress abuts against the face of the central conductor 14.

(21) FIG. 6 shows a vertical section through the working sided end of a fifth high voltage electrode 3 according to the invention, which differs from the one shown in FIG. 5 in that the isolator body 8 of the electrode 3 is surrounded by a bushing like component 17 which covers a part of its working end sided face and together with the isolator body 8 form an annular gap 10, which from the non-working end of the high voltage electrode 3 can, via the feeding channels 7, be fed with process liquid.

(22) The electrode tip 15 is formed here from a cap nut 25, which by means of an anti-fatigue bolt 23 that is screwed into same is fastened in a tapped blind hole in the face of the central conductor 14 and under compressive pre-stress abuts against this face of the central conductor 14. As can be seen, a further difference with respect to the high voltage electrode shown in FIG. 5 consists in that the central conductor 14 here in the area where it exits the isolator body 8 does not form a ridge.

(23) FIG. 7 shows the lower part of a second process vessel according to the invention in vertical section. The process vessel shown here differs from the one shown in FIG. 1 merely in that for the feeding of the process liquid there is not used a high voltage electrode with feeding openings but an arrangement of feeding orifices 9, which are arranged above the reaction zone R evenly distributed at the boundary walls of the process vessel and in the intended use in each case generate a process liquid jet which is directed towards the bottom electrode 4 (see arrows). The discharging of the process liquid in the intended use takes place, as in the process vessel shown in FIG. 1, via radial discharge openings 12 above the reaction zone R (see arrows).

(24) FIG. 8 shows the lower part of a third process vessel according to the invention in vertical section. In the process vessel shown here, in the intended use the feeding of process liquid takes place via (not shown) feeding openings from above. The bottom electrode 4 is carried by a thieve bottom 26, via which in the intended use process liquid is fed to the actual bottom 27 of the process vessel and via a central discharge opening 12 is discharged. The high voltage electrode 3 is substantially identical to the one of the process vessel of FIG. 7.

(25) FIG. 9 shows a fourth process vessel according to the invention in vertical section. As can be seen, the process vessel here forms a process area 2 according to the invention which is open at the top, at the funnel-shaped bottom of which there is arranged a bottom electrode 4 which comprises a central discharging bore hole 13 for material that has been comminuted to target size. From above, a rod-shaped high voltage electrode 3 projects into the process area 2, which consists of an isolator body 8 with a central conductor 14, at the working end of which, which end axially protrudes out of the isolator body 8, a rod-shaped electrode tip 15 is arranged. The central conductor 14 or the electrode tip 15 forming the working sided end of same, respectively, in the area direct adjacent to the working end sided face of the isolator body 8 at its outer circumference comprises a circumferential radial ridge 16, which serves as field relief. At a location near the bottom electrode 4, the bottom of the process vessel comprises an orifice 11 for the feeding of process liquid, by means of which in the intended use a process liquid stream which is directed towards the reaction zone can be generated (see arrow). At an opposite position, the bottom of the process vessel comprises a discharging opening 12 for process liquid (see arrow).

(26) FIG. 10 shows a fifth process vessel according to the invention in vertical section, which differs from the one shown in FIG. 9 merely in that for the feeding of the process liquid there does not exist a bottom orifice, but a high voltage electrode 3 having feeding openings 6 (see arrows). This high voltage electrode 3 with respect to the arrangement of the feeding openings 6 is identical to the high voltage electrodes shown in the FIGS. 1 and 2.

(27) FIG. 11 shows, in a very schematized manner, a vertical section through a process area 2 according to the invention of a plant for weakening pieces of ore according to the invention, which process area is having two separate reaction zones R. In the process area 2, a vibrating screen deck 28 is arranged, which comprises two electrode areas 4 which are grounded. Above each of the electrode areas 4, in each case at a vertical distance a rod-shaped high voltage electrode 3 is arranged, which with respect to its design is similar to the one shown in the FIGS. 7 and 8. The process area 2 is filled up to half of its height with process liquid 5 (see liquid level S).

(28) In the intended use, pieces of ore that are to be weakened are conveyed, due to a vibrating action of the vibrating screen deck 28, from right to left through the area under the high voltage electrodes 3, while high voltage discharges are generated between the high voltage electrodes 3 and the electrode areas 4. In doing so, in each case the area, in which high voltage discharges take place (reaction zone R), is fed with process liquid 5 via flushing orifices 18 (see arrows). At the same time, at the bottom of the process area 2, the same amount of process liquid 5 is discharged via discharging openings 12 (see arrows) and is fed to a process liquid treatment plant (not shown), in which it is treated and is reduced in its electrical conductivity. The process liquid 5 which has been reprocessed in that way is fed back to the process area 2 via the flushing orifices 18. In this way, also here a process liquid circuit is formed, by means of which the reaction zones R are continuously flushed with reprocessed process liquid 5.

(29) While there are shown and described in the present application text preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.