| THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: A method of processing or refining a mineral ore which includes the following (i) producing a lump size to allow effective operation of at least one pair of rotating members; (ii) passing said lumps of said mineral ore through a space between the at least one pair of rotating members to reduce the size of said lumps; (iii) forwarding the lumps having said reduced size through at least one pair of conveyors wherein said lumps are subject to impaction whereby lumps or particles substantially having a maximum dimension of between 25mm to 150mm are collected; (iv) separating ore lumps which have a lesser specific gravity from impurity lumps by impacting said lumps or particles produced from step (iii) on an impaction surface whereby said impurity lumps having a lesser departure angle than said ore lumps will be discarded; and (v) collecting the ore lumps for further processing. 2. A method as claimed in claim 1 , wherein step (i) further comprises: (a) a regulated size flow wherein said lumps of mineral ore are passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members; or (b) an unregulated size flow wherein said lumps of said mineral ore are pushed from an exit opening of a hopper located above the at least one pair of rotating members. 3. A method as claimed in claim 2, wherein the regulated size flow further comprises said lumps of mineral ore having a size greater than 1200mm are passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members. 4. A method as claimed in claim 2 or claim 3, wherein said impaction conveyors have a belt or chain having a plurality of spaced impact members arranged transversely to a longitudinal axis of each conveyor. 5. A method as claimed in claim 4, wherein the lumps of mineral ore are passed between the pair of impaction conveyors mounted on a pair of frames supported in a structure having a resilient spring arrangement and each frame has adjustment means to align and space apart each frame. 6. A method as claimed in any one of claims 2 to 5, wherein there is an adjustable entrance and exit gap between each impaction conveyor. 7. A method as claimed in claim 2, wherein the unregulated size flow further comprises said lumps of said mineral ore having a size less than 1200mm are pushed from an exit opening of a hopper located above the at least one pair of rotating members. 8. A method as claimed in claim 1 , wherein step (ii) further comprises said at least one pair of rotating members, rotating in the same direction. 9. A method as claimed in claim 6, wherein the at least one pair of rotating members have at least one impaction member extending outwardly from an external surface of each rotating member. 10. A method as claimed in claim 6 or claim 7, wherein the at least one pair of rotating members have impaction members extending outwardly from an external surface of each rotating member which are spaced from each other along a length of each rotating member. 1 1 . A method as claimed in any one of claims 6 to 9, wherein rotation of each rotating member is such that said impaction members on each adjacent rotating member do not contact each other. 12. A method as claimed in claim 9 wherein a rotation speed of each rotating member in the form of a cylinder is set so as to arrange flat surfaces of said lumps in a vertical aspect tangential to a rotating external surface of each cylinder. 13. A method as claimed in claim 10 wherein said at least one impaction member of each cylinder are arranged in pairs extending transversely through each cylinder wherein said pairs of impaction members are arranged in a staggered formation at an angle between 10° to 90Q to each other. 14. A method as claimed in claim 1 1 , wherein said pairs of impaction members are arranged in a staggered formation at an angle of 15° to each other. 15. A method as claimed in any one of claims 6 to 12, wherein there is an adjustable gap between each pair of rotating members. 16. A method as claimed in claim 13 wherein said adjustable gap is set to provide a clearance for lumps having a size of 250mm or less. 17. A method as claimed in any one of claims 8 to 16 wherein lumps of ore passing from one rotating member to another rotating member are separated into stone or impurity lumps and ore lumps. 18. A method as claimed in claim 1 , wherein step (iii) further comprises at least one pair of angled conveyors having a variable aperture or gap therebetween, the variable gap will open and close to accommodate the size of the lump passing therethrough. 19. A method as claimed in claim 18, wherein step (iii) further comprises passing lumps having reduced size between at least one pair of angled conveyors having cleats or grousers oriented transversely thereto whereby a chain on an upper conveyor has a sagging part or angled part which contacts chain rollers on adjacent conveyors which causes removal of impurity lumps whereby said mineral ore lumps pass through an exit gap between each conveyor allowing for mineral ore lumps of 25-50mm to be collected. 20. A method as claimed in claim 18 or claim 19, wherein a chain on an upper conveyor comprises a fixed series of stationary transverse bars fixed in a pre-determined profile to provide a rigid support. 21 . A method as claimed in any one of claims 18 to 20, wherein the at least one pair of angled conveyors each of which further comprises a set of grouser or impaction plates transversely attached to each conveyor. 22. A method as claimed in claim 1 , wherein step (iv) further comprises separating ore lumps which have a lesser specific gravity from impurity lumps using a high throughput rate assembly. 23. A method as claimed in claim 22, wherein said high throughput rate assembly comprises a high speed conveyor having a speed of around 6-8m/sec wherein mineral ore lumps entrained with impurity lumps are impacted against a striker or impact plate wherein the heavier impurity lumps will have a departure angle which is less than a departure angle of the mineral ore lumps so as to separate the impurity lumps from said mineral ore lumps. 24. A method as claimed in claim 23 wherein lumps smaller than 25mm and which have separated from said pair of conveyors are also transferred onto said high speed conveyor. 25. A method as claimed in claim 1 , wherein step (iv) further comprises separating ore lumps which have a lesser specific gravity from impurity lumps using a low throughput rate assembly. 26. A method as claimed in claim 25, wherein said low throughput rate assembly comprises at least one rotating paddle wheel having paddles which are oriented to each other at different angles whereby each of the mineral ore lumps as well as impurity lumps will impact on a striker plate so that each of the mineral ore lumps will have a different departure angle to said impurity lumps thereby facilitating separation thereof. 27. A method as claimed in claim 26, wherein each of the paddles has an open or vented inner end to ensure that deposition of lumps does not occur between each paddle and an adjacent external surface of the at least one paddle wheel. 28. Apparatus for processing or refining a mineral ore comprising: a hopper with an opening for providing a sized lump of mineral ore; at least one pair of rotating members rotating in the same direction to further reduce the size of the mineral ore lump; at least one pair of angled conveyors wherein an entrance gap between each angled conveyor for passage of said mineral ore lumps is of greater size than an exit gap between each angled conveyor for departure of said mineral ore lumps, said mineral ore lumps departing said angled conveyors having a maximum dimension of between 25mm to 150mm; a separating assembly for separating ore lumps which have a lesser specific gravity from impurity lumps; and a collection device for collecting the ore lumps for further processing. 29. An apparatus as claimed in claim 28, wherein the hopper further comprises a pair of impaction conveyors located below the hopper for producing a regulated size lump of mineral ore. 30. An apparatus as claimed in claim 28 or claim 29, and having any of the features of the method of processing or refining a mineral ore according to claims 1 to 27. A method of processing or refining a mineral ore which includes the following (i) passing lumps of said mineral ore through a space between at least one pair of rotating members to reduce the size of said lumps; (ii) forwarding lumps having said reduced size through at least one pair of conveyors where said lumps are subject to impaction whereby lumps or particles substantially having a maximum dimension of between 25mm to 150mm are collected; (iii) separating ore lumps which have a lesser specific gravity from impurity lumps by impacting said lumps or particles produced from step (ii) on an impaction surface whereby said impurity lumps having a lesser departure angle than said ore lumps will be discarded; and (iv) collecting the ore lumps for further processing. 32. A method as claimed in claim 31 wherein step (i) further comprises said lumps of said mineral ore having a size less than 1200mm are pushed from an exit opening of a hopper located above the at least one pair of rotating members. 33. A method as claimed in claim 31 or claim 32, wherein said at least one pair of rotating members rotate in the same direction. 34. A method as claimed in any one of claims 31 to 33, wherein the at least one pair of rotating members have at least one impaction member extending outwardly from an external surface of each rotating member. 35. A method as claimed in claim 31 wherein in step (i) said lumps of mineral ore having a size greater than 1200mm are passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members. 36. A method as claimed in claim 35 wherein said at least one pair of rotating members rotate in the same direction. 37. A method as claimed in claims 35 or 36, wherein the at least one pair of rotating members have impaction members extending outwardly from an external surface of each rotating member which are spaced from each other along a length of each rotating member. 38. A method as claimed in any one of claims 35 to 37, wherein said impaction conveyors have a belt or chain having a plurality of spaced impact members arranged transversely to a longitudinal axis of each conveyor. 39. A method as claimed in either of claim 35 or claim 38, wherein rotation of each rotating member is such that said impaction members on each adjacent rotating member do not contact each other. 40. A method as claimed in claim 39 wherein a rotation speed of each rotating member in the form of a cylinder is set so as to arrange flat surfaces of said lumps in a vertical aspect tangential to a rotating external surface of each cylinder. 41 . A method as claimed in claim 40 wherein impaction members of each cylinder are arranged in pairs extending transversely through each cylinder wherein said pairs of impaction members are arranged in a staggered formation at an angle between 10° to 90Q to each other. 42. A method as claimed in any one of claims 35 to 41 , wherein the lumps of mineral ore are passed between the pair of impaction conveyors mounted on a pair of frames supported in a structure having a resilient spring arrangement and each frame has adjustment means to align and space apart each frame. 43. A method as claimed in claim 42, wherein there is an adjustable entrance and exit gap between each impaction conveyor. 44. A method as claimed in any one of claims 31 to 43, wherein there is an adjustable gap between the at least one pair of rotating members. 45. A method as claimed in claim 44, wherein said adjustable gap set to provide a clearance for lumps having a size of 250mm or less. 46. A method as claimed in claim 45, wherein lumps of ore passing from one rotating member to another rotating member are separated into stone or impurity lumps and ore lumps. 47. A method as claimed in claim 46, wherein after the mineral ore lumps have passed through said adjustable gap they are passed between at least one pair of angled conveyors having cleats or grousers oriented transversely thereto whereby a chain on an upper conveyor has a sagging part or angled part which contacts chain rollers on adjacent conveyors which causes removal of impurity lumps whereby said mineral ore lumps pass through an exit gap between each conveyor allowing for mineral ore lumps of 25-50mm to be collected. 48. A method as claimed in claim 47, wherein a chain on an upper conveyor comprises a fixed series of stationary transverse bars fixed in a pre-determined profile to provide a rigid support 49. A method as claimed in claim 46 or claim 47, wherein there is provided a rotating member having an impaction tyne at an entrance gap between said at least one pair of angled conveyors which impaction tyne will contact said mineral ore lumps before passing through said entrance gap. 50. A method as claimed in any one of claims 47 to 49, wherein said mineral ore lumps after passing through said at least one pair of angled conveyors are transferred to a high speed conveyor having a speed of around 6-8m/sec wherein coal lumps entrained with impurity lumps are impacted against a striker or impact plate wherein the heavier impurity lumps will have a departure angle which is less than a departure angle of the mineral ore lumps so as to separate the impurity lumps from said mineral ore lumps. 51 . A method as claimed in any one of claims 47 to 49, wherein mineral ore lumps after leaving the exit gap between said at least one pair of angled conveyors are passed onto at least one rotating paddle wheel having paddles which are oriented to each other at different angles whereby each of mineral ore lumps as well as impurity lumps will impact on a striker plate so that each of the mineral ore lumps will have a different departure angle to said impurity lumps thereby facilitating separation thereof. 52. A method as claimed in claim 51 , wherein each of the paddles has an open or vented inner end to ensure that deposition of lumps does not occur between each paddle and an adjacent external surface of the at least one paddle wheel. 53. A method as claimed in claim 50 wherein lumps smaller than 25mm and which have separated from said at least one pair of angled conveyors are also transferred onto said high speed conveyor. 54. Sizing or mineral ore lump splitting apparatus having a plurality of rotating members wherein each rotating member has a plurality of impaction tynes or projections normally oriented to an external surface of each rotating member which pass through adjacent impaction tynes or projections on an adjoining rotating member during operation. 55. Apparatus for removal of hard rock and for splitting of mineral ore lumps in a sedimentary plane which include at least one pair of angled conveyors wherein an entrance gap is between each angled conveyor for passage of said mineral ore lumps is of greater size than an exit gap between each angled conveyor for departure of said mineral ore lumps and there is further provided in at least one of said conveyors a sagging or angled part of a chain or belt and each conveyor also includes a multiplicity of rotating rollers which contact said angled chain part to facilitate separation of impurity lumps from said mineral ore lumps. 56. Apparatus as claimed in claim 55 wherein each of the entrance gap and said exit gap are adjustable in size. 57. Apparatus as claimed in claim 55 or claim 56, wherein a conveyor having said angled or sagging chain part is located above an adjacent conveyor. 58. Apparatus as claimed in any one of claims 55 to 57, each of said angled conveyors is provided with a plurality of spaced and transversely oriented cleats or grousers. 59. Apparatus for separation of mineral ore lumps from impurity lumps including a conveyor and a striker or impact plate wherein mineral ore lumps entrained with impurity lumps are transferred to the conveyor and on leaving the conveyor are impacted against a striker or impact plate wherein the heavier impurity particles will have a departure angle that is less than a departure angle for the mineral ore particles facilitating separation of said impurity particles from said mineral ore particles. 60. Apparatus for separation of mineral ore lumps from impurity lumps having one or more rotating paddle wheels having paddles or projections which are oriented to each other at different angles as well as a striker or impact plate whereby impurity lumps entrained with mineral ore lumps are transferred to said one or more rotating paddle wheels and upon leaving said paddle wheel(s) impact on said striker or impact plate wherein impurity lumps will have a different departure angle to said mineral ore lumps thereby facilitating their separation. 61 . Mineral ore processing plant including the apparatus of claim 54, claim 55, claim 59 or claim 60. |
FIELD OF THE INVENTION This invention relates to an improved mineral ore processing method and an apparatus for the processing of a mineral ore. This invention has particular application to the processing of such mineral ore to remove sedimentary impurities such as mudstone, claystone, siltstone, and sandstone, igneous rock impurities such as siderite and dolerite or the like.
This invention relates particularly to an improved mineral ore processing method and an apparatus for the processing of a mineral ore that is a coal ore or a metalliferous ore. It will therefore be convenient to hereinafter describe the invention with reference to this example application. However it is to be clearly understood that the invention is capable of wider application.
BACKGROUND TO THE INVENTION
Considerable energy is required to fracture and size sedimentary materials when flat sedimentary surfaces are crushed together between jaws or rolls. This is the case because the material flow pattern through various conventional crushing and/or sizing machines commonly presents these large flat surfaces to the working faces of the machines. These machines are typically jaw crushers, roll crushers and their derivatives which squeeze lumps sufficiently to exceed their unconfined compressive strength (UCS).
Prior art crushing action produces fines when flat faces are crushed toward each other. Each crush produces a large proportion of very fine particles of both coal and waste material as compared to the previously undisturbed lump. This provides considerable problems in regard to removal of such very fine particles.
Reference may be made to prior art which includes US Patent 4592516, US Patent 5976224 and US Patent 5340481 .
US Patent 4592516 refers to a pair of accelerator rotors for impacting coal particles which are spaced from each other and separated by an inclined splitting or impaction grate. This process is not designed for splitting coal particles along their sedimentary planes and as such will include impurity particles when the processed coal particles fall into collection chutes located below the pair of accelerator rotors.
US Patent 5976224 refers to a process of coal particles being separated on the basis of different rotational velocities and specific gravities into different flow paths. This process is mainly directed at the separation of flyash from unburnt carbon and thus is not designed for separating coal particles along their sedimentary planes and thus would be inefficient in this regard. US Patent 5340481 refers to separation of raw coal in slurry form where lighter particles are separated from heavier particles on the basis of travel within a dense media cyclone wherein the lighter particles are forced towards the centre of the cyclone and the heavier particles houses an internal surface of the cyclone. The same comments apply to this reference as are made above in relation to US Patents 4592516 and 5976224.
Clearly it would be advantageous if a contrivance could be devised to provide a mineral ore processing apparatus as well as a mineral ore processing method which is efficient in operation and which alleviates to at least some extent disadvantages using crushing and/or sizing machines of the type described immediately above.
SUMMARY OF THE INVENTION
According to a first aspect, the present invention provides a method of processing or refining a mineral ore which includes the following steps:
(i) producing a lump size to allow effective operation of at least one pair of rotating members;
(ii) passing said lumps of said mineral ore through a space between the at least one pair of rotating members to reduce the size of said lumps;
(iii) forwarding the lumps having said reduced size through at least one pair of conveyors wherein said lumps are subject to impaction whereby lumps or particles substantially having a maximum dimension of between 25mm to 150mm are collected;
(iv) separating ore lumps which have a lesser specific gravity from impurity lumps by impacting said lumps or particles produced from step (iii) on an impaction surface whereby said impurity lumps having a lesser departure angle than said ore lumps will be discarded; and (v) collecting the ore lumps for further processing.
Step (i) may further comprise: (a) a regulated size flow wherein said lumps of mineral ore are passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members; or (b) an unregulated size flow wherein said lumps of said mineral ore are pushed from an exit opening of a hopper located above the at least one pair of rotating members. The regulated size flow may further comprise said lumps of mineral ore having a size greater than 1200mm are passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members. Said impaction conveyors may have a belt or chain having a plurality of spaced impact members arranged transversely to a longitudinal axis of each conveyor.
The lumps of mineral ore may be passed between the pair of impaction conveyors mounted on a pair of frames supported in a structure having a resilient spring arrangement and each frame has adjustment means to align and space apart each frame.
There may be an adjustable entrance and exit gap between each impaction conveyor. The unregulated size flow may further comprise said lumps of said mineral ore having a size less than 1200mm are pushed from an exit opening of a hopper located above the at least one pair of rotating members.
Step (ii) may further comprise said at least one pair of rotating members, rotating in the same direction.
The at least one pair of rotating members may have at least one impaction member extending outwardly from an external surface of each rotating member.
The at least one pair of rotating members may have impaction members extending outwardly from an external surface of each rotating member which are spaced from each other along a length of each rotating member. Rotation of each rotating member may be such that said impaction members on each adjacent rotating member do not contact each other. A rotation speed of each rotating member in the form of a cylinder may be set so as to arrange flat surfaces of said lumps in a vertical aspect tangential to a rotating external surface of each cylinder.
Said at least one impaction member of each cylinder may be arranged in pairs extending transversely through each cylinder wherein said pairs of impaction members are arranged in a staggered formation at an angle between 10° to 90 Q to each other.
Said pairs of impaction members may be arranged in a staggered formation at an angle of 15° to each other.
There may be an adjustable gap between each pair of rotating members.
Said adjustable gap may be set to provide a clearance for lumps having a size of 250mm or less.
Lumps of ore passing from one rotating member to another rotating member may be separated into stone or impurity lumps and ore lumps.
Step (iii) may further comprise at least one pair of angled conveyors having a variable aperture or gap therebetween, the variable gap will open and close to accommodate the size of the lump passing therethrough.
Step (iii) may further comprise passing lumps having reduced size between at least one pair of angled conveyors having cleats or grousers oriented transversely thereto whereby a chain on an upper conveyor has a sagging part or angled part which contacts chain rollers on adjacent conveyors which causes removal of impurity lumps whereby said mineral ore lumps pass through an exit gap between each conveyor allowing for mineral ore lumps of 25-50mm to be collected.
A chain on an upper conveyor may comprise a fixed series of stationary transverse bars fixed in a pre-determined profile to provide a rigid support. The at least one pair of angled conveyors each of which may further comprise a set of grouser or impaction plates transversely attached to each conveyor.
Step (iv) may further comprise separating ore lumps which have a lesser specific gravity from impurity lumps using a high throughput rate assembly.
Said high throughput rate assembly may comprise a high speed conveyor having a speed of around 6-8m/sec wherein mineral ore lumps entrained with impurity lumps are impacted against a striker or impact plate wherein the heavier impurity lumps will have a departure angle which is less than a departure angle of the mineral ore lumps so as to separate the impurity lumps from said mineral ore lumps.
Lumps smaller than 25mm and which have separated from said pair of conveyors may also be transferred onto said high speed conveyor.
Step (iv) may further comprise separating ore lumps which have a lesser specific gravity from impurity lumps using a low throughput rate assembly.
Said low throughput rate assembly may comprise at least one rotating paddle wheel having paddles which are oriented to each other at different angles whereby each of the mineral ore lumps as well as impurity lumps will impact on a striker plate so that each of the mineral ore lumps will have a different departure angle to said impurity lumps thereby facilitating separation thereof. Each of the paddles may have an open or vented inner end to ensure that deposition of lumps does not occur between each paddle and an adjacent external surface of the at least one paddle wheel.
According to a further aspect, the present invention provides an apparatus for processing or refining a mineral ore comprising:
a hopper with an opening for providing a sized lump of mineral ore;
at least one pair of rotating members rotating in the same direction to further reduce the size of the mineral ore lump;
at least one pair of angled conveyors wherein an entrance gap between each angled conveyor for passage of said mineral ore lumps is of greater size than an exit gap between each angled conveyor for departure of said mineral ore lumps, said mineral ore lumps departing said angled conveyors having a maximum dimension of between 25mm to 150mm;
a separating assembly for separating ore lumps which have a lesser specific gravity from impurity lumps; and
a collection device for collecting the ore lumps for further processing.
The hopper may further comprise a pair of impaction conveyors located below the hopper for producing a regulated size lump of mineral ore. The apparatus for processing or refining a mineral ore may have any of the features of the method of processing or refining a mineral ore according to the first aspect.
According to a further aspect, the present invention provides a method of processing or refining a mineral ore which includes the following steps:
(i) passing lumps of said mineral ore through a space between at least one pair of rotating members to reduce the size of said lumps;
(ii) forwarding lumps having said reduced size through at least one pair of conveyors where said lumps are subject to impaction whereby lumps or particles substantially having a maximum dimension of between 25mm to 150mm are collected;
(iii) separating ore lumps which have a lesser specific gravity from impurity lumps by impacting said lumps or particles produced from step (ii) on an impaction surface whereby said impurity lumps having a lesser departure angle than said ore lumps will be discarded; and
(iv) collecting the ore lumps for further processing.
Step (i) may further comprise said lumps of said mineral ore having a size less than 1200mm are pushed from an exit opening of a hopper located above the at least one pair of rotating members.
Said at least one pair of rotating members may rotate in the same direction.
The at least one pair of rotating members may have at least one impaction member extending outwardly from an external surface of each rotating member. Step (i) said lumps of mineral ore having a size greater than 1200mm may be passed from an exit opening of a hopper to a pair of impaction conveyors located below the hopper before said lumps of mineral ore are passed between said at least one pair of rotating members.
Said at least one pair of rotating members may rotate in the same direction.
The at least one pair of rotating members may have impaction members extending outwardly from an external surface of each rotating member which are spaced from each other along a length of each rotating member.
Said impaction conveyors may have a belt or chain having a plurality of spaced impact members arranged transversely to a longitudinal axis of each conveyor. Rotation of each rotating member may be such that said impaction members on each adjacent rotating member do not contact each other.
A rotation speed of each rotating member in the form of a cylinder may be set so as to arrange flat surfaces of said lumps in a vertical aspect tangential to a rotating external surface of each cylinder.
Impaction members of each cylinder may be arranged in pairs extending transversely through each cylinder wherein said pairs of impaction members are arranged in a staggered formation at an angle between 10° to 90 Q to each other.
The lumps of mineral ore may be passed between the pair of impaction conveyors mounted on a pair of frames supported in a structure having a resilient spring arrangement and each frame has adjustment means to align and space apart each frame. There may be an adjustable entrance and exit gap between each impaction conveyor.
There may be an adjustable gap between the at least one pair of rotating members. Said adjustable gap may be set to provide a clearance for lumps having a size of 250mm or less.
Lumps of ore passing from one rotating member to another rotating member may be separated into stone or impurity lumps and ore lumps.
After the mineral ore lumps have passed through said adjustable gap they may be passed between at least one pair of angled conveyors having cleats or grousers oriented transversely thereto whereby a chain on an upper conveyor has a sagging part or angled part which contacts chain rollers on adjacent conveyors which causes removal of impurity lumps whereby said mineral ore lumps pass through an exit gap between each conveyor allowing for mineral ore lumps of 25-50mm to be collected.
A chain on an upper conveyor may comprise a fixed series of stationary transverse bars fixed in a pre-determined profile to provide a rigid support
There may be provided a rotating member having an impaction tyne at an entrance gap between said at least one pair of angled conveyors which impaction tyne will contact said mineral ore lumps before passing through said entrance gap.
Said mineral ore lumps after passing through said at least one pair of angled conveyors may be transferred to a high speed conveyor having a speed of around 6- 8m/sec wherein coal lumps entrained with impurity lumps are impacted against a striker or impact plate wherein the heavier impurity lumps will have a departure angle which is less than a departure angle of the mineral ore lumps so as to separate the impurity lumps from said mineral ore lumps.
Mineral ore lumps after leaving the exit gap between said at least one pair of angled conveyors may be passed onto at least one rotating paddle wheel having paddles which are oriented to each other at different angles whereby each of mineral ore lumps as well as impurity lumps will impact on a striker plate so that each of the mineral ore lumps will have a different departure angle to said impurity lumps thereby facilitating separation thereof.
Each of the paddles may have an open or vented inner end to ensure that deposition of lumps does not occur between each paddle and an adjacent external surface of the at least one paddle wheel. Lumps smaller than 25mm and which have separated from said at least one pair of angled conveyors may be transferred onto said high speed conveyor. According to a further aspect, the present invention provides a sizing or mineral ore lump splitting apparatus having a plurality of rotating members wherein each rotating member has a plurality of impaction tynes or projections normally oriented to an external surface of each rotating member which pass through adjacent impaction tynes or projections on an adjoining rotating member during operation.
According to a still further aspect, the present invention provides an apparatus for removal of hard rock and for splitting of mineral ore lumps in a sedimentary plane which include at least one pair of angled conveyors wherein an entrance gap is between each angled conveyor for passage of said mineral ore lumps is of greater size than an exit gap between each angled conveyor for departure of said mineral ore lumps and there is further provided in at least one of said conveyors a sagging or angled part of a chain or belt and each conveyor also includes a multiplicity of rotating rollers which contact said angled chain part to facilitate separation of impurity lumps from said mineral ore lumps. Each of the entrance gap and said exit gap may be adjustable in size.
A conveyor having said angled or sagging chain part may be located above an adjacent conveyor. Each of said angled conveyors may be provided with a plurality of spaced and transversely oriented cleats or grousers.
According to a still further aspect, the present invention provides an apparatus for separation of mineral ore lumps from impurity lumps including a conveyor and a striker or impact plate wherein mineral ore lumps entrained with impurity lumps are transferred to the conveyor and on leaving the conveyor are impacted against a striker or impact plate wherein the heavier impurity particles will have a departure angle that is less than a departure angle for the mineral ore particles facilitating separation of said impurity particles from said mineral ore particles. According to a still further aspect, the present invention provides an apparatus for separation of mineral ore lumps from impurity lumps having one or more rotating paddle wheels having paddles or projections which are oriented to each other at different angles as well as a striker or impact plate whereby impurity lumps entrained with mineral ore lumps are transferred to said one or more rotating paddle wheels and upon leaving said paddle wheel(s) impact on said striker or impact plate wherein impurity lumps will have a different departure angle to said mineral ore lumps thereby facilitating their separation.
The invention therefore provides a process for processing or refining a mineral ore which includes the following steps:
(i) passing lumps of said mineral ore through a space between at least one pair of rotating members to reduce the size of said lumps;
(ii) forwarding lumps having said reduced size through a pair of conveyors where said lumps are subject to impaction whereby lumps or particles substantially having a maximum dimension of between 25-150mm are collected;
(iii) separating ore lumps which have a lesser specific gravity from impurity lumps by impacting said lumps or particles produced from step (ii) on an impaction surface whereby said impurity lumps having a lesser departure angle than said ore lumps will be discarded; and
(iv) collecting the ore particles for further processing.
In step (i) there may be provided a hopper to feed run of mine mineral ore lumps, e.g. coal or metalliferous ore lumps, having a size of greater than 1200mm in the majority to the at least one pair of rotating members which preferably rotate in the same direction. The hopper normally is located above the at least one pair of rotating members and may have an exit opening and the mineral ore is pushed through the exit opening and between the pair of rotating members which are preferably rotating cylinders or truncated cones or which have a polygonal cross sectional shape. It is preferred that each of the rotating members are provided with impaction members which may be a series of projections or rods or tubes extending outwardly from a rotating member which are spaced apart from each other along the length of the rotating member and which mesh with each other or do not contact each other upon rotation of adjacent rotating members..
As described above this invention has wide application to mineral ores generally and is not limited to a coal ore. Accordingly any reference to a coal ore below or lumps of coal in the description of the invention contained below should equally be construed to be applicable to other ore materials and other lumps of ore. In particular it should also be construed to be applicable to metalliferous ores. In a variation of the above, the run of mine ore lumps may be discharged into a hopper and be subject to impaction by a pair of conveyors which may be arranged parallel to each other but which are more preferably angled towards each other. Each conveyor may have a belt or chain which suitably has a plurality of spaced impact members in the form of plates or grousers or cleats arranged transversely to the longitudinal axis of each conveyor. The use of the pair of conveyors as described above is suitable for processing particles having a maximum dimension lesser than 1200mm and more suitably about 500mm while the passage of coal ore lumps from the hopper directly to the rotating members is preferred for coal lumps having a maximum dimension greater than 1200mm such as about 2500-3500mm.
Hard rock removal and further splitting by plane separating unlike materials is facilitated by processing the rock stream longitudinally between the two flexible chain driven sets of grouser plates. The two sets or strings of plates are preferably oriented in the same direction and may be located one on top of the other and may travel in the same direction. The grouser and chain assembly can be similar to a conventional tractor having crawler tracks. The chain reaction points may be supported by track rollers.
Conventional crawler tracks have the track frames installed with a drive sprocket, return idlers and track rollers mounted in the vertical plane. The tractor weight and components of any imposed loads are transferred through the track rollers to the track chain supporting the reactions underneath them. It will be noted that when the track frame is hoisted vertically above the track chain, contact between grouser undersides and ground ceases. At that time the track sags below the track rollers. Conversely, when the entire track assembly is inverted, the track runs as an evenly distributed load across all of the track rollers.
Both track frames are preferably supported in a structure equipped with a resilient spring arrangement and adjustment means to align and space apart the track frames. Adjustment is made to the tracks in the vertical plane so that the grousers to ground contact surfaces are no longer parallel. Additionally, adjustment in the horizontal plane allows an entry space or gap created between two sets of grousers to decrease in height or taper along the length of track toward the exit area.
The adjustment in both vertical and horizontal planes produces the following large scale production results:
Lumps presented at the entry gap are caught in the tapering space as a track moves forward, wherein the track is supported by a plurality of rollers which maintains an essentially flat track surface
Gentle, constant track motion carries lumps along as they are presented between at least one track and another surface, for example, the another surface may be a track or a plurality of transverse bars etc;
Sag in the track cushions any load applied to the travelling lump;
Initially sagging track assembly weight per unit length applies progressively increasing load to the lump.
Usually the bond between remaining coal and other materials will shear under the load applied by the sagging track.
Large cohesive lumps of coal will separate into smaller lumps since the track load has been designed to exceed the impact work index for the coal being processed.
All fractured material is carried forward out of the crawler track machine as it forms a burden supported by at least one track by way of a resulting forward lump motion whereas the supporting surfaces may have the same velocities, different velocities or travel in opposite directions to each other at different magnitudes of velocity.
Any non-coal material, whether it is of igneous or sedimentary or other origin, capable of withstanding the sagging track load will begin to migrate toward the wider side of the tapering aperture between the track grousers. The horizontal component of the angularly applied load exceeds friction developed between the lump and track grouser plates. Similarly when one surface is stationary lumps carried forward by the at least one track impact on transverse bars so arranged by the aforesaid forward and transverse taper arrangements. The action of the lumps being carried forward by the at least one track impacts the lump against progressively lowering transverse tapered bars. The resulting reaction supplied by each bar surface results in a transverse reaction component as determined by resolved forces on a trigonometrical basis. The resulting reaction of the lumps occurs transversely to the opening aperture direction line and moves cohesively, any not easily sheared lumps away from the support of the forward moving conveyor,
(ix) Laterally ejected material from the opposed transfer chains is collected.
The following points are significant:
(a) The chain and grouser track assemblies are designed to gently restrain any lump that makes contact with any mating top and bottom grousers;
(b) Tough coal separation is a consequence of the squeeze applied;
(c) Oversized hard rock ejection is a consequence of the force resulting from the combined loading on the lump supported by the conveyor surfaces. The conveyor surfaces are orientated in such a way that their central axes are offset from each other and the resulting force on the hard rock causes the hard rock to be ejected.
(d) There is no crushing, mixing or grinding process involved. All lumps are sheared apart at a separating plane. Hard lumps are ejected laterally out of the space and/or pass along the space;
(e) The tapering aperture formed between the two track assemblies is a self cleaning accurate sizing process.
(f) No breaking or crushing operation/process impacts on undersize lumps; and
(g) Fines production is insignificant during the sizing process.
In regard to step (i) it will be appreciated that since sedimentary rock formations bulk into lumps of various shapes and sizes that such lumps will commonly have two adjacent flat surfaces displaced closely to each other. When these lumps fall into a space between rotating members such as rotating cylinders such cylinders may be driven and timed to each other to avoid the impaction projections described above from contacting each other and also allowing each following projection to contact any lumps falling from a previous cylinder. The rotational speed of each cylinder may be set to arrange the flat rock surfaces in a vertical aspect tangential to the rotating cylindrical external surfaces.
Suitably a plurality of rotating cylinders (e.g. 3-5) are used with the impaction projections constituted by at least one bar extending transversely through each cylinder wherein the at least one bar may be arranged in a line or in a staggered formation, staggered at between 10° to 90 Q and more preferably 10 ° to 25 Q and more suitably 15 Q with respect to each other. The use of rotating cylinders in step (i) is essentially a sizing process and it will be appreciated that (a) an aperture or gap formed between a pair of adjacent surfaces moving in opposite directions is a self cleaning accurate sizing process; (b) no crushing operation impacts on lumps and (c) fines production is insignificant during the sizing process.
It will also be appreciated that step (i) also concerns a process of lumps splitting along a plane separating un-like materials. Thus, the long flat squat lumps may be aligned parallel to the rotating cylinder centrelines or longitudinal axes with the flat surfaces tangential to the cylinder that they contact.
Entry between the rotating cylinders causes all lumps to progress forward at a speed, e.g., around 2 to 5 metres per second and preferably around 3 to 4 metres per second. All of the rotating cylinders rotate in the same direction and are driven and timed with respect to each other to avoid any clashing between adjacent rotating cylinders. In a first instance, the lump descends propelled forward by its own momentum into the gap between two rotating cylinders. Next, a driven impaction projection on an adjacent rotating cylinder performs work on the lump such that the lump will either become a smaller sized lump by disintegration of the lump or the lump will be driven into a short projectile orbit to have further work performed on the lump by a further adjacent rotating cylinder.
The process begins once again with the lump descending and another rotating cylinder with an impaction projection performing further work on the lump as described above. This process causes a shock wave to pass through the lump and facilitates breaking of a bond between a coal particle and an impurity particle present in the lump.
In the event that either the bond is not broken or no such bond exists then the lump still intact passes over an adjacent cylinder to repeat the process with the next cylinder. Depending on coal quality and/or other physical factors the next cylinder may have a different diameter, rotating bar arrangement and surface spacing to the previous cylinder.
The following points in relation to step (i) having regard to lump splitting is significant, i.e.:
(a) the drop height of the lumps between the rotating members is designed to dislodge coal at an interface between coal and non-coal or impurity surfaces;
(b) the coal to non coal interface has a weaker bond than does interfaces between various non-coal sedimentary materials or other materials;
(c) oversize hard rock passes over the cylinder assembly directly to the next step in the method of invention; and
(d) there is no crushing, mixing or grinding process involved.
In regard to step (ii) the abovementioned comments in relation to the use of a pair of impaction conveyors apply. It will also be appreciated that the pair of conveyors will preferably have a variable aperture or gap therebetween and this may be accomplished in one form by opposed sets of transfer chains or tracks which are subject to a different bias so that one transfer chain may be loosely supported and the other transfer chain may be more rigidly supported. For example, by having at least one chain or track more loosely supported around a series of rollers or supports allows that track to sag and therefore a variable gap or aperture is formed between a pair of conveyors. Similarly, a fixed series of stationary transverse bars may be fixed in a pre-determined profile to provide a rigid support in comparison with the flexible support described above. The fixed support may be more desirable in some cases where differing size and composition of the lumps exist.
Each transfer chain may have a set of grouser or impaction plates transversely attached thereto. It will be thus appreciated that with the differently biased transfer chains that the gap between the chains will open and close to accommodate the size of the lump passing therethrough. Therefore lumps are constrained to move forward into a space created by each chain.
Further in relation to step (ii) it will be appreciated that non-laterally discharged hard rocks pass directly between each transfer chain to be subject to step (iii). In relation to step (iii) it will be appreciated that this step is based on a realisation that differing amounts of energy contained in particles or lumps travelling in the same direction with the same constant velocity but having differing specific gravities can be separated by impaction on a striker plate or weighted surface when the particles or lumps are caused to become projectiles. Lumps or particles having the same geometry but different SG values when impacted side by side on a striker plate will deflect away from the original trajectory at different exit velocities which both differ from the original projectile velocity prior to impaction. When SG values between the coal and the sedimentary stone etc are quite similar it may be necessary to further vary the angle and/or the composition of the striker plate in order to separate the two different types of material.
Using a range of previously processed and/or similarly sized lumps of any SG value, lump stream paths are created by setting adjustable boundary limits. For example coal specific gravity varies up to 1 .4 whereas sedimentary stone, igneous rock and other like materials vary up from 1 .5 to as much as 4 or preferably 1 .7 to 2.8. Adjustable boundary limits can form separate chutes that accept light coal, heavy coal, mud stone, silt stone, clay stone, sand stone, basalt, siderite or dolerite or the like. The following points are significant:
(a) the impaction surfaces are designed to change the trajectory of lumps in a low energy exchange situation;
(b) sufficient stream paths are provided to direct impurity particles as well as coal particles;
(c) there is no crushing, mixing or grinding process involved as the separation path only varies projectile trajectory; and
(d) fines production is insignificant during the separation process. Yet another aspect of the invention relates to an apparatus for separation of mineral ore lumps from impurity lumps having one or more rotating paddle wheels having paddles or projections which are oriented to each other at different angles as well as a striker or impact plate whereby impurity lumps entrained with mineral ore lumps are transferred to said one or more rotating paddle wheels and upon leaving said paddle wheel(s) impact on said striker or impact plate wherein impurity lumps will have a different departure angle to said mineral ore lumps thereby facilitating their separation. The invention also includes within its scope sizing or mineral ore lump splitting apparatus having a plurality of rotating members wherein each rotating member has at least one impaction projection such as a bar or a tyne normally oriented to an external surface of each rotating member which pass through adjacent impaction tynes or projections on an adjoining rotating member during operation.
Another aspect of the invention relates to an apparatus for removal of hard rock and for splitting of mineral ore lumps in a sedimentary plane which include a pair of angled conveyors each having a plurality of spaced and transversely oriented cleats wherein an entrance gap is for the passage of said mineral ore lumps is of greater size than an exit gap for departure of said mineral ore lumps and there is further provided in one of said conveyors a sagging or angled part of a chain and each conveyor also includes a multiplicity of rotating rollers which contact said angled chain part to facilitate separation of impurity lumps from said mineral ore lumps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A mineral ore processing method and an apparatus for processing a mineral ore in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe several embodiments of the invention which relate to the processing of a mineral ore that is coal ore in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. In the drawings:
FIGS 1 A - 1 B illustrate step 1 of the invention in one aspect;
FIGS 2A - 2B illustrate step 1 of the invention on another aspect;
FIGS 3A - 3B are further perspective view of apparatus used in step 1 of the invention;
FIGS 4, 4A & 4B provide further elevation views of the pair of conveyors shown in FIG 2B;
FIGS 5A - 5B represent apparatus used in step 2 of the invention;
FIG 6 represents another alternative of step 2 of the invention; FIG 7 represents one aspect of step 3 of the invention;
FIG 8 represents another aspect of step 3 of the invention; and
FIG 9 provides an overall schematic view of the apparatus used in the process of the invention.
As described above this invention has wide application to mineral ores generally and is not limited to a coal ore. Accordingly any reference to a coal ore below or lumps of coal in the description of the invention contained below should equally be construed to be applicable to other ore materials and other lumps of ore. In particular it should also be construed to be applicable to metalliferous ores.
In FIGS 1 A and 1 B there is shown hopper 10, conveyor 1 1 , rocks or mineral aggregates or particles or lumps of ore 12, drive roller 13, idler roller 14, rotating cylinders 7, 8 and 9 all rotating in the same direction and each having impaction projections such as tynes or outwardly projecting rods or bars 17, 18, 19 and 20 which are arranged in pairs as shown in FIGS 3A to 3B. Each of the impaction projections forming a diameter of cylinders 7, 8 and 9 and also forming a diametric extension of cylinder 7 as shown in FIG 3B. Each pair of tynes 17, 18, 19 and 20 are arranged at 15 Q increments to each other as shown in FIG 1 B and 3A. In its most basic form the impaction projection may consist of a single bar or tyne extending outwardly from a side of the rotating cylinder. However, the impaction projection may consist of a single bar extending outwardly from either side of the rotating cylinder wherein the bar may form diametrically opposite extension or impaction projections on either side of the rotating cylinder. The process is initiated by lumps 12 being loaded into hopper 10 by any suitable loading apparatus such as an excavator, dump truck or end loader (not shown). As the lumps 12 reach the bottom open end 21 of hopper 10 they contact belt 22 of conveyor 1 1 and under the influence of drive roller 13 pass through the brow or opening 24 of hopper 10 to contact cylinder assembly 25 which comprises cylinders 7, 8 and 9 which are surrounded by a skirt 26 into which lumps 12 pass after being moved from open end 21 of hopper 10 by conveyor 1 1 . In order to perform the resize of the lump 12 at least one pair of rotating cylinders 7, 8, 9 is required. In Figures 1 B and 2B three rotating cylinders are shown however a person skilled in the art would realise that this process may be accomplished by a minimum of one pair of rotating cylinders rotating in the same direction. In a variation of the process as shown in FIGS 2A and 2B lumps 12 are passed into a hopper 1 1 A which has sloping side walls 27 and end wall 28 in contrast to hopper 1 1 which has vertical side walls 29 and vertical end wall 30. Hopper 1 1 A also has an open end 31 . In the arrangement shown in FIGS 2A and 2B lumps 12 passed between an open gap 32 between conveyors 33 and 34 each having drive rollers 35 and 36 and idler rollers 37 and 38. The gap 32 is adjustable and this may be accomplished by each idler roller 37 and 38 moving away from each other by virtue of having an axle (not shown) being pivotally mounted to a suitable support (not shown). Drive rollers 35 and 36 also have a similar pivotal mounting as idler rollers 37 and 38 with the exception that each of drive rollers are biased outwardly by an appropriate spring assembly (not shown). Thus drive rollers 35 and 36 form an adjustable gap 39.
The lump 12 therefore may be moved from the respective hoppers 10, 1 1 A by either of the above processes. The first process noted above using hopper 10 and conveyor 1 1 is an unregulated size flow. In this process any preferably sized lump will be placed in the hopper 10 and simply pass through the hopper 10 and onto the conveyor 1 1 and into the contact cylinder assembly 25 where the unregulated lumps 12 are sized.
In the second process in which hopper 1 1 A passes the lump 12 through to a pair of conveyors 33, 34 to produce a regulated size flow and regulated size lump 12. The lump 12 passes from the hopper 1 1 A into the pair of conveyors 33, 34 in which the size of the lump 12 is regulated to a certain size before entering the contact cylinder assembly 25 in which the regulated lump 12 is further sized. In both of the above processes a regulated or unregulated size flow produces a regulated lump size which allows for the effective operation of the at least one pair of rotating members or rotating cylinders 7, 8, 9.
To further determine which method to use to move the lump 12, two criteria are implemented. Firstly the size of the lump 12, and secondly the composition of the lump 12. Process management will determine a split and low parameter for a lump of mineral ore and to settle and determine a specific cut size.
If the size of lump 12 is less than 1200 mm then the lumps 12 are placed in the hopper 10 and reach the bottom open end 21 of hopper 10 they contact belt 22 of conveyor 1 1 and under the influence of drive roller 13 pass through the brow or opening 24 of hopper 10 to contact cylinder assembly 25.
If the size of the lump is greater than 1200 mm then the lumps 12 are placed in hopper 1 1 A and passed between an open gap 32 between conveyors 33 and 34 to contact cylinder assembly 25.
Finally the composition of the lump 12 may decide which of the above processes to use. For example a lump 12 may contain a large amount of coal ore and very little impurity particles however it may have a size greater than 1200 mm. Due to the amount of coal ore it may be the case that the bands which are formed at the interface of the impurities and coal will easily separate at the band and therefore it may be an advantage to use the hopper 10 and conveyor 1 1 to pass through the brow or opening 24 of hopper 10 to contact cylinder assembly 25. This also applies for lumps 12 which are less than 1200 mm in size and are formed from a large amount of impurity and smaller amounts of coal ore in which it may be beneficial to use the process of hopper 1 1 A and pass the lump 12 between an open gap 32 between conveyors 33 and 34 to contact cylinder assembly 25. It is important to stress that while each of conveyors 33 and 34 may have longitudinal axes that are offset to one another as shown in FIG 2B that such longitudinal axes may be parallel to each other if as desired.
It will also be appreciated that each of conveyors 33 and 34 may be vertically orientated as shown in FIG 4A or horizontally arranged as determined by relevant process parameters. FIG 4B is a detail of location "X" shown in FIG 4A. Each of conveyors 33 and 34 support an endless belt or chain 40 which are provided with cleats or grousers 41 transversely oriented to the longitudinal axis of each conveyor 33 and 34. It is preferred that each cleat or grouser 41 have a width that corresponds to the width of opening 31 of hopper 1 1 A. There also may be provided a single chain or belt 40 or multiple chains or belts 40 as may be required.
A grouser or cleat 41 is typically a protrusion on the surface of a continuous track segment or conveyor 33, 34. Grousers 41 may take the form of flat plates or bars, or may take on more complex shapes, including spikes and involute curves, depending on the type of material and the performance requirements of the conveyors 33, 34. Typically the grousers 41 are made of metal, such as forged steel. In FIG 4 there are provided any array of four rollers or cylinders 7A, 8A, 9A and 1 0A as opposed to an array of three cylinders 7, 8 and 9 shown in FIGS 1 B and 2B. Each of gaps 33A between each of rollers 7A and 8A, 8A and 9A, and 9A and 1 0A may be adjustable. Gaps 33A may be formed by each of rollers 7A, 8A, 9A and 10A being spring biased toward an upper position.
It will also be appreciated that the embodiment shown in FIGS 1 A and 1 B is used when the lumps are irregular and have very large sizes e.g. having a dimension greater than 1200mm. In other words, they will not pass through conveniently through gap 32 shown in FIG 2B. The embodiment of FIGS 2A and 2B may be used for smaller particles, having a dimension less than 1200mm.
The process described in FIGS 1 A, 1 B, 2A, 2B, 3A, 3B and 4A and 4B has the result of processing lumps 1 2 so that sedimentary lumps which have a multiplicity of bands or joints can be easily separated at these band or joint locations. Bands may occur at interfaces between mud stone, clay stone, silt stone and sand stone and coal and passing of such lumps 12 between conveyors 33 and 34 initially starts separation of coal particles from impurity particles along these bands. The velocity of conveyor 33 may be between 2.0 - 5.0 metres/second or preferably 3.0 to 4.0 metres/second and the velocity of conveyor 34 is preferably less than the speed of conveyor 34 by about 5-1 0%.
As above we note that conveyor 33 (vi) may have a different velocity than conveyor 34 (v 2 ). A number of different scenarios exist for the velocity of the conveyors which can be manipulated to easily separate the sedimentary lumps which have a multiplicity of bands or joints. The conveyors 33, 34 may travel at the same speed (v^ = v 2 ), or at different speeds (v^ > v 2 ) or (v^ < v 2 ). It is also possible that one of the conveyors may be stationary (v^ = 0) or (v 2 = 0) while the other conveyor travels at a certain speed. Finally it is also possible that one of the conveyors 33, 34 may travel in an opposite direction to the other conveyor 33, 34 (-v^ and +v 2 ) or (+v^ and -v 2 ).
The use of the angled gap 39 in FIG 2B facilitates control of flow of particles or lumps 1 2A so that they come into contact with cylinder assembly 25. Consequently, lumps 1 2A will only pass through gap 39 if they preferably have a size of 250mm or less as gap 39 is usually set at this limit. Therefore preferably the lumps 12A contacting cylinder assembly 25 will usually have a width of the order of 250mm or less. These particles will comprise lumps of stone and coal. The rotating cylinders 7, 8, 9 of the contacting cylinder assembly 25 are timed with respect to each other to avoid the impaction projections on adjacent cylinders from coming in contact with the impaction projections on the other adjacent cylinder. This is also the reason why the roatating cylinders are all rotated in the same direction.
The particles 12A after passing through cylinder 7, 8 and 9 and associated tynes 17, 18, 19 and 20 will be subject to shearing forces resulting from impact with tynes 17, 18, 19 and 20 thereby separating coal particles from stone lumps. The coal particles having a width of less than 250mm will then pass through gaps 33A as shown by particles 12B in FIG 2B and particles having a greater width of 250mm will then pass over cylinders 8 and 9 as shown by the arrows in FIG 1 B or shown by particles 12A in FIG 2B. The particles that are passed over cylinders 8 and 9 which have a size greater than the entrance gap 53A of conveyors 54 and 55 are excluded by a screening means (not shown).
Particles 12B will then be deposited on slat conveyor 51 shown in phantom in FIG 5A and in more detail in FIG 6. There is also provided a small roller or cylinder 52 having a tyne or projection 53 which will impact on particles 12A before they pass into entrance gap 53A of the at least one pair of conveyors 54 and 55 which have idler rollers 56 and 57 and drive rollers 58 and 59. Chain or belt 60A is also provided with cleats or grousers 41 A. As particles 12A pass through entrance gap 53A they will contact chain 60A which has a sagging or angled part 62 which contacts particles 12A. The chain 60A may be provided with sufficient weight so that contact with angled part 62 will separate coal particles 12C from any remaining stone or impurity particles wherein particles 12C will pass through exit gap 63 and such coal particles will preferably have a dimension of 25 - 50 mm. In another variation the contact chain 60A which forms a flexible support on conveyor 54 may be replaced by a fixed series of stationary transverse bars fixed in a predetermined profile to provide a rigid support to replace conveyor 54 and flexible contact chain 60A. Any stone particles present in gap 64 between conveyors 54 and 55 will impact on angled part 62 of the chain 60A so that angled part 62 will contact chain rollers 65 on each conveyor 54 and 55 as shown. This will have the effect on particles 12 or 12A travelling between offset conveyors 54 and 55 as experiencing a lateral resulting force as shown by arrows D, E and F in FIG 5B and thus some particles 12 and 12A fall away from conveyors 54 and 55 under the influence of gravity onto a conveyor 51 A shown in FIG 6. Particles 12 and 12A can be composite or discrete particles (i.e. impurity or mineral particles).
After passing between conveyors 54 and 55 particles 12 and 12A having a maximum dimension of 25-50mm may then pass through a further set of conveyors 70 and 71 as shown in FIG 6 wherein particles 12 and 12A are subject to the action of an impact cylinder 72 having a transversely oriented tyne 73 before passing into an entrance gap 74 between conveyors 70 and 71 which are also provided with chain 60A having an angled or sagging chain 62 and opposed sets of chain rollers 65 as shown in FIG 5A. The inclusion of a further set of conveyors 70 and 71 may be necessary in the case when exit gap 63 between conveyors 54 and 55 can only be adjusted to a minimum gap of 70- 80mm due to relevant site conditions. The passing of particles 12 and 12A through entrance gap 74, gap 75 and exit gap 76 between conveyors 70 and 71 will then ensure that particles 12 or 12A will have the desired dimension of 25-50mm. There is also shown conveyor belt conveyor 51 A which collects smaller particles. Coal particles 12D and impurity particles 12E and coal particles 12F of lesser size as well as impurity particles 12G of lesser size may be collected on high speed conveyor 80. It will also be appreciated that after passing through gap 63 the percentage of discrete particles is greater than particles passing between gap 53A. It will also be appreciated that particles exiting gap 76 will give a greater percentage of discrete particles than particles entering gap 74.
It will be appreciated from FIG 6 that smaller particles 12H which fall vertically from cylinder assembly 25, conveyors 54 and 55 and conveyors 70 and 71 will be collected by conveyor 51 transporting such particles to conveyor 80.
The next stage in the process of the invention is to pass the coal particles 12D and impurity particles 12E onto a high speed conveyor 80 having a speed of around 6-8m/sec wherein coal particles 12D entrained with stone particles 12E are impacted against striker or impact plate 81 wherein the heavier particles 12E will have a departure angle which is less than the departure angle of coal particles 12D thereby facilitating separation of coal particles 12D from stone particles 12E. Each of particles 12E and 12D may be collected on different conveyors (not shown) due to this difference in departure angle as shown in FIG 7.
In another variation for efficient separation of coal particles from stone or impurity particles 12D there is shown in FIG 8 particles or lumps 12D and 12E leaving exit gap 63 between conveyors 54 and 55 and being passed onto a rotating paddle wheel 84 having paddles 85 which are oriented to each other at different angles as shown. Each of paddles 85 may have an open or vented inner end to ensure that deposition of particles does not take place between each paddle 85 and the adjacent external surface 86 of each paddle wheel 84. Each of particles 12D and 12E may then impact on striker plate 88 so each will have a different departure angle as described in FIG 7 so that stone or impurity particles 12E may be collected by conveyor 90 and coal particles 12D impact on chute surface 92 as shown. There is also shown smaller particles 12F formed from coal and smaller stone particles 12G which are entrained with larger particles 12D and 12E. The stone particles 12E and 12G will collect on conveyor 90 and coal particles 12D and 12F will impact on chute surface 92.
Such particles 12D and 12F may be subject to the action of a further paddle wheel 84 and paddles 85 wherein particles 12D and 12E pass between gap 93 between return string 94 of conveyor 90 and hence, will impact on a further striker plate 95 so that stone particles 12G may be collected on conveyor 96 and coal particles 12D and 12F may be collected on conveyor 97.
Also in relation to this step it will be appreciated that this step is based on a realisation that differing amounts of energy contained in particles or lumps travelling in the same direction with the same constant velocity but having differing specific gravities (SG) can be separated by impaction on a striker plate or weighted surface when the particles or lumps 12D are caused to become projectiles. Specific gravity is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material.
In the case when SG values between the coal lumps 12D and the sedimentary stone 12E are quite similar it may be necessary to further vary the angle and/or the composition of the striker plate 81 in order to separate the two different types of material 12D, 12E. For example coal specific gravity varies up to 1 .4 whereas sedimentary stone, igneous rock and other like materials vary up from 1 .5 to as much as 4 or preferably 1 .7 to 2.8. Adjustable boundary limits can form separate chutes that accept light coal, heavy coal, mud stone, silt stone, clay stone, sand stone, basalt, siderite or dolerite or the like.
Finally, in FIG 9 there is provided coal processing plant 5 of the invention having hopper 10, cylinder assembly 25, conveyors 54 and 55 and separation plant 6 all being supported on a belt conveyor 51 A which is pivotally attached at 98A to a mounting trailer or frame 98 having ground supporting wheels 99. Coal particles separated from lumps 12 of ore are collected on a further belt conveyor 100 which is also supported on mounting frame or trailer 101 having ground supporting wheels 102. Both frame or trailer 101 may be articulated to frame or trailer 98 at 103. The coal particles after passage on conveyor 100 may be loaded onto transport vehicle 104 having storage space 105 and wheels 106.
Advantages of the process of the invention include the following:
(i) in regard to coal deposits being located in inaccessible regions, such deposits may be recovered using the process of the invention to reinstate operations without use of water.
all components used in the process of the invention can be transported by helicopter lift modules for shipment to the mining site and all product can be recovered using cable conveyors;
i. it also may be the case that the unwanted product may be left behind at the mining site to avoid any unnecessary transportation costs;
the process of the invention is based partly on the fact that sedimentary strata of any origin leaves or slips apparatus when gently restrained in a direction parallel to the relevant sedimentary planes and/or separating planes of different materials provides a very low energy process compared to conventional crushing processes. This is applicable for example to mining of coal deposits which are thin layers interposed between adjacent layers of silt stone, mud stone, sand stone or clay stone. Production efficiency is far greater using the process of the invention to this material compared to the conventional crushing process;
(iv) coal produced by the process of the invention is substantially free from ash producing materials and thus is environmentally friendly compared to conventional crushing processes which afford further significant advantages where the desirable product is used for combustible fuel purposes at high rates of use impurities or undesirable ash producing material included with the fuel contain both moisture and gritty abrasive components.
i. moisture in a combustion process releases carbon dioxide to the atmosphere exacerbating green house gas problems; and ii. abrasive components are entrained in boiler flue gas discharge which erodes expensive hot side boiler tubes and other sacrificial surfaces..
The process and apparatus described above has the potential to facilitate the processing of mineral ore deposits that are located in inaccessible regions. One advantageous feature of the process and apparatus is that it facilitates the recovery of certain deposits without the use of water.
Finally Applicant believes that this invention potentially has wide application across a range of mineral ores including metalliferous or metal ores as well as coal ores. In this specification the term "mineral ore" is to be interpreted broadly and without limiting the generality of the term it shall be interpreted to include all metal ores and also coal ores.
It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth.
In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".