AERO-ACOUSTIC MATERIALS PROCESSING APPARATUS AND METHOD

Abstract

The invention is an aero-acoustic comminution apparatus which includes an aero-acoustic comminution machine 10 having a cyclone chamber 12 with an inlet 14 for the material to be comminuted and an inlet 16 for the air. An electric motor 18 coupled to a shaft 20 to which an impeller 22 is coupled rotates the impeller 22 within an impeller housing 24 to draw the air and the entrained material to be comminuted into the cyclone chamber 12 and through an axial inlet system 26 into the impeller 22 and impeller housing 24 and to expel the comminuted material through the impeller housing 24 radially through a transverse outlet. The invention extends to a method of comminuting an ore material using said aero-acoustic comminution apparatus as well as an organic material. The invention further extends to aero-acoustic materials processing plant including said aero-acoustic comminution apparatus and further comprising an enclosure surrounding the aero-acoustic including sound attenuation panels having 4 or more layers which include a plasticised film.

Claims

1.-32. (canceled)

33. An aero-acoustic materials processing plant, comprising an aero-acoustic comminution machine having a cyclone chamber having an inlet for a material to be comminuted and an inlet for an entraining gas and a rotational drive apparatus coupled to rotate an impeller which rotates within an impeller housing to draw the entraining gas and the material to be comminuted into the cyclone chamber and through an axial inlet system into the impeller and impeller housing and to expel the comminuted material through the impeller housing radially through a transverse outlet.

34. The processing plant as claimed in claim 33, comprising an enclosure surrounding the aero-acoustic processing machine, the enclosure constructed to include sound attenuation panels for the reduction of noise, wherein the sound attenuation panels include 4 or more layers which together act to reduce the noise of operation of the machine when heard from outside the enclosure; wherein the sound attenuation panels are in the form of a composite panel constructed of 4 or more layers including; a plasticised film; dense Rockwool; waterproof gyprock; and a rubberised film.

35. The processing plant as claimed in claim 33, wherein the entrained gas inlet is an end opening of the cyclone chamber and is flared with an outer diameter of 0.5 meter to 1.5 meter.

36. The processing plant as claimed in claim 33, wherein the cyclone chamber length is variably adjustable by slidingly displacing a trumpet portion relative to a tubular portion of the cyclone chamber at the open end thereof.

37. The processing plant as claimed in claim 33, wherein the inlet for the material to be comminuted has an inner diameter at its opening where the material to be comminuted is added of between 300 mm and 400 mm and the inner diameter of said intake where the material enters the cyclone chamber is from 325 mm to 375 mm.

38. The processing plant as claimed in claim 33, wherein the gas intake and the intake for the material to be comminuted are made of steel having a wall thickness of from 5 mm to 15 mm.

39. The processing plant as claimed in claim 33, wherein the cyclone chamber has an inner diameter of from 300 mm to 400 mm after the inlet for the material to be comminuted and flares in a flaring zone to a diameter of from 500 mm to 750 mm at the impeller housing.

40. The processing plant as claimed in claim 39, wherein the cyclone chamber increases in diameter from 336 mm at the intake for the material to be comminuted end to 640 mm at the impeller housing end and the flaring zone is from 1500 mm to 2500 mm in length.

41. The processing plant as claimed in claim 33, wherein the impeller housing transverse outlet is from 0.4 square meters to 1.2 square meters.

42. The processing plant as claimed in claim 33, wherein the impeller is a radial fan or blower impeller having a set of impeller vanes secured between two plates, an intake opening being provided on a central zone of one of the plates, the intake opening having a series of fixed vanes distributed around a central hub dimensioned and orientated for inducing a desired flow characteristic as the gas is drawn into the impeller, wherein he impeller vanes are scoop like extending radially from the hub to the periphery of the plates thereby to define the impeller.

43. The processing plant as claimed in claim 33, wherein the impeller is a radial fan or blower impeller having a set of impeller vanes secured between two plates, an intake opening being provided on a central zone of one of the plates, the intake opening having a series of fixed vanes distributed around a central hub dimensioned and orientated for inducing a desired flow characteristic as the gas is drawn into the impeller, wherein he impeller vanes have a flat profile and extend radially from the hub to the periphery of the plates thereby to define the impeller, said vanes being angled at an angle of up to 15 degrees off a center line of the cyclone chamber to promote a more efficient and dispersed particle flow through the impeller.

44. The processing plant as claimed in claim 43, wherein the impeller has an intake diameter of from 0.5 to 0.8 meters, and an outer diameter of 0.75 to 1.1 meters.

45. The processing plant as claimed in claim 44, wherein the impeller is made of steel having a nitrided steel surface to resist wear.

46. A method of comminuting an ore material using an aero-acoustic comminution apparatus including an aero-acoustic comminution machine having a cyclone chamber having an inlet for a material to be comminuted and an inlet for an entraining gas and a rotational drive apparatus coupled to rotate an impeller which rotates within an impeller housing to draw the entraining gas and the material to be comminuted into the cyclone chamber and through an axial inlet system into the impeller and impeller housing and to expel the comminuted material through the impeller housing radially through a transverse outlet, the method including the steps of: drawing ambient air as an entraining gas into the inlet opening of the cyclone chamber to accelerate the air from 0 to 260 m/s; and feeding particulate ore material with a hardness of 10-450 MPa and a particle size characterisation 0-25 mm with a moisture content of 0-65% m/m, said particulate ore being fed into the material inlet at a rate of 0-25 tph; thereby to comminute the ore to particles in the particle characterisation range of 0-500 μm.

47. A method of comminuting an organic material including using an aero-acoustic comminution machine having a cyclone chamber having an inlet for a material to be comminuted and an inlet for an entraining gas and a rotational drive apparatus coupled to rotate an impeller which rotates within an impeller housing to draw the entraining gas and the material to be comminuted into the cyclone chamber and through an axial inlet system into the impeller and impeller housing and to expel the comminuted material through the impeller housing radially through a transverse outlet, the method including the steps of: drawing air as an entraining gas into the inlet opening of the cyclone chamber at ambient conditions; particulate organic material with a particle size characterisation particle size from 0-3000 μm with a moisture content of 0-60% m/m, said particulate material being fed into the material inlet at a rate of 10-15 tph; thereby to comminute the material to particles in the particle characterisation range of 0-500 μm.

48. A method of comminuting an organic material including using an aero-acoustic comminution machine as claimed in claim 47, wherein the comminuted organic material has a moisture content below 10% m/m.

49. The processing plant as claimed in claim 34, wherein the panel is suspended from 10 to 40 mm away from an inner surface of an inner wall of the enclosure to further reduce the transmission of noise.

50. The processing plant as claimed in claim 49, wherein the panel includes a casing perforated on a side which in use faces the inner surface of the inner wall of the enclosure.

51. The processing plant as claimed in claim 50, wherein the panel includes a perforated steel sheet of about 4 mm thickness which in use faces the interior of the enclosure and which has a total aperture ratio of 35% with the apertures being typically 4 mm equivalent diameter.

52. The processing plant as claimed in claim 51, wherein the casing is made of metal and is 100 mm deep.

Description

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0065] The invention will now be described by way of non-limiting examples with reference to the accompanying diagrammatic drawings. In the drawings,

[0066] FIG. 1 shows an aero-acoustic comminution apparatus including an aero-acoustic comminution machine;

[0067] FIG. 2 shows a cross section of a portion of the cyclone chamber having an inlet for the material to be comminuted and an inlet for the entraining gas of the machine of FIG. 1;

[0068] FIG. 3 shows the impeller of the machine of FIG. 1;

[0069] FIG. 4 shows another version of an impeller of the machine of FIG. 1;

[0070] FIG. 5 shows particle size data for iron ore; and

[0071] FIG. 6 shows particle size distribution for lignite.

[0072] In FIGS. 1 to 3, an aero-acoustic comminution apparatus includes an aero-acoustic comminution machine 10 having a cyclone chamber 12 with an inlet 14 for the material to be comminuted and an inlet 16 for the air. An electric motor 18 coupled to a shaft 20 to which an impeller 22 is coupled rotates the impeller 22 within an impeller housing 24 to draw the air and the entrained material to be comminuted into the cyclone chamber 12 and through an axial inlet system 26 into the impeller 22 and impeller housing 24 and to expel the comminuted material through the impeller housing 24 radially through a transverse outlet.

[0073] The length of the cyclone chamber, and thus the air inlet position, is variably adjustable by slidingly displacing a trumpet portion 28 relative to a tubular portion of the cyclone chamber 12 at the open end thereof. The air inlet 16 may have a diameter of 1 m at the trumpet portion 28 edge 32.

[0074] The flat tangential angle A of the inlet pipe 14 allows material to enter the intense vortex airflow in the cyclone 12 with minimum disruption to vortex that exists in the center of the cyclone 12. The inlet pipe 14 can be set to an angle A of 17 degrees to the centre line 34 to allow the particles to be processed to accelerate to over 200 mps while still in the inlet pipe 14 causing minimum effect on the air speed or the vortex forces of the cyclone 12.

[0075] The material to be comminuted inlet into the cyclone chamber 12 is angled at 17 degrees in the direction of flow of the entraining air relative the longitudinal axis centre line 34 of the cyclone chamber 12 and at between the 9 o'clock and 12 o'clock position into the cyclone chamber 12 when viewed axially. The inner diameter of said intake 14 at its opening where the material to be comminuted is added is typically 356 mm. The inner diameter of said intake where the material enters the cyclone chamber 12 is typically 336 mm.

[0076] The air intake 16 and the material intake 14 are made of steel having a wall thickness of typically 10 mm. The intakes are typically pipe.

[0077] The cyclone chamber 12 has an inner diameter of 336 mm at the material inlet 14 end and increases to 640 mm at the impeller housing 24 end i.e. it flares towards the impeller housing 24.

[0078] The impeller housing 24 has an internal surface (not shown) with an asymmetrical configuration so that the gap between the impeller 22 and the housing 24 is not constant around the circumference of the impeller 22. Thus, in use, the gap between the impeller 22 and the internal surface of the impeller housing 24 varies over its extent.

[0079] The linear velocity of the air flowing through the cyclone chamber 12 at its impeller 22 end may be from 230 to 260 m/s.

[0080] The impeller housing 24 transverse outlet is typically about 0.55 square meters (0.74×0.74 meters).

[0081] The impeller 22 shown in FIG. 3, is a radial fan impeller having a set of impeller vanes 40 secured between two plates 42, an intake opening 44 being provided on a central zone of one of the plates 42, the intake opening 44 having a series of fixed vanes 46 distributed around a central hub 48 dimensioned and orientated for inducing a desired flow characteristic as the gas is drawn into the impeller 22. The impeller vanes 40 in this embodiment are scoop like extending radially from the hub 48 to the periphery of the plates 42 thereby to define the impeller 22.

[0082] The impeller 22 has an intake diameter of from typically 0.6096 meters (24″) and an outer diameter of typically 0.9144 meters (36″).

[0083] The impeller 22 of this embodiment is made of steel having a nitrided steel surface to resist wear.

[0084] The impeller 22 has a rotation speed of from 3300 to 3500 rpm but the speed of rotation will depend on the material being comminuted.

[0085] The embodiment of impeller 50 shown in FIG. 4, is a radial fan impeller having a set of impeller vanes 52 secured between two plates 54, an intake opening 56 being provided on a central zone of one of the plates 54, the intake opening 56 having a series of fixed vanes 58 distributed around a central hub 60 dimensioned and orientated for inducing a desired flow characteristic as the gas is drawn into the impeller. The vanes 52 in this embodiment have a flat profile and are angled at an angle B of up to 15 degrees off the center line 62 of the shaft 20 to promote a more efficient and dispersed particle flow through the impeller 50. This also reduces the stress and pressure on the metal vanes 52, and the wear on the surface of the vanes 52.

[0086] In FIG. 5 particle size characterisation data for iron order processed by the apparatus of the invention is shown. The iron ore was fed into the apparatus at a rate of 24 tph at a particle size of below 28 mm and a hardness of about 320 MPa with different impeller rotation speeds as indicated on the figure. As can be seen, at higher impeller RPM smaller particle size characterisations were obtained.

[0087] In FIG. 6, a particle size characterisation was carried out for lignite again at different impeller speeds. Again, the effect of the higher impeller speed can be seen.

[0088] What can be seen from both FIGS. 5 and 6 is that the apparatus of the invention is effective in comminuting both very hard materials, such as ore, and more fragile softer materials such as lignite.