AU2005297337B2

AU2005297337B2 - Crushing material

Info

Publication number: AU2005297337B2
Application number: AU2005297337A
Authority: AU
Inventors: Robin John Batterham; Richard Anthony Bearman; Raymond Walter Shaw
Original assignee: Technological Resources Pty Ltd
Current assignee: Technological Resources Pty Ltd
Priority date: 2004-10-22
Filing date: 2005-10-24
Publication date: 2011-08-04
Anticipated expiration: 2025-10-24
Also published as: AU2005297337A1

Abstract

A method and an apparatus for crushing material, particularly mined material, is disclosed. In one embodiment two or more pairs (3,7) of crushing rolls successively crush mined material. The pairs of crushing rolls are arranged and operated so that an upstream pair (3) of rolls produces a feed, preferably a pressurised feed, for a downstream pair (7) of rolls. In another embodiment, at least an upstream pair (3) of rolls is driven intermittently, for example by means of a stepping motor to provide stepped rotational movement of the rolls.

Description

CRUSHING MATERIAL The present invention relates to crushing material. The material may be any material that requires size reduction. 5 By way of example, the material may be mined material. By way of further example, the material may be biomass material. The following description of the invention focuses on crushing mined material. However, the present invention is io not confined to this material. The present invention relates particularly, although by no means exclusively, to crushing mined material and thereafter conveying the crushed material to another location for stockpiling and/or further processing the 15 material. The present invention relates more particularly, although by no means exclusively, to crushing mined material in situations in which there is limited working space where the material is mined and it is necessary to 20 convey the mined material to a remote location for stockpiling and/or further processing the material, such as processing to recover valuable material from the mined material. One such situation is in an underground mine, 25 particularly an underground mine for metalliferous material where it is necessary to convey mined material to the surface for further processing of the material. The present invention is based on the use of two or more pairs of crushing rolls that successively crush mined 2673381_1 (GHMatters) P53854.AU.1 - 2 material and are arranged and operated so that an upstream pair of rolls produces a feed, preferably a pressurised feed, for a downstream pair of rolls. Producing a feed, preferably a pressurised feed, for a downstream pair of 5 rolls facilitates efficient crushing of mined material. The present invention is also based on the realisation that driving at least an upstream pair of rolls intermittently, for example by means of a stepping motor to provide stepped rotational movement of io the rolls, provides considerable advantages. One advantage is that intermittent, such as stepped, rotation roll operation of at least the upstream pair of rolls allows gas to escape from the nip between rolls. Gas removal minimises the possibility of fluidising feed 15 material in the nip. Consequently, it is possible to improve throughput of feed material. Another advantage is that intermittent, such as stepped, rotation roll operation of at least the upstream pair of rolls allows moisture to drain from feed material 20 and thereby make it possible for the apparatus to handle semi-wet feed material without loss of particle size reduction. Water is an issue because it is incompressible and thereby reduces particle size reduction that could otherwise be achieved with a dry feed material. This 25 advantage is particularly relevant to biomass processing where it is hard to reduce moisture below say 20-50% by compression alone, even with porous rolls and piston and chamber compression. According to the present invention there is provided 30 an apparatus for crushing material that includes an upstream pair of crushing rolls adapted for intermittent 2673381_1 (GHMtters) P53884AU.1 - 3 rotation defining a nip therebetween for receiving feed material and crushing the feed material to a first particle size range and for forcing crushed material from the nip, a downstream pair of crushing rolls having a nip 5 therebetween for receiving crushed material from the upstream pair of rolls and crushing the feed material further to a second particle size range, and a transfer chute extending between the upstream and downstream pairs of rolls, whereby in use of the apparatus, crushed io material from the upstream pair of rolls forms a feed of material for the downstream pair of rolls as it moves through the transfer chute towards the downstream pair of rolls . Preferably the apparatus is adapted to form a 15 pressurised feed of crushed material moving through the transfer chute from the upstream pair of rolls to the downstream pair of rolls. The crushed material from the upstream pair of rolls may move as a non-pressurised gravity feed to the 20 downstream pair of rolls. In use, the resultant crushed material from the downstream pair of rolls may be conveyed to a remote location for stockpiling and/or further processing the material or directly fed into a processing plant or 25 otherwise handled as required in a given situation. The term "pair of crushing rolls" is understood herein to include arrangements in which the rolls in the pair of rolls that define a nip therebetween are backed up by back-up rolls. 2673381_1 (GHMatters) P53884AU.1 -4 Preferably the apparatus is adapted for intermittent rotation in the form of stepped rotation of the upstream pair of crushing rolls. The above-described apparatus may include any 5 suitable means for operating the upstream pair of rolls on a stepped rotation basis. One such suitable means is a stepping motor system. The present invention extends to other systems including mechanical systems. 10 The downstream pair of rolls may also be adapted for intermittent, such as stepped, rotation roll operation. The apparatus may include any suitable means for driving the downstream pair of rolls. By way of examples, is the means may be a stepping motor system or a mechanical system. In use, the resultant crushed material from the downstream pair of rolls may be conveyed to a remote location for stockpiling and/or further processing the 20 material or directly fed into a processing plant or otherwise handled as required in a given situation. Preferably the feed of material for the downstream pair of rolls is in the form of a moving packed bed of material in the transfer chute. 25 Preferably the apparatus is arranged so that, in use of the apparatus, the downstream pair of rolls is choke fed from the upstream pair of rolls. 2673381_1 (GHMatters) P53884.AU.1 - 5 The apparatus may include more than two pairs of rolls, with each pair of rolls successively crushing the material. Where there are only two pairs of rolls, preferably 5 the downstream pair of rolls is adapted to produce crushed material that has a particle size range that can be conveyed by gas or liquid in a pipeline. Where there are more than two pairs of rolls, preferably the most downstream pair of rolls is adapted to io produce crushed material that has a particle size range that can be conveyed by gas or liquid in a pipeline to another location for stockpiling and/or further processing the material. The rolls of the upstream and downstream pairs of is rolls may be any suitable size and form and be made from any suitable materials, including wear resistant materials. In terms of form, the rolls may have a smooth surface or may have raised sections, such as studs, to improve 20 wear resistance. In the case of an underground metalliferous mine, typically the top size of the feed material for the upstream pair of rolls is of the order of 90 mm for smooth rolls (but could be larger) and of the order of 60 mm for 25 studded rolls (but could be larger), the crushed material produced in the upstream pair of rolls is 5-10 mm, and the crushed material produced in the downstream or the most downstream pair of rolls is less than 2 mm. The apparatus may include a pre-crushing means, such 30 as jaw or gyratory crushers, for pre-crushing feed 2873351_1 (GHMaters) P53884 AU.1 -6 material to form the feed material for the upstream pair of crushing rolls. Preferably the apparatus further includes a means for exposing feed material to microwave energy for s physically and/or chemically altering the material prior to supplying the feed material to the downstream pair of rolls. Preferably the apparatus further includes a means for exposing crushed material flowing between upstream and 10 downstream pairs of rolls to microwave energy for physically and/or chemically altering the crushed material. Preferably the upstream pair of rolls produces crushed material that is in a form that is suitable for 15 microwave energy treatment of the material. For example, preferably the upstream rolls produce a uniform stream of crushed material that is well suited to microwave treatment. By way of further example, preferably the upstream rolls produce a defined geometry of crushed 20 material that is well suited to microwave treatment. The term "microwave energy" is understood herein to mean electromagnetic radiation that has frequencies in the range of 0.3-300 GHz. Preferably the microwave energy exposure means is 25 adapted to cause micro-cracking of crushed material that facilitates subsequent breakdown of crushed material in the downstream rolls. Preferably the microwave energy exposure means is adapted to expose the crushed material to pulsed high 30 energy microwave energy. 2673381_1 (GHMatters) P53884.AU.1 - 7 The term "high energy" is understood herein to mean values substantially above those within conventional household microwaves, ie substantially above 1 kW. Preferably the energy of the microwaves is at least 5 20 kW. More preferably the energy of the microwaves is at least 50 kW. The use of pulsed microwave energy minimises the power requirements of the method and maximises thermal 10 cycling of the ore particles. The time period of the pulses and the time period between pulses of microwave energy may be set as required depending on a number of factors. According to the present invention there is also is provided an apparatus for crushing material and thereafter transporting the crushed material to another location which includes the above-described crushing apparatus and a conveying means for conveying the crushed material (a) from the downstream pair of rolls to another location in 20 situations where there are only two pairs of crushing rolls or (b) from the most downstream pair of rolls to another location in situations where there are more than two pairs of rolls. Preferably the crushing apparatus includes a means 25 for feeding crushed material from the downstream or the most downstream pair of rolls into the conveying means. The feed means may include a means for accommodating pressure differences between the crushed 2673381.1 (GHMtters) P53884.AU.1 - 8 material produced by the crushing apparatus and the conveying means. The means for accommodating pressure differences 2673381_1 (GHMattefs) P53884AU.1 WO 2006/042378 PCT/AU2005/001645 -9 may include one or more than one lock hopper. Preferably the feed means is adapted to feed crushed material continuously into the conveying means. 5 Preferably the continuous feed means includes a screw feeder. Preferably the conveying means includes a 10 pipeline and a means for establishing a flow of gas or liquid through the pipeline for conveying crushed material in the pipeline. Preferably the conveying means includes a means 15 for separating the crushed material and the conveying gas or liquid at the other location. Preferably the conveying means includes a means for recycling separated gas or liquid. 20 According to the present invention there is also provided a method of crushing material that includes steps of supplying a feed material to a nip between an upstream pair of crushing rolls and crushing the feed material to a 25 first particle size range and producing a feed of crushed material and supplying the feed to a nip between a downstream pair of crushing rolls and crushing the feed material to a second particle size range. 30 Preferably the method includes producing a pressurised feed of crushed material in the upstream pair of crushing rolls. The method may include crushing the feed material 35 successively in more than two pairs of crushing rolls. Preferably the method further includes a step of WO 2006/042378 PCT/AU2005/001645 - 10 supplying the crushed material from the downstream pair of rolls into a pipeline and conveying the material through the pipeline to another location for stockpiling and/or further processing the material. 5 According to the present invention there is also provided a method of crushing material that includes the steps of supplying a feed material to a nip between a pair of crushing rolls rotating intermittently, such as in a 10 series of steps, and crushing the feed material to a first particle size range and producing a feed of crushed material. Preferably the method includes producing a 15 pressurised feed of crushed material. The method may also include supplying the feed from the above-described pair of rolls, ie an upstream pair of rolls, to a nip between a downstream pair of 20 crushing rolls and crushing the feed material to a second particle size range. The method may also include crushing the feed material successively in more than two pairs of crushing 25 rolls. Preferably the method further includes a step of supplying the crushed material from the (a) single roll pair in situations where there is one pair of rolls only, 30 (b) the downstream roll pair in situations where there are two roll pairs only or (c) the most downstream pair of rolls in situations where there are more than two roll pairs, into a pipeline and conveying the material through the pipeline to another location for stockpiling and/or 35 further processing the material. The present invention is described further with WO 2006/042378 PCT/AU2005/001645 - 11 reference to the accompanying drawing which is a schematic representation of one embodiment of an apparatus for crushing material and thereafter conveying transporting the crushed material to another location in accordance 5 with the present invention. With reference to the drawing, feed material that is mined, for example, in an underground metalliferous mine, and pre-crushed in a pre-crushing means (not shown), 10 such as jaw or gyratory crushers, to a top size of the order of 90 mm is supplied to a upstream pair of crushing rolls 3, each of which has a smooth surface, and is crushed to a first particle size range, typically 5-10 mm, by the rolls. 15 The upstream pair of crushing rolls 3 is connected to a stepping motor (not shown) that drives the rolls so that the rolls rotate intermittently, more particularly in a series of steps. The stepped rotation 20 of the rolls facilitates gas and moisture removal from the feed material and consequently improves roll performance and feed material throughput. The crushed material flows downwardly from the 25 upstream pair of rolls 3 in a transfer chute 5 to a downstream pair of crushing rolls 7 and is crushed further by these rolls, typically to a particle size of less than 2 mm. 30 Suitable seals (not shown) are provided between the transfer chute 5 and the upstream roll pair 3 on the one hand and between the transfer chute 5 and the downstream roll pair 7 on the other hand. 35 The arrangement and operation of the upstream and downstream roll pairs 3, 7 and the transfer chute 5 is such that the crushed material from the upstream roll pair WO 2006/042378 PCT/AU2005/001645 - 12 3 forms a pressurised feed of material for the downstream roll pair 7. More particularly, the crushed material from the upstream roll pair 3 forms a moving packed bed of crushed material. The pressurised feed for the downstream 5 roll pair 7 facilitates efficient crushing of the material in the downstream roll pair 7. The crushed material from the downstream roll pair 7 flows downwardly in a transfer chute 13 into a 10 continuous feeder in the form of a screw feeder 9. The arrangement and operation of the downstream roll pair 7 and the transfer chute 13 is such that the crushed material from the downstream roll pair 7 forms a 15 pressurised feed for the screw feeder 9. Suitable seals (not shown) are provided between the transfer chute 13 and the downstream roll pair 7 on the one hand and between the transfer chute 13 and the 20 screw feeder 9 on the other hand to accommodate pressure differences between the different sections of the apparatus and, in particular, to prevent flow of material from the pipeline into the screw feeder 9 and from the screw feeder 9 upstream of the screw feeder. 25 The screw feeder 9 transports the crushed material to a pipeline 11. A suitable gas or liquid, typically water, conveys the crushed material in the pipeline 11 to a remote location for stockpiling and/or 30 further processing. The further processing may include separating the crushed material form the conveying gas or liquid. The rolls of the upstream and downstream roll 35 pairs 3, 7 may be any suitable rolls for crushing the mined material.

WO 2006/042378 PCT/AU2005/001645 - 13 The above-described apparatus also includes a microwave generator 15 that emits pulsed high energy microwave energy through the crushed material flowing through the transfer chute 5 and causes micro-cracking of 5 the material that facilitates subsequent breakdown of the material in the downstream roll pair 7. The upstream roll pair 3 produces crushed material that is in a form that is suitable for microwave 10 energy treatment of the material. Specifically, the upstream roll pair 3 produces a uniform stream of crushed material that is well suited to microwave treatment. In addition, the upstream roll pair 3 produces a defined geometry of crushed material that is well suited to 15 microwave treatment. The above-described apparatus is compact and can be positioned in working environments, such as underground mines, which have space constraints, and can efficiently 20 crush mined material to a size that can be conveyed in a pipeline to another location. Many modifications may be made to the embodiment of the present invention described above without departing 25 from the spirit and scope of the invention. For example, whilst the embodiment includes two roll pairs, with the upstream roll pair 3 operating on a stepped basis, the present invention is not so limited and 30 extends to single roll pair operation and to more than two roll pair operation operating on a stepped, or any other suitable intermittent rotation, basis. In addition, whilst the embodiment is described 35 in the context of the use of a stepping motor, the present invention is not so limited and extends to any means for WO 2006/042378 PCT/AU2005/001645 - 14 causing intermittent operation of the upstream roll pair 3. In addition, whilst the embodiment is described 5 in the context of operating the upstream roll pair 3 on a stepped basis, the present invention is not so limited and extends to operating the upstream roll pair on a continuous basis. 10 In addition, whilst the embodiment is described in the context of crushing mined material, the present invention is not so limited and extends to any suitable application in which it is necessary to crush material. As is indicated specifically above, by way of example, one 15 such other material is biomass material. In addition, whilst the embodiment is described in the context of mined material obtained by underground mining of metalliferous material, the present invention is 20 not so limited and extends to any suitable application in which it is necessary to crush mined material. In addition, whilst the embodiment includes conveying the crushed material from the downstream roll 25 pair 7 in the pipeline 11 to a remote location for stockpiling and/or further processing, the present invention is not so limited and extends to any suitable downstream processing of the crushed material. For example, the crushed material may be fed directly into a 30 processing plant. In addition, whilst the embodiment includes forming a pressurised feed of material in the upstream roll pair 3, the present invention is not so limited and 35 extends to forming a non-pressurised feed in the transfer chute 5. For example, the feed of crushed material from WO 2006/042378 PCT/AU2005/001645 - 15 the upstream roll pair 3 may move by gravity feed in the chute 5 to the downstream roll pair 7. In addition, whilst the embodiment includes 5 transporting crushed material in a pipeline 11 from the screw feeder 9 to the downstream stockpile or for further processing, the present invention is not so limited and extends to any suitable means for transporting crushed material from one location to another location.

Claims

1. An apparatus for crushing material that includes an upstream pair of crushing rolls adapted for intermittent rotation defining a nip therebetween for receiving feed s material and crushing the feed material to a first particle size range and for forcing crushed material from the nip, a downstream pair of crushing rolls having a nip therebetween for receiving crushed material from the upstream pair of rolls and crushing the feed material 10 further to a second particle size range, and a transfer chute extending between the upstream and downstream pairs of rolls and confining crushed material from the upstream pair of rolls to move to the downstream pair of rolls, whereby in use of the apparatus, crushed material from the 15 upstream pair of rolls forms a feed of material for the downstream pair of rolls as it moves through the transfer chute to the downstream pair of rolls.

2. The apparatus defined in claim 1 adapted to form a pressurised feed of material moving through the transfer 20 chute from the upstream pair of rolls to the downstream pair of rolls.

3. The apparatus defined in claim 1 or claim 2 wherein the upstream pair of rolls is adapted for stepped rotation roll operation. 25

4. The apparatus defined in claim 3 includes a stepping motor system for operating the pair of crushing rolls on a stepped rotation basis.

5. The apparatus defined in any one of the preceding claims wherein the downstream pair of rolls is adapted for 30 intermittent, such as stepped, rotation roll operation. 2573381_1 (GHManers) P53884AU.1 - 17

6. The apparatus defined in any one of the preceding claims wherein the pressurised feed of material for the downstream pair of rolls is in the form of a moving packed bed of material in the transfer chute. 5

7. The apparatus defined in any one of the preceding claims wherein, in use of the apparatus, the downstream pair of rolls is choke fed from the upstream pair of rolls.

8. The apparatus defined in any one of the preceding 10 claims includes a means for exposing feed material to microwave energy for physically and/or chemically altering the material prior to supplying the feed material to the upstream pair of rolls

9. The apparatus defined in claim 8 wherein the upstream is pair of rolls is adapted to produce a uniform stream of crushed material that is suited to microwave treatment.

10. The apparatus defined in claim 8 or claim 9 wherein the means for exposing feed material to microwave energy is adapted to emit pulsed high energy microwave energy 20 through crushed material flowing through the transfer chute to facilitate subsequent breakdown of the material in the downstream pair of rolls.

11. The apparatus defined in any one of the preceding claims includes a means for exposing crushed material 25 flowing between upstream and downstream pairs of rolls to microwave energy for physically and/or chemically altering the crushed material.

12. An apparatus for crushing material and thereafter transporting the crushed material to another location 30 which includes the crushing apparatus defined in any one 2073381_1 (GHMatters) PS3884.AU.1 - 18 of the preceding claims and a conveying means for conveying the crushed material (a) from the downstream pair of rolls to another location in situations where there are only two pairs of crushing rolls or (b) from the 5 most downstream pair of rolls to another location in situations where there are more than two pairs of rolls.

13. A method of crushing material that includes steps of supplying a feed material to a nip between an upstream pair of crushing rolls and crushing the feed material to a 10 first particle size range and producing a feed of crushed material and supplying the feed to a nip between a downstream pair of crushing rolls and crushing the feed material to a second particle size range.

14. The method defined in claim 13 includes producing a 15 pressurised feed of crushed material in the upstream pair of crushing rolls.

15. The method defined in claim 13 or claim 14 includes rotating the upstream pair of rolls intermittently.

16. The method defined in any one of claims 13 to 15 20 includes crushing the feed material successively in more than two pairs of crushing rolls.

17. The method defined in any one of claims 13 to 16 includes a step of supplying the crushed material from (a) the downstream roll pair in situations where there are two 25 roll pairs only or (b) the most downstream pair of rolls in situations where there are more than two roll pairs, into a pipeline and conveying the material through the pipeline to another location for stockpiling and/or further processing the material. 2073381_1 (GHMatter) P53884.AU.1 - 19

18. The method defined in any one of claims 13 to 17 includes exposing feed material to microwave energy and physically and/or chemically altering the material prior to supplying the feed material to the upstream pair of 5 rolls.

19. The method defined in any one of claims 13 to 18 includes exposing crushed material flowing between upstream and downstream pairs of rolls to microwave energy and physically and/or chemically altering the crushed 10 material.

20. The method defined in claim 19 includes producing a uniform stream of crushed material that is suited to microwave treatment flowing between upstream and downstream pairs of rolls. 1s

21. The method defined in claim 19 or claim 20 includes exposing feed material flowing between upstream and downstream pairs of rolls to pulsed high energy microwave energy to facilitate subsequent breakdown of the material in the downstream pair of rolls. 20 2673381_1 (GHMatters) P53884.AU.1